kfence: Avoid stalling work queue task without allocations

PATCH In review Marco Elver 8 participants 63 messages Nov 10, 2020 – Nov 25, 2020 Page 1 of 2

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Marco Elver

author maintainer

2020-11-10 13:53 UTC #0 lore raw

PATCH 1/1 kfence: Avoid stalling work queue task without allocations

To toggle the allocation gates, we set up a delayed work that calls toggle_allocation_gate(). Here we use wait_event() to await an allocation and subsequently disable the static branch again. However, if the kernel has stopped doing allocations entirely, we'd wait indefinitely, and stall the worker task. This may also result in the appropriate warnings if CONFIG_DETECT_HUNG_TASK=y.

Therefore, introduce a 1 second timeout and use wait_event_timeout(). If the timeout is reached, the static branch is disabled and a new delayed work is scheduled to try setting up an allocation at a later time.

Note that, this scenario is very unlikely during normal workloads once the kernel has booted and user space tasks are running. It can, however, happen during early boot after KFENCE has been enabled, when e.g. running tests that do not result in any allocations.

Link https://lkml.kernel.org/r/CADYN=9J0DQhizAGB0-jz4HOBBh+05kMBXb4c0cXMS7Qi5NAJiw@mail.gmail.com open here

Reported-by Anders Roxell <[email protected]>

Signed-off-by Marco Elver <[email protected]>

---
 mm/kfence/core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

mm/kfence/core.c +5 -1

index 9358f42a9a9e..933b197b8634 100644
@@ -592,7 +592,11 @@ static void toggle_allocation_gate(struct work_struct *work)
 	/* Enable static key, and await allocation to happen. */
 	atomic_set(&allocation_gate, 0);
 	static_branch_enable(&kfence_allocation_key);
-	wait_event(allocation_wait, atomic_read(&allocation_gate) != 0);
+	/*
+	 * Await an allocation. Timeout after 1 second, in case the kernel stops
+	 * doing allocations, to avoid stalling this worker task for too long.
+	 */
+	wait_event_timeout(allocation_wait, atomic_read(&allocation_gate) != 0, HZ);
 
 	/* Disable static key and reset timer. */
 	static_branch_disable(&kfence_allocation_key);

Signature · 1 line

2.29.2.222.g5d2a92d10f8-goog

Dmitry Vyukov

reviewer

2020-11-10 14:25 UTC #1 lore raw

Quoted 29 lines · Marco Elver

To toggle the allocation gates, we set up a delayed work that calls toggle_allocation_gate(). Here we use wait_event() to await an allocation and subsequently disable the static branch again. However, if the kernel has stopped doing allocations entirely, we'd wait indefinitely, and stall the worker task. This may also result in the appropriate warnings if CONFIG_DETECT_HUNG_TASK=y.
Therefore, introduce a 1 second timeout and use wait_event_timeout(). If the timeout is reached, the static branch is disabled and a new delayed work is scheduled to try setting up an allocation at a later time.
Note that, this scenario is very unlikely during normal workloads once the kernel has booted and user space tasks are running. It can, however, happen during early boot after KFENCE has been enabled, when e.g. running tests that do not result in any allocations.
Link https://lkml.kernel.org/r/CADYN=9J0DQhizAGB0-jz4HOBBh+05kMBXb4c0cXMS7Qi5NAJiw@mail.gmail.com open here
Reported-by Anders Roxell <[email protected]>
Signed-off-by Marco Elver <[email protected]>
---
 mm/kfence/core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
mm/kfence/core.c +0 -0
index 9358f42a9a9e..933b197b8634 100644

mm/kfence/core.c static void toggle_allocation_gate(struct work_struct *work) · line 599

Quoted 9 lines

mm/kfence/core.c +5 -1

@@ -592,7 +592,11 @@ static void toggle_allocation_gate(struct work_struct *work)
        /* Enable static key, and await allocation to happen. */
        atomic_set(&allocation_gate, 0);
        static_branch_enable(&kfence_allocation_key);
-       wait_event(allocation_wait, atomic_read(&allocation_gate) != 0);
+       /*
+        * Await an allocation. Timeout after 1 second, in case the kernel stops
+        * doing allocations, to avoid stalling this worker task for too long.
+        */
+       wait_event_timeout(allocation_wait, atomic_read(&allocation_gate) != 0, HZ);

I wonder what happens if we get an allocation right when the timeout fires. Consider, another task already went to the slow path and is about to wake this task. This task wakes on timeout and subsequently enables static branch again. Now we can have 2 tasks on the slow path that both will wake this task. How will it be handled? Can it lead to some warnings or something?

Quoted 4 lines

mm/kfence/core.c +0 -1

        /* Disable static key and reset timer. */
        static_branch_disable(&kfence_allocation_key);
--

2.29.2.222.g5d2a92d10f8-goog

Marco Elver

author maintainer

2020-11-10 14:54 UTC #2 lore raw

Quoted 37 lines · Dmitry Vyukov

Quoted 36 lines · Marco Elver
To toggle the allocation gates, we set up a delayed work that calls toggle_allocation_gate(). Here we use wait_event() to await an allocation and subsequently disable the static branch again. However, if the kernel has stopped doing allocations entirely, we'd wait indefinitely, and stall the worker task. This may also result in the appropriate warnings if CONFIG_DETECT_HUNG_TASK=y.
Therefore, introduce a 1 second timeout and use wait_event_timeout(). If the timeout is reached, the static branch is disabled and a new delayed work is scheduled to try setting up an allocation at a later time.
Note that, this scenario is very unlikely during normal workloads once the kernel has booted and user space tasks are running. It can, however, happen during early boot after KFENCE has been enabled, when e.g. running tests that do not result in any allocations.
Link https://lkml.kernel.org/r/CADYN=9J0DQhizAGB0-jz4HOBBh+05kMBXb4c0cXMS7Qi5NAJiw@mail.gmail.com open here
Reported-by Anders Roxell <[email protected]>
Signed-off-by Marco Elver <[email protected]>
---
 mm/kfence/core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
mm/kfence/core.c +4 -1
index 9358f42a9a9e..933b197b8634 100644
@@ -592,7 +592,11 @@ static void toggle_allocation_gate(struct work_struct *work)
        /* Enable static key, and await allocation to happen. */
        atomic_set(&allocation_gate, 0);
        static_branch_enable(&kfence_allocation_key);
-       wait_event(allocation_wait, atomic_read(&allocation_gate) != 0);
+       /*
+        * Await an allocation. Timeout after 1 second, in case the kernel stops
+        * doing allocations, to avoid stalling this worker task for too long.
+        */

Quoted 8 lines

mm/kfence/core.c static void toggle_allocation_gate(struct work_struct *work) · line 599
Quoted 1 line
mm/kfence/core.c +1 -0
+       wait_event_timeout(allocation_wait, atomic_read(&allocation_gate) != 0, HZ);
I wonder what happens if we get an allocation right when the timeout fires. Consider, another task already went to the slow path and is about to wake this task. This task wakes on timeout and subsequently enables static branch again. Now we can have 2 tasks on the slow path that both will wake this task. How will it be handled? Can it lead to some warnings or something?

wake_up() does not require tasks to be in the wait queue, nor is there any requirement that it's exclusive (it takes the appropriate locks unlike wake_up_locked()). One of the wake_up() calls will wake the task, and the other is a noop. So this will work just fine.

Thanks,
-- Marco

Anders Roxell

2020-11-10 23:23 UTC #3 lore raw

In reply to Marco Elver

Quoted 42 lines · Marco Elver

To toggle the allocation gates, we set up a delayed work that calls toggle_allocation_gate(). Here we use wait_event() to await an allocation and subsequently disable the static branch again. However, if the kernel has stopped doing allocations entirely, we'd wait indefinitely, and stall the worker task. This may also result in the appropriate warnings if CONFIG_DETECT_HUNG_TASK=y.
Therefore, introduce a 1 second timeout and use wait_event_timeout(). If the timeout is reached, the static branch is disabled and a new delayed work is scheduled to try setting up an allocation at a later time.
Note that, this scenario is very unlikely during normal workloads once the kernel has booted and user space tasks are running. It can, however, happen during early boot after KFENCE has been enabled, when e.g. running tests that do not result in any allocations.
Link https://lkml.kernel.org/r/CADYN=9J0DQhizAGB0-jz4HOBBh+05kMBXb4c0cXMS7Qi5NAJiw@mail.gmail.com open here
Reported-by Anders Roxell <[email protected]>
Signed-off-by Marco Elver <[email protected]>
---
 mm/kfence/core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
mm/kfence/core.c +5 -2
index 9358f42a9a9e..933b197b8634 100644
@@ -592,7 +592,11 @@ static void toggle_allocation_gate(struct work_struct *work)
        /* Enable static key, and await allocation to happen. */
        atomic_set(&allocation_gate, 0);
        static_branch_enable(&kfence_allocation_key);
-       wait_event(allocation_wait, atomic_read(&allocation_gate) != 0);
+       /*
+        * Await an allocation. Timeout after 1 second, in case the kernel stops
+        * doing allocations, to avoid stalling this worker task for too long.
+        */
+       wait_event_timeout(allocation_wait, atomic_read(&allocation_gate) != 0, HZ);
 
        /* Disable static key and reset timer. */
        static_branch_disable(&kfence_allocation_key);
--

Quoted 2 lines

2.29.2.222.g5d2a92d10f8-goog

I gave them a spin on next-20201105 [1] and on next-20201110 [2].

I eventually got to a prompt on next-20201105. However, I got to this kernel panic on the next-20201110:

[...]

[ 1514.089966][    T1] Testing event system initcall: OK
[ 1514.806232][    T1] Running tests on all trace events:
[ 1514.857835][    T1] Testing all events:
[ 1525.503262][    C0] hrtimer: interrupt took 10902600 ns
[ 1623.861452][    C0] BUG: workqueue lockup - pool cpus=0 node=0
flags=0x0 nice=0 stuck for 65s!
[...]
[ 7823.104349][   T28]       Tainted: G        W
5.10.0-rc3-next-20201110-00008-g8dc06700529d #3
[ 7833.206491][   T28] "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 7840.750700][   T28] task:kworker/0:1     state:D stack:26640 pid:
1872 ppid:     2 flags:0x00000428
[ 7875.642531][   T28] Workqueue: events toggle_allocation_gate
[ 7889.178334][   T28] Call trace:
[ 7897.066649][   T28]  __switch_to+0x1cc/0x1e0
[ 7905.326856][   T28]  0xffff00000f7077b0
[ 7928.354644][   T28] INFO: lockdep is turned off.
[ 7934.022572][   T28] Kernel panic - not syncing: hung_task: blocked tasks
[ 7934.032039][   T28] CPU: 0 PID: 28 Comm: khungtaskd Tainted: G
  W         5.10.0-rc3-next-20201110-00008-g8dc06700529d #3
[ 7934.045586][   T28] Hardware name: linux,dummy-virt (DT)
[ 7934.053677][   T28] Call trace:
[ 7934.060276][   T28]  dump_backtrace+0x0/0x420
[ 7934.067635][   T28]  show_stack+0x38/0xa0
[ 7934.091277][   T28]  dump_stack+0x1d4/0x278
[ 7934.098878][   T28]  panic+0x304/0x5d8
[ 7934.114923][   T28]  check_hung_uninterruptible_tasks+0x5e4/0x640
[ 7934.123823][   T28]  watchdog+0x138/0x160
[ 7934.131561][   T28]  kthread+0x23c/0x260
[ 7934.138590][   T28]  ret_from_fork+0x10/0x18
[ 7934.146631][   T28] Kernel Offset: disabled
[ 7934.153749][   T28] CPU features: 0x0240002,20002004
[ 7934.161476][   T28] Memory Limit: none
[ 7934.171272][   T28] ---[ end Kernel panic - not syncing: hung_task:

blocked tasks ]---

Cheers,
Anders
[1] https://people.linaro.org/~anders.roxell/output-next-20201105-test.log
[2] https://people.linaro.org/~anders.roxell/output-next-20201110-test.log

Marco Elver

author maintainer

2020-11-11 08:29 UTC #4 lore raw

On Wed, 11 Nov 2020 at 00:23, Anders Roxell <[email protected]> wrote:
[...]

Quoted 42 lines

I gave them a spin on next-20201105 [1] and on next-20201110 [2].

I eventually got to a prompt on next-20201105. However, I got to this kernel panic on the next-20201110:

[...]

[ 1514.089966][    T1] Testing event system initcall: OK
[ 1514.806232][    T1] Running tests on all trace events:
[ 1514.857835][    T1] Testing all events:
[ 1525.503262][    C0] hrtimer: interrupt took 10902600 ns
[ 1623.861452][    C0] BUG: workqueue lockup - pool cpus=0 node=0
flags=0x0 nice=0 stuck for 65s!
[...]
[ 7823.104349][   T28]       Tainted: G        W
5.10.0-rc3-next-20201110-00008-g8dc06700529d #3
[ 7833.206491][   T28] "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 7840.750700][   T28] task:kworker/0:1     state:D stack:26640 pid:
1872 ppid:     2 flags:0x00000428
[ 7875.642531][   T28] Workqueue: events toggle_allocation_gate
[ 7889.178334][   T28] Call trace:
[ 7897.066649][   T28]  __switch_to+0x1cc/0x1e0
[ 7905.326856][   T28]  0xffff00000f7077b0
[ 7928.354644][   T28] INFO: lockdep is turned off.
[ 7934.022572][   T28] Kernel panic - not syncing: hung_task: blocked tasks
[ 7934.032039][   T28] CPU: 0 PID: 28 Comm: khungtaskd Tainted: G
  W         5.10.0-rc3-next-20201110-00008-g8dc06700529d #3
[ 7934.045586][   T28] Hardware name: linux,dummy-virt (DT)
[ 7934.053677][   T28] Call trace:
[ 7934.060276][   T28]  dump_backtrace+0x0/0x420
[ 7934.067635][   T28]  show_stack+0x38/0xa0
[ 7934.091277][   T28]  dump_stack+0x1d4/0x278
[ 7934.098878][   T28]  panic+0x304/0x5d8
[ 7934.114923][   T28]  check_hung_uninterruptible_tasks+0x5e4/0x640
[ 7934.123823][   T28]  watchdog+0x138/0x160
[ 7934.131561][   T28]  kthread+0x23c/0x260
[ 7934.138590][   T28]  ret_from_fork+0x10/0x18
[ 7934.146631][   T28] Kernel Offset: disabled
[ 7934.153749][   T28] CPU features: 0x0240002,20002004
[ 7934.161476][   T28] Memory Limit: none
[ 7934.171272][   T28] ---[ end Kernel panic - not syncing: hung_task:

Quoted 6 lines

blocked tasks ]---
Cheers,
Anders
[1] https://people.linaro.org/~anders.roxell/output-next-20201105-test.log
[2] https://people.linaro.org/~anders.roxell/output-next-20201110-test.log

Thanks for testing. The fact that it passes on next-20201105 but not on 20201110 is strange. If you boot with KFENCE disabled (boot param kfence.sample_interval=0), does it boot?

In your log [2] I see a number of "BUG: workqueue lockup ..." but that doesn't make sense, at least I don't think the KFENCE work item is causing this. It'd be interesting to bisect what changed between 20201105 and 20201110, but I have a suspicion that might take too long. Short of that, let me see if there are any changes between the 2 that look like it might be causing this.

Thanks,
-- Marco

Marco Elver

author maintainer

2020-11-11 13:38 UTC #5 lore raw

[+Cc folks who can maybe help figure out what's going on, since I get
warnings even without KFENCE on next-20201110.]

Quoted 45 lines · Marco Elver

On Wed, 11 Nov 2020 at 00:23, Anders Roxell <[email protected]> wrote:
[...]

Quoted 43 lines

I gave them a spin on next-20201105 [1] and on next-20201110 [2].

I eventually got to a prompt on next-20201105. However, I got to this kernel panic on the next-20201110:

[...]

[ 1514.089966][    T1] Testing event system initcall: OK
[ 1514.806232][    T1] Running tests on all trace events:
[ 1514.857835][    T1] Testing all events:
[ 1525.503262][    C0] hrtimer: interrupt took 10902600 ns
[ 1623.861452][    C0] BUG: workqueue lockup - pool cpus=0 node=0
flags=0x0 nice=0 stuck for 65s!
[...]
[ 7823.104349][   T28]       Tainted: G        W
5.10.0-rc3-next-20201110-00008-g8dc06700529d #3
[ 7833.206491][   T28] "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 7840.750700][   T28] task:kworker/0:1     state:D stack:26640 pid:
1872 ppid:     2 flags:0x00000428
[ 7875.642531][   T28] Workqueue: events toggle_allocation_gate
[ 7889.178334][   T28] Call trace:
[ 7897.066649][   T28]  __switch_to+0x1cc/0x1e0
[ 7905.326856][   T28]  0xffff00000f7077b0
[ 7928.354644][   T28] INFO: lockdep is turned off.
[ 7934.022572][   T28] Kernel panic - not syncing: hung_task: blocked tasks
[ 7934.032039][   T28] CPU: 0 PID: 28 Comm: khungtaskd Tainted: G
  W         5.10.0-rc3-next-20201110-00008-g8dc06700529d #3
[ 7934.045586][   T28] Hardware name: linux,dummy-virt (DT)
[ 7934.053677][   T28] Call trace:
[ 7934.060276][   T28]  dump_backtrace+0x0/0x420
[ 7934.067635][   T28]  show_stack+0x38/0xa0
[ 7934.091277][   T28]  dump_stack+0x1d4/0x278
[ 7934.098878][   T28]  panic+0x304/0x5d8
[ 7934.114923][   T28]  check_hung_uninterruptible_tasks+0x5e4/0x640
[ 7934.123823][   T28]  watchdog+0x138/0x160
[ 7934.131561][   T28]  kthread+0x23c/0x260
[ 7934.138590][   T28]  ret_from_fork+0x10/0x18
[ 7934.146631][   T28] Kernel Offset: disabled
[ 7934.153749][   T28] CPU features: 0x0240002,20002004
[ 7934.161476][   T28] Memory Limit: none
[ 7934.171272][   T28] ---[ end Kernel panic - not syncing: hung_task:

blocked tasks ]---

Quoted 8 lines

Quoted 4 lines
Cheers,
Anders
[1] https://people.linaro.org/~anders.roxell/output-next-20201105-test.log
[2] https://people.linaro.org/~anders.roxell/output-next-20201110-test.log
Thanks for testing. The fact that it passes on next-20201105 but not on 20201110 is strange. If you boot with KFENCE disabled (boot param kfence.sample_interval=0), does it boot?

[...]

Right, so I think this is no longer KFENCE's fault. This looks like something scheduler/RCU/ftrace related?! I notice that there have been scheduler changes between next-20201105 and next-20201110.

I get this with KFENCE disabled:

| Running tests on all trace events:
| Testing all events: 
| BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 32s!
| Showing busy workqueues and worker pools:
| workqueue events: flags=0x0
|   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
|     pending: vmstat_shepherd
| workqueue events_power_efficient: flags=0x82
|   pwq 2: cpus=0 flags=0x5 nice=0 active=2/256 refcnt=4
|     in-flight: 107:neigh_periodic_work
|     pending: do_cache_clean
| pool 2: cpus=0 flags=0x5 nice=0 hung=3s workers=2 manager: 7
| rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
| 	(detected by 0, t=6502 jiffies, g=2885, q=4)
| rcu: All QSes seen, last rcu_preempt kthread activity 5174 (4295523265-4295518091), jiffies_till_next_fqs=1, root ->qsmask 0x0
| rcu: rcu_preempt kthread starved for 5174 jiffies! g2885 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
| rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
| rcu: RCU grace-period kthread stack dump:
| task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
| Call trace:
|  __switch_to+0x100/0x1e0
|  __schedule+0x2d0/0x890
|  preempt_schedule_notrace+0x70/0x1c0
|  ftrace_ops_no_ops+0x174/0x250
|  ftrace_graph_call+0x0/0xc
|  preempt_count_add+0x1c/0x180
|  schedule+0x44/0x108
|  schedule_timeout+0x394/0x530
|  rcu_gp_kthread+0x76c/0x19a8
|  kthread+0x174/0x188
|  ret_from_fork+0x10/0x18
| 
| ================================
| WARNING: inconsistent lock state
| 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #18 Not tainted
| --------------------------------
| inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
| kcompactd0/26 [HC0[0]:SC0[0]:HE0:SE1] takes:
| ffffae32e6bd4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| {IN-HARDIRQ-W} state was registered at:
|   __lock_acquire+0x7bc/0x15b8
|   lock_acquire+0x244/0x498
|   _raw_spin_lock_irqsave+0x78/0x144
|   rcu_sched_clock_irq+0x4a0/0xd18
|   update_process_times+0x68/0x98
|   tick_sched_handle.isra.16+0x54/0x80
|   tick_sched_timer+0x64/0xd8
|   __hrtimer_run_queues+0x2a4/0x750
| [...]
| irq event stamp: 270278
| hardirqs last  enabled at (270277): [<ffffae32e5a0bff8>] _raw_spin_unlock_irq+0x48/0x90
| hardirqs last disabled at (270278): [<ffffae32e46122bc>] el1_irq+0x7c/0x180
| softirqs last  enabled at (268786): [<ffffae32e4610b58>] __do_softirq+0x650/0x6a4
| softirqs last disabled at (268783): [<ffffae32e46c0b80>] irq_exit+0x1a8/0x1b0
| 
| other info that might help us debug this:
|  Possible unsafe locking scenario:
| 
|        CPU0
|        ----
|   lock(rcu_node_0);
|   <Interrupt>
|     lock(rcu_node_0);
| 
|  *** DEADLOCK ***
| 
| 1 lock held by kcompactd0/26:
|  #0: ffffae32e6bd4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| [...]

Full log and config attached. Also, I can provoke this quicker with the attached diff.

Thanks,
-- Marco

[    0.000000] Booting Linux on physical CPU 0x0000000000 [0x411fd070]
[    0.000000] Linux version 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty ([email protected]) (aarch64-linux-gnu-gcc (Linaro GCC 7.4-2019.02) 7.4.1 20181213 [linaro-7.4-2019.02 revision 56ec6f6b99cc167ff0c2f8e1a2eed33b1edc85d4], GNU ld (Linaro_Binutils-2019.02) 2.28.2.20170706) #18 SMP PREEMPT Wed Nov 11 12:13:12 CET 2020
[    0.000000] Machine model: linux,dummy-virt
[    0.000000] efi: UEFI not found.
[    0.000000] cma: Reserved 32 MiB at 0x00000000be000000
[    0.000000] earlycon: pl11 at MMIO 0x0000000009000000 (options '')
[    0.000000] printk: bootconsole [pl11] enabled
[    0.000000] NUMA: No NUMA configuration found
[    0.000000] NUMA: Faking a node at [mem 0x0000000040000000-0x00000000bfffffff]
[    0.000000] NUMA: NODE_DATA [mem 0xbdbf8000-0xbdbf9fff]
[    0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x0000000040000000-0x00000000bfffffff]
[    0.000000]   DMA32    empty
[    0.000000]   Normal   empty
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000040000000-0x00000000bfffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000040000000-0x00000000bfffffff]
[    0.000000] On node 0 totalpages: 524288
[    0.000000]   DMA zone: 8192 pages used for memmap
[    0.000000]   DMA zone: 0 pages reserved
[    0.000000]   DMA zone: 524288 pages, LIFO batch:63
[    0.000000] psci: probing for conduit method from DT.
[    0.000000] psci: PSCIv0.2 detected in firmware.
[    0.000000] psci: Using standard PSCI v0.2 function IDs
[    0.000000] psci: Trusted OS migration not required
[    0.000000] percpu: Embedded 49 pages/cpu s161936 r8192 d30576 u200704
[    0.000000] pcpu-alloc: s161936 r8192 d30576 u200704 alloc=49*4096
[    0.000000] pcpu-alloc: [0] 0 
[    0.000000] Detected PIPT I-cache on CPU0
[    0.000000] CPU features: detected: ARM erratum 832075
[    0.000000] CPU features: detected: ARM erratum 834220
[    0.000000] CPU features: detected: EL2 vector hardening
[    0.000000] CPU features: kernel page table isolation forced ON by KASLR
[    0.000000] CPU features: detected: Kernel page table isolation (KPTI)
[    0.000000] CPU features: detected: Spectre-v2
[    0.000000] CPU features: detected: Spectre-v4
[    0.000000] CPU features: detected: ARM errata 1165522, 1319367, or 1530923
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 516096
[    0.000000] Policy zone: DMA
[    0.000000] Kernel command line: console=ttyAMA0 root=/dev/sda debug earlycon earlyprintk=serial slub_debug=UZ slub_debug=- kfence.sample_interval=0
[    0.000000] Dentry cache hash table entries: 262144 (order: 9, 2097152 bytes, linear)
[    0.000000] Inode-cache hash table entries: 131072 (order: 8, 1048576 bytes, linear)
[    0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
[    0.000000] Memory: 1969304K/2097152K available (20544K kernel code, 4020K rwdata, 8504K rodata, 8832K init, 11817K bss, 95080K reserved, 32768K cma-reserved)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[    0.000000] ftrace: allocating 56112 entries in 220 pages
[    0.000000] ftrace: allocated 220 pages with 5 groups
[    0.000000] Running RCU self tests
[    0.000000] rcu: Preemptible hierarchical RCU implementation.
[    0.000000] rcu: 	RCU event tracing is enabled.
[    0.000000] rcu: 	RCU lockdep checking is enabled.
[    0.000000] rcu: 	RCU restricting CPUs from NR_CPUS=256 to nr_cpu_ids=1.
[    0.000000] 	Trampoline variant of Tasks RCU enabled.
[    0.000000] 	Rude variant of Tasks RCU enabled.
[    0.000000] 	Tracing variant of Tasks RCU enabled.
[    0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 25 jiffies.
[    0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=1
[    0.000000] NR_IRQS: 64, nr_irqs: 64, preallocated irqs: 0
[    0.000000] GICv2m: range[mem 0x08020000-0x08020fff], SPI[80:143]
[    0.000000] random: get_random_bytes called from start_kernel+0x428/0x5e8 with crng_init=0
[    0.000000] arch_timer: cp15 timer(s) running at 62.50MHz (virt).
[    0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x1cd42e208c, max_idle_ns: 881590405314 ns
[    0.000233] sched_clock: 56 bits at 62MHz, resolution 16ns, wraps every 4398046511096ns
[    0.011426] Console: colour dummy device 80x25
[    0.012862] Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar
[    0.013209] ... MAX_LOCKDEP_SUBCLASSES:  8
[    0.013469] ... MAX_LOCK_DEPTH:          48
[    0.013728] ... MAX_LOCKDEP_KEYS:        8192
[    0.013992] ... CLASSHASH_SIZE:          4096
[    0.014251] ... MAX_LOCKDEP_ENTRIES:     32768
[    0.014511] ... MAX_LOCKDEP_CHAINS:      65536
[    0.014770] ... CHAINHASH_SIZE:          32768
[    0.015031]  memory used by lock dependency info: 6365 kB
[    0.015306]  memory used for stack traces: 4224 kB
[    0.015573]  per task-struct memory footprint: 1920 bytes
[    0.018216] Calibrating delay loop (skipped), value calculated using timer frequency.. 125.00 BogoMIPS (lpj=250000)
[    0.018900] pid_max: default: 32768 minimum: 301
[    0.022123] LSM: Security Framework initializing
[    0.024372] Mount-cache hash table entries: 4096 (order: 3, 32768 bytes, linear)
[    0.025621] Mountpoint-cache hash table entries: 4096 (order: 3, 32768 bytes, linear)
[    0.113947] rcu: Hierarchical SRCU implementation.
[    0.133436] EFI services will not be available.
[    0.137866] smp: Bringing up secondary CPUs ...
[    0.138333] smp: Brought up 1 node, 1 CPU
[    0.138982] SMP: Total of 1 processors activated.
[    0.139442] CPU features: detected: 32-bit EL0 Support
[    0.139873] CPU features: detected: CRC32 instructions
[    0.140211] CPU features: detected: 32-bit EL1 Support
[    0.533739] CPU: All CPU(s) started at EL1
[    0.534735] alternatives: patching kernel code
[    0.597327] devtmpfs: initialized
[    0.671951] KASLR enabled
[    0.702419] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns
[    0.703467] futex hash table entries: 256 (order: 3, 32768 bytes, linear)
[    0.705355] Running postponed tracer tests:
[    0.709250] Testing tracer function: PASSED
[    8.480905] Testing dynamic ftrace: PASSED
[    9.425085] Testing dynamic ftrace ops #1: 
[   12.011706] (1 0 1 0 0) 
[   12.012472] (1 1 2 0 0) 
[   19.421411] (2 1 3 0 1101335) 
[   19.423966] (2 2 4 0 1101760) PASSED
[   23.382135] Testing dynamic ftrace ops #2: 
[   32.872265] (1 0 1 1082126 0) 
[   32.873599] (1 1 2 1082338 0) 
[   32.924413] (2 1 3 1 2103) 
[   32.925559] (2 2 4 200 2302) PASSED
[   36.124900] Testing ftrace recursion: PASSED
[   36.859157] Testing ftrace recursion safe: PASSED
[   37.594606] Testing ftrace regs(no arch support): PASSED
[   38.333537] Testing tracer nop: PASSED
[   38.337880] Testing tracer irqsoff: PASSED
[   46.271584] Testing tracer preemptoff: PASSED
[   54.135978] Testing tracer preemptirqsoff: PASSED
[   62.043008] Testing tracer wakeup: 
[   67.158358] sched: DL replenish lagged too much
[   69.851230] PASSED
[   69.859014] Testing tracer wakeup_rt: PASSED
[   77.691853] Testing tracer wakeup_dl: PASSED
[   85.583156] Testing tracer function_graph: PASSED
[   93.250201] pinctrl core: initialized pinctrl subsystem
[   93.297588] DMI not present or invalid.
[   93.317875] NET: Registered protocol family 16
[   93.384841] DMA: preallocated 256 KiB GFP_KERNEL pool for atomic allocations
[   93.385798] DMA: preallocated 256 KiB GFP_KERNEL|GFP_DMA pool for atomic allocations
[   93.388668] DMA: preallocated 256 KiB GFP_KERNEL|GFP_DMA32 pool for atomic allocations
[   93.390895] audit: initializing netlink subsys (disabled)
[   93.402708] audit: type=2000 audit(81.888:1): state=initialized audit_enabled=0 res=1
[   93.438512] thermal_sys: Registered thermal governor 'step_wise'
[   93.438744] thermal_sys: Registered thermal governor 'power_allocator'
[   93.442047] cpuidle: using governor menu
[   93.447969] hw-breakpoint: found 6 breakpoint and 4 watchpoint registers.
[   93.449661] ASID allocator initialised with 32768 entries
[   93.485107] Serial: AMBA PL011 UART driver
[   94.434483] 9000000.pl011: ttyAMA0 at MMIO 0x9000000 (irq = 47, base_baud = 0) is a PL011 rev1
[   94.438214] printk: console [ttyAMA0] enabled
[   94.438214] printk: console [ttyAMA0] enabled
[   94.439358] printk: bootconsole [pl11] disabled
[   94.439358] printk: bootconsole [pl11] disabled
[   94.922239] HugeTLB registered 1.00 GiB page size, pre-allocated 0 pages
[   94.922762] HugeTLB registered 32.0 MiB page size, pre-allocated 0 pages
[   94.923519] HugeTLB registered 2.00 MiB page size, pre-allocated 0 pages
[   94.923960] HugeTLB registered 64.0 KiB page size, pre-allocated 0 pages
[   94.995847] cryptd: max_cpu_qlen set to 1000
[   95.132486] ACPI: Interpreter disabled.
[   95.198275] iommu: Default domain type: Translated 
[   95.207497] vgaarb: loaded
[   95.219386] SCSI subsystem initialized
[   95.224642] libata version 3.00 loaded.
[   95.233901] usbcore: registered new interface driver usbfs
[   95.235586] usbcore: registered new interface driver hub
[   95.237847] usbcore: registered new device driver usb
[   95.262747] pps_core: LinuxPPS API ver. 1 registered
[   95.263152] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <[email protected]>
[   95.263966] PTP clock support registered
[   95.269799] EDAC MC: Ver: 3.0.0
[   95.324422] FPGA manager framework
[   95.328570] Advanced Linux Sound Architecture Driver Initialized.
[   95.361928] clocksource: Switched to clocksource arch_sys_counter
[  111.416735] VFS: Disk quotas dquot_6.6.0
[  111.418925] VFS: Dquot-cache hash table entries: 512 (order 0, 4096 bytes)
[  111.428393] pnp: PnP ACPI: disabled
[  111.666757] NET: Registered protocol family 2
[  111.690777] tcp_listen_portaddr_hash hash table entries: 1024 (order: 4, 81920 bytes, linear)
[  111.691885] TCP established hash table entries: 16384 (order: 5, 131072 bytes, linear)
[  111.701171] TCP bind hash table entries: 16384 (order: 8, 1179648 bytes, linear)
[  111.708874] TCP: Hash tables configured (established 16384 bind 16384)
[  111.713132] UDP hash table entries: 1024 (order: 5, 163840 bytes, linear)
[  111.716578] UDP-Lite hash table entries: 1024 (order: 5, 163840 bytes, linear)
[  111.722527] NET: Registered protocol family 1
[  111.740889] RPC: Registered named UNIX socket transport module.
[  111.741847] RPC: Registered udp transport module.
[  111.742250] RPC: Registered tcp transport module.
[  111.742627] RPC: Registered tcp NFSv4.1 backchannel transport module.
[  111.743235] PCI: CLS 0 bytes, default 64
[  111.773814] hw perfevents: enabled with armv8_pmuv3 PMU driver, 5 counters available
[  111.775981] kvm [1]: HYP mode not available
[  112.002354] Initialise system trusted keyrings
[  112.008369] workingset: timestamp_bits=44 max_order=19 bucket_order=0
[  112.315870] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[  112.336509] NFS: Registering the id_resolver key type
[  112.337956] Key type id_resolver registered
[  112.338516] Key type id_legacy registered
[  112.342326] nfs4filelayout_init: NFSv4 File Layout Driver Registering...
[  112.350262] 9p: Installing v9fs 9p2000 file system support
[  112.445768] Key type asymmetric registered
[  112.446387] Asymmetric key parser 'x509' registered
[  112.447763] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 245)
[  112.448420] io scheduler mq-deadline registered
[  112.448928] io scheduler kyber registered
[  112.832673] pl061_gpio 9030000.pl061: PL061 GPIO chip registered
[  112.892911] pci-host-generic 4010000000.pcie: host bridge /pcie@10000000 ranges:
[  112.895334] pci-host-generic 4010000000.pcie:       IO 0x003eff0000..0x003effffff -> 0x0000000000
[  112.897242] pci-host-generic 4010000000.pcie:      MEM 0x0010000000..0x003efeffff -> 0x0010000000
[  112.898516] pci-host-generic 4010000000.pcie:      MEM 0x8000000000..0xffffffffff -> 0x8000000000
[  112.901413] pci-host-generic 4010000000.pcie: ECAM at [mem 0x4010000000-0x401fffffff] for [bus 00-ff]
[  112.906977] pci-host-generic 4010000000.pcie: PCI host bridge to bus 0000:00
[  112.907704] pci_bus 0000:00: root bus resource [bus 00-ff]
[  112.908246] pci_bus 0000:00: root bus resource [io  0x0000-0xffff]
[  112.908735] pci_bus 0000:00: root bus resource [mem 0x10000000-0x3efeffff]
[  112.909295] pci_bus 0000:00: root bus resource [mem 0x8000000000-0xffffffffff]
[  112.912394] pci 0000:00:00.0: [1b36:0008] type 00 class 0x060000
[  112.924053] pci 0000:00:01.0: [1af4:1009] type 00 class 0x000200
[  112.925272] pci 0000:00:01.0: reg 0x10: [io  0x0000-0x003f]
[  112.926292] pci 0000:00:01.0: reg 0x14: [mem 0x00000000-0x00000fff]
[  112.927523] pci 0000:00:01.0: reg 0x20: [mem 0x00000000-0x00003fff 64bit pref]
[  112.935594] pci 0000:00:02.0: [1af4:1009] type 00 class 0x000200
[  112.936480] pci 0000:00:02.0: reg 0x10: [io  0x0000-0x003f]
[  112.937116] pci 0000:00:02.0: reg 0x14: [mem 0x00000000-0x00000fff]
[  112.938606] pci 0000:00:02.0: reg 0x20: [mem 0x00000000-0x00003fff 64bit pref]
[  112.946673] pci 0000:00:03.0: [1af4:1000] type 00 class 0x020000
[  112.947572] pci 0000:00:03.0: reg 0x10: [io  0x0000-0x001f]
[  112.948199] pci 0000:00:03.0: reg 0x14: [mem 0x00000000-0x00000fff]
[  112.949374] pci 0000:00:03.0: reg 0x20: [mem 0x00000000-0x00003fff 64bit pref]
[  112.950357] pci 0000:00:03.0: reg 0x30: [mem 0x00000000-0x0003ffff pref]
[  112.958217] pci 0000:00:04.0: [1af4:1004] type 00 class 0x010000
[  112.959101] pci 0000:00:04.0: reg 0x10: [io  0x0000-0x003f]
[  112.959728] pci 0000:00:04.0: reg 0x14: [mem 0x00000000-0x00000fff]
[  112.960876] pci 0000:00:04.0: reg 0x20: [mem 0x00000000-0x00003fff 64bit pref]
[  112.974853] pci 0000:00:03.0: BAR 6: assigned [mem 0x10000000-0x1003ffff pref]
[  112.975676] pci 0000:00:01.0: BAR 4: assigned [mem 0x8000000000-0x8000003fff 64bit pref]
[  112.976651] pci 0000:00:02.0: BAR 4: assigned [mem 0x8000004000-0x8000007fff 64bit pref]
[  112.977889] pci 0000:00:03.0: BAR 4: assigned [mem 0x8000008000-0x800000bfff 64bit pref]
[  112.978725] pci 0000:00:04.0: BAR 4: assigned [mem 0x800000c000-0x800000ffff 64bit pref]
[  112.979501] pci 0000:00:01.0: BAR 1: assigned [mem 0x10040000-0x10040fff]
[  112.980096] pci 0000:00:02.0: BAR 1: assigned [mem 0x10041000-0x10041fff]
[  112.980678] pci 0000:00:03.0: BAR 1: assigned [mem 0x10042000-0x10042fff]
[  112.981246] pci 0000:00:04.0: BAR 1: assigned [mem 0x10043000-0x10043fff]
[  112.982177] pci 0000:00:01.0: BAR 0: assigned [io  0x1000-0x103f]
[  112.982760] pci 0000:00:02.0: BAR 0: assigned [io  0x1040-0x107f]
[  112.983316] pci 0000:00:04.0: BAR 0: assigned [io  0x1080-0x10bf]
[  112.983869] pci 0000:00:03.0: BAR 0: assigned [io  0x10c0-0x10df]
[  113.057252] EINJ: ACPI disabled.
[  113.556321] virtio-pci 0000:00:01.0: enabling device (0000 -> 0003)
[  113.571711] virtio-pci 0000:00:02.0: enabling device (0000 -> 0003)
[  113.584925] virtio-pci 0000:00:03.0: enabling device (0000 -> 0003)
[  113.596020] virtio-pci 0000:00:04.0: enabling device (0000 -> 0003)
[  113.787453] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[  113.882178] SuperH (H)SCI(F) driver initialized
[  113.901072] msm_serial: driver initialized
[  113.952925] cacheinfo: Unable to detect cache hierarchy for CPU 0
[  114.230176] loop: module loaded
[  114.262318] megasas: 07.714.04.00-rc1
[  114.302236] scsi host0: Virtio SCSI HBA
[  114.336019] scsi 0:0:0:0: Direct-Access     QEMU     QEMU HARDDISK    2.5+ PQ: 0 ANSI: 5
[  117.142680] random: fast init done
[  117.213261] sd 0:0:0:0: Power-on or device reset occurred
[  117.238425] sd 0:0:0:0: [sda] 524288 512-byte logical blocks: (268 MB/256 MiB)
[  117.240745] sd 0:0:0:0: [sda] Write Protect is off
[  117.241797] sd 0:0:0:0: [sda] Mode Sense: 63 00 00 08
[  117.245029] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[  117.363810] physmap-flash 0.flash: physmap platform flash device: [mem 0x00000000-0x03ffffff]
[  117.370560] 0.flash: Found 2 x16 devices at 0x0 in 32-bit bank. Manufacturer ID 0x000000 Chip ID 0x000000
[  117.371615] Intel/Sharp Extended Query Table at 0x0031
[  117.372904] Using buffer write method
[  117.378232] erase region 0: offset=0x0,size=0x40000,blocks=256
[  117.379270] physmap-flash 0.flash: physmap platform flash device: [mem 0x04000000-0x07ffffff]
[  117.386159] 0.flash: Found 2 x16 devices at 0x0 in 32-bit bank. Manufacturer ID 0x000000 Chip ID 0x000000
[  117.386764] Intel/Sharp Extended Query Table at 0x0031
[  117.387780] Using buffer write method
[  117.388252] erase region 0: offset=0x0,size=0x40000,blocks=256
[  117.388744] Concatenating MTD devices:
[  117.389145] (0): "0.flash"
[  117.394228] (1): "0.flash"
[  117.394599] into device "0.flash"
[  117.431485] sd 0:0:0:0: [sda] Attached SCSI disk
[  117.647630] libphy: Fixed MDIO Bus: probed
[  117.695782] tun: Universal TUN/TAP device driver, 1.6
[  117.753377] thunder_xcv, ver 1.0
[  117.755546] thunder_bgx, ver 1.0
[  117.757381] nicpf, ver 1.0
[  117.802859] hclge is initializing
[  117.804122] hns3: Hisilicon Ethernet Network Driver for Hip08 Family - version
[  117.804571] hns3: Copyright (c) 2017 Huawei Corporation.
[  117.807038] e1000: Intel(R) PRO/1000 Network Driver
[  117.807436] e1000: Copyright (c) 1999-2006 Intel Corporation.
[  117.809232] e1000e: Intel(R) PRO/1000 Network Driver
[  117.809943] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
[  117.811895] igb: Intel(R) Gigabit Ethernet Network Driver
[  117.812296] igb: Copyright (c) 2007-2014 Intel Corporation.
[  117.814130] igbvf: Intel(R) Gigabit Virtual Function Network Driver
[  117.814551] igbvf: Copyright (c) 2009 - 2012 Intel Corporation.
[  117.828957] sky2: driver version 1.30
[  117.865333] VFIO - User Level meta-driver version: 0.3
[  117.930121] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[  117.930624] ehci-pci: EHCI PCI platform driver
[  117.932133] ehci-platform: EHCI generic platform driver
[  117.936936] ehci-orion: EHCI orion driver
[  117.941876] ehci-exynos: EHCI Exynos driver
[  117.946441] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
[  117.947298] ohci-pci: OHCI PCI platform driver
[  117.948921] ohci-platform: OHCI generic platform driver
[  117.954091] ohci-exynos: OHCI Exynos driver
[  117.970958] usbcore: registered new interface driver usb-storage
[  118.086591] rtc-pl031 9010000.pl031: registered as rtc0
[  118.088263] rtc-pl031 9010000.pl031: setting system clock to 2020-11-11T11:15:44 UTC (1605093344)
[  118.112352] i2c /dev entries driver
[  118.359637] sdhci: Secure Digital Host Controller Interface driver
[  118.360055] sdhci: Copyright(c) Pierre Ossman
[  118.376774] Synopsys Designware Multimedia Card Interface Driver
[  118.417048] sdhci-pltfm: SDHCI platform and OF driver helper
[  118.473048] ledtrig-cpu: registered to indicate activity on CPUs
[  118.541154] usbcore: registered new interface driver usbhid
[  118.541908] usbhid: USB HID core driver
[  118.726391] drop_monitor: Initializing network drop monitor service
[  118.729987] NET: Registered protocol family 17
[  118.736719] 9pnet: Installing 9P2000 support
[  118.755745] Key type dns_resolver registered
[  118.763199] registered taskstats version 1
[  118.764943] Running tests on all trace events:
[  118.765319] Testing all events: OK
[  154.077275] hrtimer: interrupt took 21125232 ns
[  176.049337] Running tests again, along with the function tracer
[  176.068194] Running tests on all trace events:
[  176.078196] Testing all events: 
[ 1320.629571] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 32s!
[ 1320.785660] Showing busy workqueues and worker pools:
[ 1320.825476] workqueue events: flags=0x0
[ 1320.861955]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
[ 1320.873397]     pending: vmstat_shepherd
[ 1320.885467] workqueue events_power_efficient: flags=0x82
[ 1320.921575]   pwq 2: cpus=0 flags=0x5 nice=0 active=2/256 refcnt=4
[ 1320.931385]     in-flight: 107:neigh_periodic_work
[ 1320.938581]     pending: do_cache_clean
[ 1320.960212] pool 2: cpus=0 flags=0x5 nice=0 hung=3s workers=2 manager: 7
[ 2535.539509] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
[ 2535.545633] 	(detected by 0, t=6502 jiffies, g=2885, q=4)
[ 2535.547634] rcu: All QSes seen, last rcu_preempt kthread activity 5174 (4295523265-4295518091), jiffies_till_next_fqs=1, root ->qsmask 0x0
[ 2535.558720] rcu: rcu_preempt kthread starved for 5174 jiffies! g2885 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
[ 2535.564713] rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
[ 2535.570363] rcu: RCU grace-period kthread stack dump:
[ 2535.574930] task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
[ 2535.584170] Call trace:
[ 2535.588004]  __switch_to+0x100/0x1e0
[ 2535.592125]  __schedule+0x2d0/0x890
[ 2535.596252]  preempt_schedule_notrace+0x70/0x1c0
[ 2535.600745]  ftrace_ops_no_ops+0x174/0x250
[ 2535.605047]  ftrace_graph_call+0x0/0xc
[ 2535.609205]  preempt_count_add+0x1c/0x180
[ 2535.613451]  schedule+0x44/0x108
[ 2535.617464]  schedule_timeout+0x394/0x530
[ 2535.621741]  rcu_gp_kthread+0x76c/0x19a8
[ 2535.625972]  kthread+0x174/0x188
[ 2535.630006]  ret_from_fork+0x10/0x18
[ 2535.643477] 
[ 2535.645825] ================================
[ 2535.648864] WARNING: inconsistent lock state
[ 2535.652090] 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #18 Not tainted
[ 2535.656024] --------------------------------
[ 2535.659086] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
[ 2535.662702] kcompactd0/26 [HC0[0]:SC0[0]:HE0:SE1] takes:
[ 2535.666132] ffffae32e6bd4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
[ 2535.674157] {IN-HARDIRQ-W} state was registered at:
[ 2535.677571]   __lock_acquire+0x7bc/0x15b8
[ 2535.680656]   lock_acquire+0x244/0x498
[ 2535.683628]   _raw_spin_lock_irqsave+0x78/0x144
[ 2535.686822]   rcu_sched_clock_irq+0x4a0/0xd18
[ 2535.689963]   update_process_times+0x68/0x98
[ 2535.693072]   tick_sched_handle.isra.16+0x54/0x80
[ 2535.696314]   tick_sched_timer+0x64/0xd8
[ 2535.699352]   __hrtimer_run_queues+0x2a4/0x750
[ 2535.702522]   hrtimer_interrupt+0xf4/0x2a0
[ 2535.705620]   arch_timer_handler_virt+0x44/0x70
[ 2535.708845]   handle_percpu_devid_irq+0xfc/0x4d0
[ 2535.712056]   generic_handle_irq+0x50/0x70
[ 2535.715127]   __handle_domain_irq+0x9c/0x120
[ 2535.718233]   gic_handle_irq+0xcc/0x108
[ 2535.721261]   el1_irq+0xbc/0x180
[ 2535.724080]   _raw_spin_unlock_irq+0x50/0x90
[ 2535.727203]   finish_task_switch+0xa4/0x2a8
[ 2535.730289]   __schedule+0x2d4/0x890
[ 2535.733211]   preempt_schedule_notrace+0x70/0x1c0
[ 2535.736450]   ftrace_ops_no_ops+0x174/0x250
[ 2535.739535]   ftrace_graph_call+0x0/0xc
[ 2535.742555]   preempt_count_add+0x1c/0x180
[ 2535.745621]   schedule+0x44/0x108
[ 2535.748470]   schedule_timeout+0x394/0x530
[ 2535.751548]   kcompactd+0x340/0x498
[ 2535.754446]   kthread+0x174/0x188
[ 2535.757308]   ret_from_fork+0x10/0x18
[ 2535.760211] irq event stamp: 270278
[ 2535.763168] hardirqs last  enabled at (270277): [<ffffae32e5a0bff8>] _raw_spin_unlock_irq+0x48/0x90
[ 2535.767704] hardirqs last disabled at (270278): [<ffffae32e46122bc>] el1_irq+0x7c/0x180
[ 2535.771957] softirqs last  enabled at (268786): [<ffffae32e4610b58>] __do_softirq+0x650/0x6a4
[ 2535.776321] softirqs last disabled at (268783): [<ffffae32e46c0b80>] irq_exit+0x1a8/0x1b0
[ 2535.780515] 
[ 2535.780515] other info that might help us debug this:
[ 2535.784227]  Possible unsafe locking scenario:
[ 2535.784227] 
[ 2535.787754]        CPU0
[ 2535.790268]        ----
[ 2535.792772]   lock(rcu_node_0);
[ 2535.797232]   <Interrupt>
[ 2535.799765]     lock(rcu_node_0);
[ 2535.804266] 
[ 2535.804266]  *** DEADLOCK ***
[ 2535.804266] 
[ 2535.807836] 1 lock held by kcompactd0/26:
[ 2535.810840]  #0: ffffae32e6bd4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
[ 2535.819708] 
[ 2535.819708] stack backtrace:
[ 2535.823059] CPU: 0 PID: 26 Comm: kcompactd0 Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #18
[ 2535.827790] Hardware name: linux,dummy-virt (DT)
[ 2535.831009] Call trace:
[ 2535.833607]  dump_backtrace+0x0/0x278
[ 2535.836537]  show_stack+0x30/0x80
[ 2535.839386]  dump_stack+0x138/0x1b0
[ 2535.842278]  print_usage_bug+0x2d8/0x2f8
[ 2535.845301]  mark_lock.part.46+0x370/0x480
[ 2535.848366]  mark_held_locks+0x58/0x90
[ 2535.851340]  lockdep_hardirqs_on_prepare+0xdc/0x298
[ 2535.854655]  trace_hardirqs_on+0x90/0x388
[ 2535.857693]  el1_irq+0xd8/0x180
[ 2535.860494]  _raw_spin_unlock_irq+0x50/0x90
[ 2535.863583]  finish_task_switch+0xa4/0x2a8
[ 2535.866656]  __schedule+0x2d4/0x890
[ 2535.869575]  preempt_schedule_notrace+0x70/0x1c0
[ 2535.872811]  ftrace_ops_no_ops+0x174/0x250
[ 2535.875885]  ftrace_graph_call+0x0/0xc
[ 2535.878865]  preempt_count_add+0x1c/0x180
[ 2535.881901]  schedule+0x44/0x108
[ 2535.884719]  schedule_timeout+0x394/0x530
[ 2535.887747]  kcompactd+0x340/0x498
[ 2535.890630]  kthread+0x174/0x188
[ 2535.893441]  ret_from_fork+0x10/0x18
[ 2535.900455] BUG: scheduling while atomic: kcompactd0/26/0x00000002
[ 2535.908864] INFO: lockdep is turned off.
[ 2535.917408] Modules linked in:
[ 2535.930517] Preemption disabled at:
[ 2535.932175] [<ffffae32e4819ca4>] ftrace_ops_no_ops+0x174/0x250
[ 2535.945072] CPU: 0 PID: 26 Comm: kcompactd0 Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #18
[ 2535.949821] Hardware name: linux,dummy-virt (DT)
[ 2535.952991] Call trace:
[ 2535.955591]  dump_backtrace+0x0/0x278
[ 2535.958529]  show_stack+0x30/0x80
[ 2535.961385]  dump_stack+0x138/0x1b0
[ 2535.964320]  __schedule_bug+0x8c/0xe8
[ 2535.967292]  __schedule+0x7e8/0x890
[ 2535.970204]  preempt_schedule_notrace+0x70/0x1c0
[ 2535.973465]  ftrace_ops_no_ops+0x174/0x250
[ 2535.976547]  ftrace_graph_call+0x0/0xc
[ 2535.979553]  preempt_count_add+0x1c/0x180
[ 2535.982597]  schedule+0x44/0x108
[ 2535.985411]  schedule_timeout+0x394/0x530
[ 2535.988445]  kcompactd+0x340/0x498
[ 2535.991330]  kthread+0x174/0x188
[ 2535.994150]  ret_from_fork+0x10/0x18

qemu-system-aarch64: terminating on signal 15 from pid 4135918 ()

kernel/trace/trace_events.c +2 -0

index 47a71f96e5bc..2fbe0637e053 100644
@@ -3568,6 +3568,7 @@ static __init void event_trace_self_tests(void)
 	if (!tr)
 		return;
 
+#if 0
 	pr_info("Running tests on trace events:\n");
 
 	list_for_each_entry(file, &tr->events, list) {

@@ -3641,6 +3642,7 @@ static __init void event_trace_self_tests(void)
 
 		pr_cont("OK\n");
 	}
+#endif
 
 	/* Test with all events enabled */

#
# Automatically generated file; DO NOT EDIT.
# Linux/arm64 5.10.0-rc3 Kernel Configuration
#
CONFIG_CC_VERSION_TEXT="aarch64-linux-gnu-gcc (Linaro GCC 7.4-2019.02) 7.4.1 20181213 [linaro-7.4-2019.02 revision 56ec6f6b99cc167ff0c2f8e1a2eed33b1edc85d4]" CONFIG_CC_IS_GCC=y
CONFIG_GCC_VERSION=70401
CONFIG_LD_VERSION=228020000
CONFIG_CLANG_VERSION=0
CONFIG_CC_CAN_LINK=y
CONFIG_CC_CAN_LINK_STATIC=y
CONFIG_CC_HAS_ASM_GOTO=y
CONFIG_IRQ_WORK=y
CONFIG_BUILDTIME_TABLE_SORT=y
CONFIG_THREAD_INFO_IN_TASK=y

#
# General setup
#
CONFIG_INIT_ENV_ARG_LIMIT=32
# CONFIG_COMPILE_TEST is not set
CONFIG_LOCALVERSION=""
CONFIG_LOCALVERSION_AUTO=y
CONFIG_BUILD_SALT=""
CONFIG_DEFAULT_INIT=""
CONFIG_DEFAULT_HOSTNAME="(none)"
CONFIG_SWAP=y
CONFIG_SYSVIPC=y
CONFIG_SYSVIPC_SYSCTL=y
CONFIG_POSIX_MQUEUE=y
CONFIG_POSIX_MQUEUE_SYSCTL=y
# CONFIG_WATCH_QUEUE is not set
CONFIG_CROSS_MEMORY_ATTACH=y
# CONFIG_USELIB is not set
CONFIG_AUDIT=y
CONFIG_HAVE_ARCH_AUDITSYSCALL=y
CONFIG_AUDITSYSCALL=y

#
# IRQ subsystem
#
CONFIG_GENERIC_IRQ_PROBE=y
CONFIG_GENERIC_IRQ_SHOW=y
CONFIG_GENERIC_IRQ_SHOW_LEVEL=y
CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK=y
CONFIG_GENERIC_IRQ_MIGRATION=y
CONFIG_HARDIRQS_SW_RESEND=y
CONFIG_GENERIC_IRQ_CHIP=y
CONFIG_IRQ_DOMAIN=y
CONFIG_IRQ_DOMAIN_HIERARCHY=y
CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS=y
CONFIG_GENERIC_IRQ_IPI=y
CONFIG_GENERIC_MSI_IRQ=y
CONFIG_GENERIC_MSI_IRQ_DOMAIN=y
CONFIG_IRQ_MSI_IOMMU=y
CONFIG_HANDLE_DOMAIN_IRQ=y
CONFIG_IRQ_FORCED_THREADING=y
CONFIG_SPARSE_IRQ=y
# CONFIG_GENERIC_IRQ_DEBUGFS is not set

# end of IRQ subsystem

CONFIG_GENERIC_IRQ_MULTI_HANDLER=y
CONFIG_GENERIC_TIME_VSYSCALL=y
CONFIG_GENERIC_CLOCKEVENTS=y
CONFIG_ARCH_HAS_TICK_BROADCAST=y
CONFIG_GENERIC_CLOCKEVENTS_BROADCAST=y

#
# Timers subsystem
#
CONFIG_TICK_ONESHOT=y
CONFIG_NO_HZ_COMMON=y
# CONFIG_HZ_PERIODIC is not set
CONFIG_NO_HZ_IDLE=y
# CONFIG_NO_HZ_FULL is not set
# CONFIG_NO_HZ is not set
CONFIG_HIGH_RES_TIMERS=y

# end of Timers subsystem

# CONFIG_PREEMPT_NONE is not set
# CONFIG_PREEMPT_VOLUNTARY is not set
CONFIG_PREEMPT=y
CONFIG_PREEMPTION=y

#
# CPU/Task time and stats accounting
#
CONFIG_TICK_CPU_ACCOUNTING=y
# CONFIG_VIRT_CPU_ACCOUNTING_GEN is not set
CONFIG_IRQ_TIME_ACCOUNTING=y
CONFIG_HAVE_SCHED_AVG_IRQ=y
CONFIG_SCHED_THERMAL_PRESSURE=y
CONFIG_BSD_PROCESS_ACCT=y
CONFIG_BSD_PROCESS_ACCT_V3=y
CONFIG_TASKSTATS=y
CONFIG_TASK_DELAY_ACCT=y
CONFIG_TASK_XACCT=y
CONFIG_TASK_IO_ACCOUNTING=y
# CONFIG_PSI is not set

# end of CPU/Task time and stats accounting

CONFIG_CPU_ISOLATION=y

#
# RCU Subsystem
#
CONFIG_TREE_RCU=y
CONFIG_PREEMPT_RCU=y
# CONFIG_RCU_EXPERT is not set
CONFIG_SRCU=y
CONFIG_TREE_SRCU=y
CONFIG_TASKS_RCU_GENERIC=y
CONFIG_TASKS_RCU=y
CONFIG_TASKS_RUDE_RCU=y
CONFIG_TASKS_TRACE_RCU=y
CONFIG_RCU_STALL_COMMON=y
CONFIG_RCU_NEED_SEGCBLIST=y

# end of RCU Subsystem

CONFIG_IKCONFIG=y
CONFIG_IKCONFIG_PROC=y
# CONFIG_IKHEADERS is not set
CONFIG_LOG_BUF_SHIFT=17
CONFIG_LOG_CPU_MAX_BUF_SHIFT=12
CONFIG_PRINTK_SAFE_LOG_BUF_SHIFT=13
CONFIG_GENERIC_SCHED_CLOCK=y

#
# Scheduler features
#
# CONFIG_UCLAMP_TASK is not set

# end of Scheduler features

CONFIG_ARCH_SUPPORTS_NUMA_BALANCING=y
CONFIG_CC_HAS_INT128=y
CONFIG_ARCH_SUPPORTS_INT128=y
CONFIG_NUMA_BALANCING=y
CONFIG_NUMA_BALANCING_DEFAULT_ENABLED=y
CONFIG_CGROUPS=y
CONFIG_PAGE_COUNTER=y
CONFIG_MEMCG=y
CONFIG_MEMCG_SWAP=y
CONFIG_MEMCG_KMEM=y
CONFIG_BLK_CGROUP=y
CONFIG_CGROUP_WRITEBACK=y
CONFIG_CGROUP_SCHED=y
CONFIG_FAIR_GROUP_SCHED=y
# CONFIG_CFS_BANDWIDTH is not set
# CONFIG_RT_GROUP_SCHED is not set
CONFIG_CGROUP_PIDS=y
# CONFIG_CGROUP_RDMA is not set
# CONFIG_CGROUP_FREEZER is not set
CONFIG_CGROUP_HUGETLB=y
CONFIG_CPUSETS=y
CONFIG_PROC_PID_CPUSET=y
CONFIG_CGROUP_DEVICE=y
CONFIG_CGROUP_CPUACCT=y
CONFIG_CGROUP_PERF=y
# CONFIG_CGROUP_DEBUG is not set
CONFIG_NAMESPACES=y
CONFIG_UTS_NS=y
CONFIG_TIME_NS=y
CONFIG_IPC_NS=y
CONFIG_USER_NS=y
CONFIG_PID_NS=y
CONFIG_NET_NS=y
# CONFIG_CHECKPOINT_RESTORE is not set
CONFIG_SCHED_AUTOGROUP=y
# CONFIG_SYSFS_DEPRECATED is not set
CONFIG_RELAY=y
CONFIG_BLK_DEV_INITRD=y
CONFIG_INITRAMFS_SOURCE=""
CONFIG_RD_GZIP=y
CONFIG_RD_BZIP2=y
CONFIG_RD_LZMA=y
CONFIG_RD_XZ=y
CONFIG_RD_LZO=y
CONFIG_RD_LZ4=y
CONFIG_RD_ZSTD=y
# CONFIG_BOOT_CONFIG is not set
CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE=y
# CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
CONFIG_SYSCTL=y
CONFIG_HAVE_UID16=y
CONFIG_SYSCTL_EXCEPTION_TRACE=y
CONFIG_BPF=y
# CONFIG_EXPERT is not set
CONFIG_UID16=y
CONFIG_MULTIUSER=y
CONFIG_SYSFS_SYSCALL=y
CONFIG_FHANDLE=y
CONFIG_POSIX_TIMERS=y
CONFIG_PRINTK=y
CONFIG_PRINTK_NMI=y
CONFIG_BUG=y
CONFIG_ELF_CORE=y
CONFIG_BASE_FULL=y
CONFIG_FUTEX=y
CONFIG_FUTEX_PI=y
CONFIG_HAVE_FUTEX_CMPXCHG=y
CONFIG_EPOLL=y
CONFIG_SIGNALFD=y
CONFIG_TIMERFD=y
CONFIG_EVENTFD=y
CONFIG_SHMEM=y
CONFIG_AIO=y
CONFIG_IO_URING=y
CONFIG_ADVISE_SYSCALLS=y
CONFIG_MEMBARRIER=y
CONFIG_KALLSYMS=y
CONFIG_KALLSYMS_ALL=y
CONFIG_KALLSYMS_BASE_RELATIVE=y
# CONFIG_BPF_SYSCALL is not set
CONFIG_ARCH_WANT_DEFAULT_BPF_JIT=y
CONFIG_BPF_JIT_DEFAULT_ON=y
# CONFIG_USERFAULTFD is not set
CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE=y
CONFIG_RSEQ=y
# CONFIG_EMBEDDED is not set
CONFIG_HAVE_PERF_EVENTS=y

#
# Kernel Performance Events And Counters
#
CONFIG_PERF_EVENTS=y
# CONFIG_DEBUG_PERF_USE_VMALLOC is not set

# end of Kernel Performance Events And Counters

CONFIG_VM_EVENT_COUNTERS=y
CONFIG_SLUB_DEBUG=y
# CONFIG_COMPAT_BRK is not set
# CONFIG_SLAB is not set
CONFIG_SLUB=y
CONFIG_SLAB_MERGE_DEFAULT=y
# CONFIG_SLAB_FREELIST_RANDOM is not set
# CONFIG_SLAB_FREELIST_HARDENED is not set
# CONFIG_SHUFFLE_PAGE_ALLOCATOR is not set
CONFIG_SLUB_CPU_PARTIAL=y
CONFIG_SYSTEM_DATA_VERIFICATION=y
CONFIG_PROFILING=y
CONFIG_TRACEPOINTS=y

# end of General setup

CONFIG_ARM64=y
CONFIG_64BIT=y
CONFIG_MMU=y
CONFIG_ARM64_PAGE_SHIFT=12
CONFIG_ARM64_CONT_PTE_SHIFT=4
CONFIG_ARM64_CONT_PMD_SHIFT=4
CONFIG_ARCH_MMAP_RND_BITS_MIN=18
CONFIG_ARCH_MMAP_RND_BITS_MAX=33
CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MIN=11
CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX=16
CONFIG_STACKTRACE_SUPPORT=y
CONFIG_ILLEGAL_POINTER_VALUE=0xdead000000000000
CONFIG_LOCKDEP_SUPPORT=y
CONFIG_TRACE_IRQFLAGS_SUPPORT=y
CONFIG_GENERIC_BUG=y
CONFIG_GENERIC_BUG_RELATIVE_POINTERS=y
CONFIG_GENERIC_HWEIGHT=y
CONFIG_GENERIC_CSUM=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
CONFIG_ZONE_DMA=y
CONFIG_ZONE_DMA32=y
CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG=y
CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE=y
CONFIG_SMP=y
CONFIG_KERNEL_MODE_NEON=y
CONFIG_FIX_EARLYCON_MEM=y
CONFIG_PGTABLE_LEVELS=4
CONFIG_ARCH_SUPPORTS_UPROBES=y
CONFIG_ARCH_PROC_KCORE_TEXT=y

#
# Platform selection
#
CONFIG_ARCH_ACTIONS=y
CONFIG_ARCH_AGILEX=y
CONFIG_ARCH_SUNXI=y
CONFIG_ARCH_ALPINE=y
CONFIG_ARCH_BCM2835=y
CONFIG_ARCH_BCM_IPROC=y
CONFIG_ARCH_BERLIN=y
# CONFIG_ARCH_BITMAIN is not set
CONFIG_ARCH_BRCMSTB=y
CONFIG_ARCH_EXYNOS=y
# CONFIG_ARCH_SPARX5 is not set
CONFIG_ARCH_K3=y
CONFIG_ARCH_LAYERSCAPE=y
CONFIG_ARCH_LG1K=y
CONFIG_ARCH_HISI=y
# CONFIG_ARCH_KEEMBAY is not set
CONFIG_ARCH_MEDIATEK=y
CONFIG_ARCH_MESON=y
CONFIG_ARCH_MVEBU=y
CONFIG_ARCH_MXC=y
CONFIG_ARCH_QCOM=y
# CONFIG_ARCH_REALTEK is not set
CONFIG_ARCH_RENESAS=y
CONFIG_ARCH_ROCKCHIP=y
CONFIG_ARCH_S32=y
CONFIG_ARCH_SEATTLE=y
CONFIG_ARCH_STRATIX10=y
CONFIG_ARCH_SYNQUACER=y
CONFIG_ARCH_TEGRA=y
CONFIG_ARCH_SPRD=y
CONFIG_ARCH_THUNDER=y
CONFIG_ARCH_THUNDER2=y
CONFIG_ARCH_UNIPHIER=y
CONFIG_ARCH_VEXPRESS=y
# CONFIG_ARCH_VISCONTI is not set
CONFIG_ARCH_XGENE=y
CONFIG_ARCH_ZX=y
CONFIG_ARCH_ZYNQMP=y

# end of Platform selection

#
# Kernel Features
#

#
# ARM errata workarounds via the alternatives framework #
CONFIG_ARM64_WORKAROUND_CLEAN_CACHE=y CONFIG_ARM64_ERRATUM_826319=y CONFIG_ARM64_ERRATUM_827319=y CONFIG_ARM64_ERRATUM_824069=y CONFIG_ARM64_ERRATUM_819472=y CONFIG_ARM64_ERRATUM_832075=y CONFIG_ARM64_ERRATUM_834220=y CONFIG_ARM64_ERRATUM_845719=y CONFIG_ARM64_ERRATUM_843419=y CONFIG_ARM64_ERRATUM_1024718=y CONFIG_ARM64_ERRATUM_1418040=y CONFIG_ARM64_WORKAROUND_SPECULATIVE_AT=y CONFIG_ARM64_ERRATUM_1165522=y CONFIG_ARM64_ERRATUM_1319367=y CONFIG_ARM64_ERRATUM_1530923=y CONFIG_ARM64_WORKAROUND_REPEAT_TLBI=y CONFIG_ARM64_ERRATUM_1286807=y CONFIG_ARM64_ERRATUM_1463225=y CONFIG_ARM64_ERRATUM_1542419=y CONFIG_ARM64_ERRATUM_1508412=y CONFIG_CAVIUM_ERRATUM_22375=y CONFIG_CAVIUM_ERRATUM_23144=y CONFIG_CAVIUM_ERRATUM_23154=y CONFIG_CAVIUM_ERRATUM_27456=y CONFIG_CAVIUM_ERRATUM_30115=y CONFIG_CAVIUM_TX2_ERRATUM_219=y CONFIG_FUJITSU_ERRATUM_010001=y CONFIG_HISILICON_ERRATUM_161600802=y CONFIG_QCOM_FALKOR_ERRATUM_1003=y CONFIG_QCOM_FALKOR_ERRATUM_1009=y CONFIG_QCOM_QDF2400_ERRATUM_0065=y CONFIG_QCOM_FALKOR_ERRATUM_E1041=y CONFIG_SOCIONEXT_SYNQUACER_PREITS=y

# end of ARM errata workarounds via the alternatives framework

CONFIG_ARM64_4K_PAGES=y
# CONFIG_ARM64_16K_PAGES is not set
# CONFIG_ARM64_64K_PAGES is not set
# CONFIG_ARM64_VA_BITS_39 is not set
CONFIG_ARM64_VA_BITS_48=y
CONFIG_ARM64_VA_BITS=48
CONFIG_ARM64_PA_BITS_48=y
CONFIG_ARM64_PA_BITS=48
# CONFIG_CPU_BIG_ENDIAN is not set
CONFIG_CPU_LITTLE_ENDIAN=y
CONFIG_SCHED_MC=y
CONFIG_SCHED_SMT=y
CONFIG_NR_CPUS=256
CONFIG_HOTPLUG_CPU=y
CONFIG_NUMA=y
CONFIG_NODES_SHIFT=2
CONFIG_USE_PERCPU_NUMA_NODE_ID=y
CONFIG_HAVE_SETUP_PER_CPU_AREA=y
CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK=y
CONFIG_HOLES_IN_ZONE=y
# CONFIG_HZ_100 is not set
CONFIG_HZ_250=y
# CONFIG_HZ_300 is not set
# CONFIG_HZ_1000 is not set
CONFIG_HZ=250
CONFIG_SCHED_HRTICK=y
CONFIG_ARCH_SPARSEMEM_ENABLE=y
CONFIG_ARCH_SPARSEMEM_DEFAULT=y
CONFIG_ARCH_SELECT_MEMORY_MODEL=y
CONFIG_HW_PERF_EVENTS=y
CONFIG_SYS_SUPPORTS_HUGETLBFS=y
CONFIG_ARCH_WANT_HUGE_PMD_SHARE=y
CONFIG_ARCH_HAS_CACHE_LINE_SIZE=y
CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK=y
CONFIG_PARAVIRT=y
# CONFIG_PARAVIRT_TIME_ACCOUNTING is not set
CONFIG_KEXEC=y
# CONFIG_KEXEC_FILE is not set
CONFIG_CRASH_DUMP=y
CONFIG_XEN_DOM0=y
CONFIG_XEN=y
CONFIG_FORCE_MAX_ZONEORDER=11
CONFIG_UNMAP_KERNEL_AT_EL0=y
CONFIG_RODATA_FULL_DEFAULT_ENABLED=y
# CONFIG_ARM64_SW_TTBR0_PAN is not set
CONFIG_ARM64_TAGGED_ADDR_ABI=y
CONFIG_COMPAT=y
CONFIG_KUSER_HELPERS=y
# CONFIG_ARMV8_DEPRECATED is not set

#
# ARMv8.1 architectural features
#
CONFIG_ARM64_HW_AFDBM=y
CONFIG_ARM64_PAN=y
CONFIG_ARM64_LSE_ATOMICS=y
CONFIG_ARM64_USE_LSE_ATOMICS=y
CONFIG_ARM64_VHE=y

# end of ARMv8.1 architectural features

#
# ARMv8.2 architectural features
#
CONFIG_ARM64_UAO=y
# CONFIG_ARM64_PMEM is not set
CONFIG_ARM64_RAS_EXTN=y
CONFIG_ARM64_CNP=y

# end of ARMv8.2 architectural features

#
# ARMv8.3 architectural features
#
CONFIG_CC_HAS_SIGN_RETURN_ADDRESS=y
CONFIG_AS_HAS_PAC=y

# end of ARMv8.3 architectural features

#
# ARMv8.4 architectural features
#
CONFIG_ARM64_AMU_EXTN=y

# end of ARMv8.4 architectural features

#
# ARMv8.5 architectural features
#
CONFIG_ARM64_BTI=y
CONFIG_ARM64_E0PD=y
CONFIG_ARCH_RANDOM=y

# end of ARMv8.5 architectural features

CONFIG_ARM64_SVE=y
CONFIG_ARM64_MODULE_PLTS=y
# CONFIG_ARM64_PSEUDO_NMI is not set
CONFIG_RELOCATABLE=y
CONFIG_RANDOMIZE_BASE=y
CONFIG_RANDOMIZE_MODULE_REGION_FULL=y

# end of Kernel Features

#
# Boot options
#
# CONFIG_ARM64_ACPI_PARKING_PROTOCOL is not set
CONFIG_CMDLINE=""
CONFIG_EFI_STUB=y
CONFIG_EFI=y
CONFIG_DMI=y

# end of Boot options

CONFIG_SYSVIPC_COMPAT=y
CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION=y
CONFIG_ARCH_ENABLE_THP_MIGRATION=y

#
# Power management options
#
CONFIG_SUSPEND=y
CONFIG_SUSPEND_FREEZER=y
CONFIG_HIBERNATE_CALLBACKS=y
CONFIG_HIBERNATION=y
CONFIG_HIBERNATION_SNAPSHOT_DEV=y
CONFIG_PM_STD_PARTITION=""
CONFIG_PM_SLEEP=y
CONFIG_PM_SLEEP_SMP=y
# CONFIG_PM_AUTOSLEEP is not set
# CONFIG_PM_WAKELOCKS is not set
CONFIG_PM=y
# CONFIG_PM_DEBUG is not set
CONFIG_PM_CLK=y
CONFIG_PM_GENERIC_DOMAINS=y
CONFIG_WQ_POWER_EFFICIENT_DEFAULT=y
CONFIG_PM_GENERIC_DOMAINS_SLEEP=y
CONFIG_PM_GENERIC_DOMAINS_OF=y
CONFIG_CPU_PM=y
CONFIG_ENERGY_MODEL=y
CONFIG_ARCH_HIBERNATION_POSSIBLE=y
CONFIG_ARCH_HIBERNATION_HEADER=y
CONFIG_ARCH_SUSPEND_POSSIBLE=y

# end of Power management options

#
# CPU Power Management
#

#
# CPU Idle
#
CONFIG_CPU_IDLE=y
CONFIG_CPU_IDLE_MULTIPLE_DRIVERS=y
# CONFIG_CPU_IDLE_GOV_LADDER is not set
CONFIG_CPU_IDLE_GOV_MENU=y
# CONFIG_CPU_IDLE_GOV_TEO is not set
CONFIG_DT_IDLE_STATES=y

#
# ARM CPU Idle Drivers
#
CONFIG_ARM_CPUIDLE=y
CONFIG_ARM_PSCI_CPUIDLE=y
CONFIG_ARM_PSCI_CPUIDLE_DOMAIN=y

# end of ARM CPU Idle Drivers
# end of CPU Idle

#
# CPU Frequency scaling
#
CONFIG_CPU_FREQ=y CONFIG_CPU_FREQ_GOV_ATTR_SET=y CONFIG_CPU_FREQ_GOV_COMMON=y CONFIG_CPU_FREQ_STAT=y CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE=y
# CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE is not set # CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE is not set # CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND is not set # CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE is not set # CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL is not set CONFIG_CPU_FREQ_GOV_PERFORMANCE=y CONFIG_CPU_FREQ_GOV_POWERSAVE=m CONFIG_CPU_FREQ_GOV_USERSPACE=y CONFIG_CPU_FREQ_GOV_ONDEMAND=y CONFIG_CPU_FREQ_GOV_CONSERVATIVE=m CONFIG_CPU_FREQ_GOV_SCHEDUTIL=y

#
# CPU frequency scaling drivers
#
CONFIG_CPUFREQ_DT=y
CONFIG_CPUFREQ_DT_PLATDEV=y
CONFIG_ACPI_CPPC_CPUFREQ=m
CONFIG_ARM_ALLWINNER_SUN50I_CPUFREQ_NVMEM=m
CONFIG_ARM_ARMADA_37XX_CPUFREQ=y
# CONFIG_ARM_ARMADA_8K_CPUFREQ is not set
CONFIG_ARM_SCPI_CPUFREQ=y
CONFIG_ARM_BRCMSTB_AVS_CPUFREQ=y
CONFIG_ARM_IMX_CPUFREQ_DT=m
# CONFIG_ARM_MEDIATEK_CPUFREQ is not set
CONFIG_ARM_QCOM_CPUFREQ_NVMEM=y
CONFIG_ARM_QCOM_CPUFREQ_HW=y
CONFIG_ARM_RASPBERRYPI_CPUFREQ=m
CONFIG_ARM_TEGRA20_CPUFREQ=y
CONFIG_ARM_TEGRA124_CPUFREQ=y
CONFIG_ARM_TEGRA186_CPUFREQ=y
CONFIG_ARM_TEGRA194_CPUFREQ=y
CONFIG_QORIQ_CPUFREQ=y

# end of CPU Frequency scaling
# end of CPU Power Management

#
# Firmware Drivers
#
# CONFIG_ARM_SCMI_PROTOCOL is not set CONFIG_ARM_SCPI_PROTOCOL=y CONFIG_ARM_SCPI_POWER_DOMAIN=y
# CONFIG_ARM_SDE_INTERFACE is not set CONFIG_DMIID=y
# CONFIG_DMI_SYSFS is not set
# CONFIG_ISCSI_IBFT is not set CONFIG_RASPBERRYPI_FIRMWARE=y
# CONFIG_FW_CFG_SYSFS is not set CONFIG_INTEL_STRATIX10_SERVICE=y CONFIG_INTEL_STRATIX10_RSU=m CONFIG_QCOM_SCM=y
# CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT is not set CONFIG_TI_SCI_PROTOCOL=y
# CONFIG_TURRIS_MOX_RWTM is not set CONFIG_TEE_BNXT_FW=y
# CONFIG_GOOGLE_FIRMWARE is not set

#
# EFI (Extensible Firmware Interface) Support #
CONFIG_EFI_ESRT=y
CONFIG_EFI_VARS_PSTORE=y
# CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE is not set CONFIG_EFI_PARAMS_FROM_FDT=y CONFIG_EFI_RUNTIME_WRAPPERS=y CONFIG_EFI_GENERIC_STUB=y CONFIG_EFI_ARMSTUB_DTB_LOADER=y CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER=y # CONFIG_EFI_BOOTLOADER_CONTROL is not set CONFIG_EFI_CAPSULE_LOADER=y
# CONFIG_EFI_TEST is not set
# CONFIG_RESET_ATTACK_MITIGATION is not set # CONFIG_EFI_DISABLE_PCI_DMA is not set

# end of EFI (Extensible Firmware Interface) Support

CONFIG_UEFI_CPER=y
CONFIG_UEFI_CPER_ARM=y
CONFIG_EFI_EARLYCON=y
CONFIG_EFI_CUSTOM_SSDT_OVERLAYS=y
# CONFIG_IMX_DSP is not set
CONFIG_IMX_SCU=y
CONFIG_IMX_SCU_PD=y
CONFIG_MESON_SM=y
CONFIG_ARM_PSCI_FW=y
# CONFIG_ARM_PSCI_CHECKER is not set
CONFIG_HAVE_ARM_SMCCC=y
CONFIG_HAVE_ARM_SMCCC_DISCOVERY=y
CONFIG_ARM_SMCCC_SOC_ID=y

#
# Tegra firmware driver
#
CONFIG_TEGRA_IVC=y
CONFIG_TEGRA_BPMP=y

# end of Tegra firmware driver

#
# Zynq MPSoC Firmware Drivers
#
CONFIG_ZYNQMP_FIRMWARE=y
# CONFIG_ZYNQMP_FIRMWARE_DEBUG is not set

# end of Zynq MPSoC Firmware Drivers
# end of Firmware Drivers

CONFIG_ARCH_SUPPORTS_ACPI=y
CONFIG_ACPI=y
CONFIG_ACPI_GENERIC_GSI=y
CONFIG_ACPI_CCA_REQUIRED=y
# CONFIG_ACPI_DEBUGGER is not set
CONFIG_ACPI_SPCR_TABLE=y
# CONFIG_ACPI_EC_DEBUGFS is not set
CONFIG_ACPI_AC=y
CONFIG_ACPI_BATTERY=y
CONFIG_ACPI_BUTTON=y
CONFIG_ACPI_FAN=y
# CONFIG_ACPI_TAD is not set
# CONFIG_ACPI_DOCK is not set
CONFIG_ACPI_PROCESSOR_IDLE=y
CONFIG_ACPI_MCFG=y
CONFIG_ACPI_CPPC_LIB=y
CONFIG_ACPI_PROCESSOR=y
# CONFIG_ACPI_IPMI is not set
CONFIG_ACPI_HOTPLUG_CPU=y
CONFIG_ACPI_THERMAL=y
CONFIG_ARCH_HAS_ACPI_TABLE_UPGRADE=y
CONFIG_ACPI_TABLE_UPGRADE=y
# CONFIG_ACPI_DEBUG is not set
# CONFIG_ACPI_PCI_SLOT is not set
CONFIG_ACPI_CONTAINER=y
CONFIG_ACPI_HED=y
# CONFIG_ACPI_CUSTOM_METHOD is not set
# CONFIG_ACPI_BGRT is not set
CONFIG_ACPI_REDUCED_HARDWARE_ONLY=y
CONFIG_ACPI_NUMA=y
# CONFIG_ACPI_HMAT is not set
CONFIG_HAVE_ACPI_APEI=y
CONFIG_ACPI_APEI=y
CONFIG_ACPI_APEI_GHES=y
CONFIG_ACPI_APEI_SEA=y
CONFIG_ACPI_APEI_MEMORY_FAILURE=y
CONFIG_ACPI_APEI_EINJ=y
# CONFIG_ACPI_APEI_ERST_DEBUG is not set
# CONFIG_ACPI_CONFIGFS is not set
CONFIG_ACPI_IORT=y
CONFIG_ACPI_GTDT=y
CONFIG_ACPI_PPTT=y
# CONFIG_PMIC_OPREGION is not set
CONFIG_IRQ_BYPASS_MANAGER=y
CONFIG_VIRTUALIZATION=y
CONFIG_KVM=y
CONFIG_HAVE_KVM_IRQCHIP=y
CONFIG_HAVE_KVM_IRQFD=y
CONFIG_HAVE_KVM_IRQ_ROUTING=y
CONFIG_HAVE_KVM_EVENTFD=y
CONFIG_KVM_MMIO=y
CONFIG_HAVE_KVM_MSI=y
CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT=y
CONFIG_KVM_VFIO=y
CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL=y
CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT=y
CONFIG_HAVE_KVM_IRQ_BYPASS=y
CONFIG_HAVE_KVM_VCPU_RUN_PID_CHANGE=y
CONFIG_KVM_ARM_PMU=y
CONFIG_ARM64_CRYPTO=y
CONFIG_CRYPTO_SHA256_ARM64=y
CONFIG_CRYPTO_SHA512_ARM64=m
CONFIG_CRYPTO_SHA1_ARM64_CE=y
CONFIG_CRYPTO_SHA2_ARM64_CE=y
CONFIG_CRYPTO_SHA512_ARM64_CE=m
CONFIG_CRYPTO_SHA3_ARM64=m
CONFIG_CRYPTO_SM3_ARM64_CE=m
# CONFIG_CRYPTO_SM4_ARM64_CE is not set
CONFIG_CRYPTO_GHASH_ARM64_CE=y
CONFIG_CRYPTO_CRCT10DIF_ARM64_CE=m
CONFIG_CRYPTO_AES_ARM64=y
CONFIG_CRYPTO_AES_ARM64_CE=y
CONFIG_CRYPTO_AES_ARM64_CE_CCM=y
CONFIG_CRYPTO_AES_ARM64_CE_BLK=y
CONFIG_CRYPTO_AES_ARM64_NEON_BLK=m
CONFIG_CRYPTO_CHACHA20_NEON=m
# CONFIG_CRYPTO_POLY1305_NEON is not set
# CONFIG_CRYPTO_NHPOLY1305_NEON is not set
CONFIG_CRYPTO_AES_ARM64_BS=m

#
# General architecture-dependent options
#
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_SET_FS=y
# CONFIG_KPROBES is not set
CONFIG_JUMP_LABEL=y
# CONFIG_STATIC_KEYS_SELFTEST is not set
CONFIG_UPROBES=y
CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y
CONFIG_HAVE_KPROBES=y
CONFIG_HAVE_KRETPROBES=y
CONFIG_HAVE_FUNCTION_ERROR_INJECTION=y
CONFIG_HAVE_NMI=y
CONFIG_HAVE_ARCH_TRACEHOOK=y
CONFIG_HAVE_DMA_CONTIGUOUS=y
CONFIG_GENERIC_SMP_IDLE_THREAD=y
CONFIG_GENERIC_IDLE_POLL_SETUP=y
CONFIG_ARCH_HAS_FORTIFY_SOURCE=y
CONFIG_ARCH_HAS_KEEPINITRD=y
CONFIG_ARCH_HAS_SET_MEMORY=y
CONFIG_ARCH_HAS_SET_DIRECT_MAP=y
CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST=y
CONFIG_HAVE_ASM_MODVERSIONS=y
CONFIG_HAVE_REGS_AND_STACK_ACCESS_API=y
CONFIG_HAVE_RSEQ=y
CONFIG_HAVE_FUNCTION_ARG_ACCESS_API=y
CONFIG_HAVE_HW_BREAKPOINT=y
CONFIG_HAVE_PERF_REGS=y
CONFIG_HAVE_PERF_USER_STACK_DUMP=y
CONFIG_HAVE_ARCH_JUMP_LABEL=y
CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE=y
CONFIG_MMU_GATHER_TABLE_FREE=y
CONFIG_MMU_GATHER_RCU_TABLE_FREE=y
CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG=y
CONFIG_HAVE_ALIGNED_STRUCT_PAGE=y
CONFIG_HAVE_CMPXCHG_LOCAL=y
CONFIG_HAVE_CMPXCHG_DOUBLE=y
CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION=y
CONFIG_HAVE_ARCH_SECCOMP=y
CONFIG_HAVE_ARCH_SECCOMP_FILTER=y
CONFIG_SECCOMP=y
CONFIG_SECCOMP_FILTER=y
CONFIG_HAVE_ARCH_STACKLEAK=y
CONFIG_HAVE_STACKPROTECTOR=y
CONFIG_STACKPROTECTOR=y
CONFIG_STACKPROTECTOR_STRONG=y
CONFIG_HAVE_CONTEXT_TRACKING=y
CONFIG_HAVE_VIRT_CPU_ACCOUNTING_GEN=y
CONFIG_HAVE_IRQ_TIME_ACCOUNTING=y
CONFIG_HAVE_MOVE_PUD=y
CONFIG_HAVE_MOVE_PMD=y
CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE=y
CONFIG_HAVE_ARCH_HUGE_VMAP=y
CONFIG_HAVE_MOD_ARCH_SPECIFIC=y
CONFIG_MODULES_USE_ELF_RELA=y
CONFIG_ARCH_HAS_ELF_RANDOMIZE=y
CONFIG_HAVE_ARCH_MMAP_RND_BITS=y
CONFIG_ARCH_MMAP_RND_BITS=18
CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS=y
CONFIG_ARCH_MMAP_RND_COMPAT_BITS=11
CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT=y
CONFIG_CLONE_BACKWARDS=y
CONFIG_OLD_SIGSUSPEND3=y
CONFIG_COMPAT_OLD_SIGACTION=y
CONFIG_COMPAT_32BIT_TIME=y
CONFIG_HAVE_ARCH_VMAP_STACK=y
CONFIG_VMAP_STACK=y
CONFIG_ARCH_HAS_STRICT_KERNEL_RWX=y
CONFIG_STRICT_KERNEL_RWX=y
CONFIG_ARCH_HAS_STRICT_MODULE_RWX=y
CONFIG_STRICT_MODULE_RWX=y
CONFIG_HAVE_ARCH_COMPILER_H=y
CONFIG_HAVE_ARCH_PREL32_RELOCATIONS=y
CONFIG_ARCH_USE_MEMREMAP_PROT=y
# CONFIG_LOCK_EVENT_COUNTS is not set
CONFIG_ARCH_HAS_RELR=y
CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC=y
CONFIG_HAVE_ARCH_PFN_VALID=y

#
# GCOV-based kernel profiling
#
# CONFIG_GCOV_KERNEL is not set
CONFIG_ARCH_HAS_GCOV_PROFILE_ALL=y

# end of GCOV-based kernel profiling

CONFIG_HAVE_GCC_PLUGINS=y
CONFIG_GCC_PLUGINS=y
# CONFIG_GCC_PLUGIN_LATENT_ENTROPY is not set
# CONFIG_GCC_PLUGIN_RANDSTRUCT is not set

# end of General architecture-dependent options

CONFIG_RT_MUTEXES=y
CONFIG_BASE_SMALL=0
CONFIG_MODULES=y
# CONFIG_MODULE_FORCE_LOAD is not set CONFIG_MODULE_UNLOAD=y
# CONFIG_MODULE_FORCE_UNLOAD is not set
# CONFIG_MODVERSIONS is not set
# CONFIG_MODULE_SRCVERSION_ALL is not set
# CONFIG_MODULE_SIG is not set
# CONFIG_MODULE_COMPRESS is not set
# CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS is not set # CONFIG_UNUSED_SYMBOLS is not set
# CONFIG_TRIM_UNUSED_KSYMS is not set CONFIG_MODULES_TREE_LOOKUP=y
CONFIG_BLOCK=y
CONFIG_BLK_SCSI_REQUEST=y
CONFIG_BLK_DEV_BSG=y
CONFIG_BLK_DEV_BSGLIB=y CONFIG_BLK_DEV_INTEGRITY=y CONFIG_BLK_DEV_INTEGRITY_T10=y
# CONFIG_BLK_DEV_ZONED is not set
# CONFIG_BLK_DEV_THROTTLING is not set
# CONFIG_BLK_CMDLINE_PARSER is not set
# CONFIG_BLK_WBT is not set
# CONFIG_BLK_CGROUP_IOLATENCY is not set
# CONFIG_BLK_CGROUP_IOCOST is not set CONFIG_BLK_DEBUG_FS=y
# CONFIG_BLK_SED_OPAL is not set
# CONFIG_BLK_INLINE_ENCRYPTION is not set

#
# Partition Types
#
# CONFIG_PARTITION_ADVANCED is not set
CONFIG_MSDOS_PARTITION=y
CONFIG_EFI_PARTITION=y

# end of Partition Types

CONFIG_BLOCK_COMPAT=y
CONFIG_BLK_MQ_PCI=y
CONFIG_BLK_MQ_VIRTIO=y
CONFIG_BLK_PM=y

#
# IO Schedulers
#
CONFIG_MQ_IOSCHED_DEADLINE=y
CONFIG_MQ_IOSCHED_KYBER=y
# CONFIG_IOSCHED_BFQ is not set

# end of IO Schedulers

CONFIG_PREEMPT_NOTIFIERS=y
CONFIG_ASN1=y
CONFIG_UNINLINE_SPIN_UNLOCK=y
CONFIG_ARCH_SUPPORTS_ATOMIC_RMW=y
CONFIG_MUTEX_SPIN_ON_OWNER=y
CONFIG_RWSEM_SPIN_ON_OWNER=y
CONFIG_LOCK_SPIN_ON_OWNER=y
CONFIG_ARCH_USE_QUEUED_SPINLOCKS=y
CONFIG_QUEUED_SPINLOCKS=y
CONFIG_ARCH_USE_QUEUED_RWLOCKS=y
CONFIG_QUEUED_RWLOCKS=y
CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE=y
CONFIG_ARCH_HAS_SYSCALL_WRAPPER=y
CONFIG_FREEZER=y

#
# Executable file formats
#
CONFIG_BINFMT_ELF=y
CONFIG_COMPAT_BINFMT_ELF=y
CONFIG_ARCH_BINFMT_ELF_STATE=y
CONFIG_ARCH_HAVE_ELF_PROT=y
CONFIG_ARCH_USE_GNU_PROPERTY=y
CONFIG_ELFCORE=y
# CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
CONFIG_BINFMT_SCRIPT=y
# CONFIG_BINFMT_MISC is not set
CONFIG_COREDUMP=y

# end of Executable file formats

#
# Memory Management options
#
CONFIG_SELECT_MEMORY_MODEL=y
CONFIG_SPARSEMEM_MANUAL=y
CONFIG_SPARSEMEM=y
CONFIG_NEED_MULTIPLE_NODES=y
CONFIG_SPARSEMEM_EXTREME=y
CONFIG_SPARSEMEM_VMEMMAP_ENABLE=y
CONFIG_SPARSEMEM_VMEMMAP=y
CONFIG_HAVE_FAST_GUP=y
CONFIG_ARCH_KEEP_MEMBLOCK=y
CONFIG_MEMORY_ISOLATION=y
# CONFIG_MEMORY_HOTPLUG is not set
CONFIG_SPLIT_PTLOCK_CPUS=4
CONFIG_MEMORY_BALLOON=y
CONFIG_BALLOON_COMPACTION=y
CONFIG_COMPACTION=y
CONFIG_PAGE_REPORTING=y
CONFIG_MIGRATION=y
CONFIG_CONTIG_ALLOC=y
CONFIG_PHYS_ADDR_T_64BIT=y
CONFIG_BOUNCE=y
CONFIG_MMU_NOTIFIER=y
CONFIG_KSM=y
CONFIG_DEFAULT_MMAP_MIN_ADDR=4096
CONFIG_ARCH_SUPPORTS_MEMORY_FAILURE=y
CONFIG_MEMORY_FAILURE=y
# CONFIG_HWPOISON_INJECT is not set
CONFIG_TRANSPARENT_HUGEPAGE=y
CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS=y
# CONFIG_TRANSPARENT_HUGEPAGE_MADVISE is not set
# CONFIG_CLEANCACHE is not set
# CONFIG_FRONTSWAP is not set
CONFIG_CMA=y
# CONFIG_CMA_DEBUG is not set
# CONFIG_CMA_DEBUGFS is not set
CONFIG_CMA_AREAS=7
# CONFIG_ZPOOL is not set
# CONFIG_ZBUD is not set
# CONFIG_ZSMALLOC is not set
CONFIG_GENERIC_EARLY_IOREMAP=y
# CONFIG_DEFERRED_STRUCT_PAGE_INIT is not set
# CONFIG_IDLE_PAGE_TRACKING is not set
CONFIG_ARCH_HAS_PTE_DEVMAP=y
CONFIG_FRAME_VECTOR=y
# CONFIG_PERCPU_STATS is not set
# CONFIG_GUP_TEST is not set
# CONFIG_READ_ONLY_THP_FOR_FS is not set
CONFIG_ARCH_HAS_PTE_SPECIAL=y

# end of Memory Management options

CONFIG_NET=y
CONFIG_NET_INGRESS=y
CONFIG_SKB_EXTENSIONS=y

#
# Networking options
#
CONFIG_PACKET=y
# CONFIG_PACKET_DIAG is not set
CONFIG_UNIX=y
CONFIG_UNIX_SCM=y
# CONFIG_UNIX_DIAG is not set
# CONFIG_TLS is not set
# CONFIG_XFRM_USER is not set
# CONFIG_NET_KEY is not set
CONFIG_INET=y
CONFIG_IP_MULTICAST=y
# CONFIG_IP_ADVANCED_ROUTER is not set
CONFIG_IP_PNP=y
CONFIG_IP_PNP_DHCP=y
CONFIG_IP_PNP_BOOTP=y
# CONFIG_IP_PNP_RARP is not set
# CONFIG_NET_IPIP is not set
# CONFIG_NET_IPGRE_DEMUX is not set
CONFIG_NET_IP_TUNNEL=m
# CONFIG_IP_MROUTE is not set
# CONFIG_SYN_COOKIES is not set
# CONFIG_NET_IPVTI is not set
# CONFIG_NET_FOU is not set
# CONFIG_NET_FOU_IP_TUNNELS is not set
# CONFIG_INET_AH is not set
# CONFIG_INET_ESP is not set
# CONFIG_INET_IPCOMP is not set
CONFIG_INET_TUNNEL=m
CONFIG_INET_DIAG=y
CONFIG_INET_TCP_DIAG=y
# CONFIG_INET_UDP_DIAG is not set
# CONFIG_INET_RAW_DIAG is not set
# CONFIG_INET_DIAG_DESTROY is not set
# CONFIG_TCP_CONG_ADVANCED is not set
CONFIG_TCP_CONG_CUBIC=y
CONFIG_DEFAULT_TCP_CONG="cubic"
# CONFIG_TCP_MD5SIG is not set
CONFIG_IPV6=m
# CONFIG_IPV6_ROUTER_PREF is not set
# CONFIG_IPV6_OPTIMISTIC_DAD is not set
# CONFIG_INET6_AH is not set
# CONFIG_INET6_ESP is not set
# CONFIG_INET6_IPCOMP is not set
# CONFIG_IPV6_MIP6 is not set
# CONFIG_IPV6_ILA is not set
# CONFIG_IPV6_VTI is not set
CONFIG_IPV6_SIT=m
# CONFIG_IPV6_SIT_6RD is not set
CONFIG_IPV6_NDISC_NODETYPE=y
# CONFIG_IPV6_TUNNEL is not set
# CONFIG_IPV6_MULTIPLE_TABLES is not set
# CONFIG_IPV6_MROUTE is not set
# CONFIG_IPV6_SEG6_LWTUNNEL is not set
# CONFIG_IPV6_SEG6_HMAC is not set
# CONFIG_IPV6_RPL_LWTUNNEL is not set
# CONFIG_NETLABEL is not set
# CONFIG_MPTCP is not set
# CONFIG_NETWORK_SECMARK is not set
CONFIG_NET_PTP_CLASSIFY=y
# CONFIG_NETWORK_PHY_TIMESTAMPING is not set
CONFIG_NETFILTER=y
CONFIG_NETFILTER_ADVANCED=y
# CONFIG_BRIDGE_NETFILTER is not set

#
# Core Netfilter Configuration
#
CONFIG_NETFILTER_INGRESS=y
CONFIG_NETFILTER_NETLINK=m
# CONFIG_NETFILTER_NETLINK_ACCT is not set
# CONFIG_NETFILTER_NETLINK_QUEUE is not set
# CONFIG_NETFILTER_NETLINK_LOG is not set
# CONFIG_NETFILTER_NETLINK_OSF is not set
CONFIG_NF_CONNTRACK=m
CONFIG_NF_LOG_COMMON=m
# CONFIG_NF_LOG_NETDEV is not set
# CONFIG_NF_CONNTRACK_MARK is not set
# CONFIG_NF_CONNTRACK_ZONES is not set
CONFIG_NF_CONNTRACK_PROCFS=y
CONFIG_NF_CONNTRACK_EVENTS=y
CONFIG_NF_CONNTRACK_TIMEOUT=y
# CONFIG_NF_CONNTRACK_TIMESTAMP is not set
# CONFIG_NF_CONNTRACK_LABELS is not set
CONFIG_NF_CT_PROTO_DCCP=y
CONFIG_NF_CT_PROTO_SCTP=y
CONFIG_NF_CT_PROTO_UDPLITE=y
# CONFIG_NF_CONNTRACK_AMANDA is not set
# CONFIG_NF_CONNTRACK_FTP is not set
# CONFIG_NF_CONNTRACK_H323 is not set
# CONFIG_NF_CONNTRACK_IRC is not set
# CONFIG_NF_CONNTRACK_NETBIOS_NS is not set
# CONFIG_NF_CONNTRACK_SNMP is not set
# CONFIG_NF_CONNTRACK_PPTP is not set
# CONFIG_NF_CONNTRACK_SANE is not set
# CONFIG_NF_CONNTRACK_SIP is not set
# CONFIG_NF_CONNTRACK_TFTP is not set
# CONFIG_NF_CT_NETLINK is not set
CONFIG_NF_CT_NETLINK_TIMEOUT=m
CONFIG_NF_NAT=m
CONFIG_NF_NAT_MASQUERADE=y
# CONFIG_NF_TABLES is not set
CONFIG_NETFILTER_XTABLES=m

#
# Xtables combined modules
#
# CONFIG_NETFILTER_XT_MARK is not set
# CONFIG_NETFILTER_XT_CONNMARK is not set

#
# Xtables targets
#
# CONFIG_NETFILTER_XT_TARGET_AUDIT is not set CONFIG_NETFILTER_XT_TARGET_CHECKSUM=m
# CONFIG_NETFILTER_XT_TARGET_CLASSIFY is not set # CONFIG_NETFILTER_XT_TARGET_CONNMARK is not set # CONFIG_NETFILTER_XT_TARGET_DSCP is not set # CONFIG_NETFILTER_XT_TARGET_HL is not set # CONFIG_NETFILTER_XT_TARGET_HMARK is not set # CONFIG_NETFILTER_XT_TARGET_IDLETIMER is not set # CONFIG_NETFILTER_XT_TARGET_LED is not set CONFIG_NETFILTER_XT_TARGET_LOG=m
# CONFIG_NETFILTER_XT_TARGET_MARK is not set CONFIG_NETFILTER_XT_NAT=m
# CONFIG_NETFILTER_XT_TARGET_NETMAP is not set # CONFIG_NETFILTER_XT_TARGET_NFLOG is not set # CONFIG_NETFILTER_XT_TARGET_NFQUEUE is not set # CONFIG_NETFILTER_XT_TARGET_RATEEST is not set # CONFIG_NETFILTER_XT_TARGET_REDIRECT is not set CONFIG_NETFILTER_XT_TARGET_MASQUERADE=m
# CONFIG_NETFILTER_XT_TARGET_TEE is not set # CONFIG_NETFILTER_XT_TARGET_TPROXY is not set # CONFIG_NETFILTER_XT_TARGET_TCPMSS is not set # CONFIG_NETFILTER_XT_TARGET_TCPOPTSTRIP is not set

#
# Xtables matches
#
CONFIG_NETFILTER_XT_MATCH_ADDRTYPE=m
# CONFIG_NETFILTER_XT_MATCH_BPF is not set
# CONFIG_NETFILTER_XT_MATCH_CGROUP is not set
# CONFIG_NETFILTER_XT_MATCH_CLUSTER is not set
# CONFIG_NETFILTER_XT_MATCH_COMMENT is not set
# CONFIG_NETFILTER_XT_MATCH_CONNBYTES is not set
# CONFIG_NETFILTER_XT_MATCH_CONNLABEL is not set
# CONFIG_NETFILTER_XT_MATCH_CONNLIMIT is not set
# CONFIG_NETFILTER_XT_MATCH_CONNMARK is not set
CONFIG_NETFILTER_XT_MATCH_CONNTRACK=m
# CONFIG_NETFILTER_XT_MATCH_CPU is not set
# CONFIG_NETFILTER_XT_MATCH_DCCP is not set
# CONFIG_NETFILTER_XT_MATCH_DEVGROUP is not set
# CONFIG_NETFILTER_XT_MATCH_DSCP is not set
# CONFIG_NETFILTER_XT_MATCH_ECN is not set
# CONFIG_NETFILTER_XT_MATCH_ESP is not set
# CONFIG_NETFILTER_XT_MATCH_HASHLIMIT is not set
# CONFIG_NETFILTER_XT_MATCH_HELPER is not set
# CONFIG_NETFILTER_XT_MATCH_HL is not set
# CONFIG_NETFILTER_XT_MATCH_IPCOMP is not set
# CONFIG_NETFILTER_XT_MATCH_IPRANGE is not set
# CONFIG_NETFILTER_XT_MATCH_L2TP is not set
# CONFIG_NETFILTER_XT_MATCH_LENGTH is not set
# CONFIG_NETFILTER_XT_MATCH_LIMIT is not set
# CONFIG_NETFILTER_XT_MATCH_MAC is not set
# CONFIG_NETFILTER_XT_MATCH_MARK is not set
# CONFIG_NETFILTER_XT_MATCH_MULTIPORT is not set
# CONFIG_NETFILTER_XT_MATCH_NFACCT is not set
# CONFIG_NETFILTER_XT_MATCH_OSF is not set
# CONFIG_NETFILTER_XT_MATCH_OWNER is not set
# CONFIG_NETFILTER_XT_MATCH_PKTTYPE is not set
# CONFIG_NETFILTER_XT_MATCH_QUOTA is not set
# CONFIG_NETFILTER_XT_MATCH_RATEEST is not set
# CONFIG_NETFILTER_XT_MATCH_REALM is not set
# CONFIG_NETFILTER_XT_MATCH_RECENT is not set
# CONFIG_NETFILTER_XT_MATCH_SCTP is not set
# CONFIG_NETFILTER_XT_MATCH_SOCKET is not set
# CONFIG_NETFILTER_XT_MATCH_STATE is not set
# CONFIG_NETFILTER_XT_MATCH_STATISTIC is not set
# CONFIG_NETFILTER_XT_MATCH_STRING is not set
# CONFIG_NETFILTER_XT_MATCH_TCPMSS is not set
# CONFIG_NETFILTER_XT_MATCH_TIME is not set
# CONFIG_NETFILTER_XT_MATCH_U32 is not set

# end of Core Netfilter Configuration

# CONFIG_IP_SET is not set
# CONFIG_IP_VS is not set

#
# IP: Netfilter Configuration
#
CONFIG_NF_DEFRAG_IPV4=m
# CONFIG_NF_SOCKET_IPV4 is not set
# CONFIG_NF_TPROXY_IPV4 is not set
# CONFIG_NF_DUP_IPV4 is not set
# CONFIG_NF_LOG_ARP is not set
CONFIG_NF_LOG_IPV4=m
CONFIG_NF_REJECT_IPV4=m
CONFIG_IP_NF_IPTABLES=m
# CONFIG_IP_NF_MATCH_AH is not set
# CONFIG_IP_NF_MATCH_ECN is not set
# CONFIG_IP_NF_MATCH_RPFILTER is not set
# CONFIG_IP_NF_MATCH_TTL is not set
CONFIG_IP_NF_FILTER=m
CONFIG_IP_NF_TARGET_REJECT=m
# CONFIG_IP_NF_TARGET_SYNPROXY is not set
CONFIG_IP_NF_NAT=m
CONFIG_IP_NF_TARGET_MASQUERADE=m
# CONFIG_IP_NF_TARGET_NETMAP is not set
# CONFIG_IP_NF_TARGET_REDIRECT is not set
CONFIG_IP_NF_MANGLE=m
# CONFIG_IP_NF_TARGET_CLUSTERIP is not set
# CONFIG_IP_NF_TARGET_ECN is not set
# CONFIG_IP_NF_TARGET_TTL is not set
# CONFIG_IP_NF_RAW is not set
# CONFIG_IP_NF_SECURITY is not set
# CONFIG_IP_NF_ARPTABLES is not set

# end of IP: Netfilter Configuration

#
# IPv6: Netfilter Configuration
#
# CONFIG_NF_SOCKET_IPV6 is not set
# CONFIG_NF_TPROXY_IPV6 is not set
# CONFIG_NF_DUP_IPV6 is not set
CONFIG_NF_REJECT_IPV6=m
CONFIG_NF_LOG_IPV6=m
CONFIG_IP6_NF_IPTABLES=m
# CONFIG_IP6_NF_MATCH_AH is not set
# CONFIG_IP6_NF_MATCH_EUI64 is not set
# CONFIG_IP6_NF_MATCH_FRAG is not set
# CONFIG_IP6_NF_MATCH_OPTS is not set
# CONFIG_IP6_NF_MATCH_HL is not set
# CONFIG_IP6_NF_MATCH_IPV6HEADER is not set
# CONFIG_IP6_NF_MATCH_MH is not set
# CONFIG_IP6_NF_MATCH_RPFILTER is not set
# CONFIG_IP6_NF_MATCH_RT is not set
# CONFIG_IP6_NF_MATCH_SRH is not set
# CONFIG_IP6_NF_TARGET_HL is not set
CONFIG_IP6_NF_FILTER=m
CONFIG_IP6_NF_TARGET_REJECT=m
# CONFIG_IP6_NF_TARGET_SYNPROXY is not set
CONFIG_IP6_NF_MANGLE=m
# CONFIG_IP6_NF_RAW is not set
# CONFIG_IP6_NF_SECURITY is not set
CONFIG_IP6_NF_NAT=m
CONFIG_IP6_NF_TARGET_MASQUERADE=m
# CONFIG_IP6_NF_TARGET_NPT is not set

# end of IPv6: Netfilter Configuration

CONFIG_NF_DEFRAG_IPV6=m
# CONFIG_NF_CONNTRACK_BRIDGE is not set
# CONFIG_BRIDGE_NF_EBTABLES is not set
# CONFIG_BPFILTER is not set
# CONFIG_IP_DCCP is not set
# CONFIG_IP_SCTP is not set
# CONFIG_RDS is not set
# CONFIG_TIPC is not set
# CONFIG_ATM is not set
# CONFIG_L2TP is not set
CONFIG_STP=m
CONFIG_GARP=m
CONFIG_MRP=m
CONFIG_BRIDGE=m
CONFIG_BRIDGE_IGMP_SNOOPING=y
CONFIG_BRIDGE_VLAN_FILTERING=y
# CONFIG_BRIDGE_MRP is not set
# CONFIG_BRIDGE_CFM is not set
CONFIG_HAVE_NET_DSA=y
CONFIG_NET_DSA=m
# CONFIG_NET_DSA_TAG_AR9331 is not set
# CONFIG_NET_DSA_TAG_BRCM is not set
# CONFIG_NET_DSA_TAG_BRCM_PREPEND is not set
# CONFIG_NET_DSA_TAG_HELLCREEK is not set
# CONFIG_NET_DSA_TAG_GSWIP is not set
# CONFIG_NET_DSA_TAG_DSA is not set
# CONFIG_NET_DSA_TAG_EDSA is not set
# CONFIG_NET_DSA_TAG_MTK is not set
# CONFIG_NET_DSA_TAG_KSZ is not set
# CONFIG_NET_DSA_TAG_RTL4_A is not set
CONFIG_NET_DSA_TAG_OCELOT=m
# CONFIG_NET_DSA_TAG_QCA is not set
# CONFIG_NET_DSA_TAG_LAN9303 is not set
# CONFIG_NET_DSA_TAG_SJA1105 is not set
# CONFIG_NET_DSA_TAG_TRAILER is not set
CONFIG_VLAN_8021Q=m
CONFIG_VLAN_8021Q_GVRP=y
CONFIG_VLAN_8021Q_MVRP=y
# CONFIG_DECNET is not set
CONFIG_LLC=m
# CONFIG_LLC2 is not set
# CONFIG_ATALK is not set
# CONFIG_X25 is not set
# CONFIG_LAPB is not set
# CONFIG_PHONET is not set
# CONFIG_6LOWPAN is not set
# CONFIG_IEEE802154 is not set
# CONFIG_NET_SCHED is not set
# CONFIG_DCB is not set
CONFIG_DNS_RESOLVER=y
# CONFIG_BATMAN_ADV is not set
# CONFIG_OPENVSWITCH is not set
# CONFIG_VSOCKETS is not set
# CONFIG_NETLINK_DIAG is not set
# CONFIG_MPLS is not set
# CONFIG_NET_NSH is not set
# CONFIG_HSR is not set
CONFIG_NET_SWITCHDEV=y
# CONFIG_NET_L3_MASTER_DEV is not set
CONFIG_QRTR=m
CONFIG_QRTR_SMD=m
CONFIG_QRTR_TUN=m
# CONFIG_NET_NCSI is not set
CONFIG_RPS=y
CONFIG_RFS_ACCEL=y
CONFIG_XPS=y
# CONFIG_CGROUP_NET_PRIO is not set
# CONFIG_CGROUP_NET_CLASSID is not set
CONFIG_NET_RX_BUSY_POLL=y
CONFIG_BQL=y
CONFIG_BPF_JIT=y
CONFIG_NET_FLOW_LIMIT=y

#
# Network testing
#
# CONFIG_NET_PKTGEN is not set
CONFIG_NET_DROP_MONITOR=y

# end of Network testing
# end of Networking options

# CONFIG_HAMRADIO is not set
CONFIG_CAN=m
CONFIG_CAN_RAW=m
CONFIG_CAN_BCM=m
CONFIG_CAN_GW=m
# CONFIG_CAN_J1939 is not set
# CONFIG_CAN_ISOTP is not set

#
# CAN Device Drivers
#
# CONFIG_CAN_VCAN is not set
# CONFIG_CAN_VXCAN is not set
# CONFIG_CAN_SLCAN is not set
CONFIG_CAN_DEV=m
CONFIG_CAN_CALC_BITTIMING=y
CONFIG_CAN_FLEXCAN=m
# CONFIG_CAN_GRCAN is not set
# CONFIG_CAN_KVASER_PCIEFD is not set
# CONFIG_CAN_XILINXCAN is not set
# CONFIG_CAN_C_CAN is not set
# CONFIG_CAN_CC770 is not set
# CONFIG_CAN_IFI_CANFD is not set
# CONFIG_CAN_M_CAN is not set
# CONFIG_CAN_PEAK_PCIEFD is not set
CONFIG_CAN_RCAR=m
CONFIG_CAN_RCAR_CANFD=m
# CONFIG_CAN_SJA1000 is not set
# CONFIG_CAN_SOFTING is not set

#
# CAN SPI interfaces
#
# CONFIG_CAN_HI311X is not set
# CONFIG_CAN_MCP251X is not set
# CONFIG_CAN_MCP251XFD is not set

# end of CAN SPI interfaces

#
# CAN USB interfaces
#
# CONFIG_CAN_8DEV_USB is not set
# CONFIG_CAN_EMS_USB is not set
# CONFIG_CAN_ESD_USB2 is not set
# CONFIG_CAN_GS_USB is not set
# CONFIG_CAN_KVASER_USB is not set
# CONFIG_CAN_MCBA_USB is not set
# CONFIG_CAN_PEAK_USB is not set
# CONFIG_CAN_UCAN is not set

# end of CAN USB interfaces

# CONFIG_CAN_DEBUG_DEVICES is not set

# end of CAN Device Drivers

CONFIG_BT=m
CONFIG_BT_BREDR=y
# CONFIG_BT_RFCOMM is not set
# CONFIG_BT_BNEP is not set
CONFIG_BT_HIDP=m
# CONFIG_BT_HS is not set
# CONFIG_BT_LE is not set
CONFIG_BT_LEDS=y
# CONFIG_BT_MSFTEXT is not set
# CONFIG_BT_DEBUGFS is not set
# CONFIG_BT_SELFTEST is not set
# CONFIG_BT_FEATURE_DEBUG is not set

#
# Bluetooth device drivers
#
CONFIG_BT_INTEL=m
CONFIG_BT_BCM=m
CONFIG_BT_RTL=m
CONFIG_BT_QCA=m
CONFIG_BT_HCIBTUSB=m
# CONFIG_BT_HCIBTUSB_AUTOSUSPEND is not set
CONFIG_BT_HCIBTUSB_BCM=y
# CONFIG_BT_HCIBTUSB_MTK is not set
CONFIG_BT_HCIBTUSB_RTL=y
# CONFIG_BT_HCIBTSDIO is not set
CONFIG_BT_HCIUART=m
CONFIG_BT_HCIUART_SERDEV=y
CONFIG_BT_HCIUART_H4=y
# CONFIG_BT_HCIUART_NOKIA is not set
# CONFIG_BT_HCIUART_BCSP is not set
# CONFIG_BT_HCIUART_ATH3K is not set
CONFIG_BT_HCIUART_LL=y
# CONFIG_BT_HCIUART_3WIRE is not set
# CONFIG_BT_HCIUART_INTEL is not set
CONFIG_BT_HCIUART_BCM=y
# CONFIG_BT_HCIUART_RTL is not set
CONFIG_BT_HCIUART_QCA=y
# CONFIG_BT_HCIUART_AG6XX is not set
# CONFIG_BT_HCIUART_MRVL is not set
# CONFIG_BT_HCIBCM203X is not set
# CONFIG_BT_HCIBPA10X is not set
# CONFIG_BT_HCIBFUSB is not set
# CONFIG_BT_HCIVHCI is not set
# CONFIG_BT_MRVL is not set
# CONFIG_BT_ATH3K is not set
# CONFIG_BT_MTKSDIO is not set
# CONFIG_BT_MTKUART is not set

# end of Bluetooth device drivers

# CONFIG_AF_RXRPC is not set
# CONFIG_AF_KCM is not set
CONFIG_WIRELESS=y
CONFIG_CFG80211=m
# CONFIG_NL80211_TESTMODE is not set
# CONFIG_CFG80211_DEVELOPER_WARNINGS is not set
CONFIG_CFG80211_REQUIRE_SIGNED_REGDB=y
CONFIG_CFG80211_USE_KERNEL_REGDB_KEYS=y
CONFIG_CFG80211_DEFAULT_PS=y
# CONFIG_CFG80211_DEBUGFS is not set
CONFIG_CFG80211_CRDA_SUPPORT=y
# CONFIG_CFG80211_WEXT is not set
CONFIG_MAC80211=m
CONFIG_MAC80211_HAS_RC=y
CONFIG_MAC80211_RC_MINSTREL=y
CONFIG_MAC80211_RC_DEFAULT_MINSTREL=y
CONFIG_MAC80211_RC_DEFAULT="minstrel_ht"
# CONFIG_MAC80211_MESH is not set
CONFIG_MAC80211_LEDS=y
# CONFIG_MAC80211_DEBUGFS is not set
# CONFIG_MAC80211_MESSAGE_TRACING is not set
# CONFIG_MAC80211_DEBUG_MENU is not set
CONFIG_MAC80211_STA_HASH_MAX_SIZE=0
CONFIG_RFKILL=m
CONFIG_RFKILL_LEDS=y
CONFIG_RFKILL_INPUT=y
# CONFIG_RFKILL_GPIO is not set
CONFIG_NET_9P=y
CONFIG_NET_9P_VIRTIO=y
# CONFIG_NET_9P_XEN is not set
# CONFIG_NET_9P_DEBUG is not set
# CONFIG_CAIF is not set
# CONFIG_CEPH_LIB is not set
# CONFIG_NFC is not set
# CONFIG_PSAMPLE is not set
# CONFIG_NET_IFE is not set
# CONFIG_LWTUNNEL is not set
CONFIG_DST_CACHE=y
CONFIG_GRO_CELLS=y
CONFIG_NET_DEVLINK=y
CONFIG_PAGE_POOL=y
CONFIG_FAILOVER=y
CONFIG_ETHTOOL_NETLINK=y
CONFIG_HAVE_EBPF_JIT=y

#
# Device Drivers
#
CONFIG_ARM_AMBA=y
CONFIG_TEGRA_AHB=y
CONFIG_HAVE_PCI=y
CONFIG_PCI=y
CONFIG_PCI_DOMAINS=y
CONFIG_PCI_DOMAINS_GENERIC=y
CONFIG_PCI_SYSCALL=y
CONFIG_PCIEPORTBUS=y
# CONFIG_HOTPLUG_PCI_PCIE is not set
# CONFIG_PCIEAER is not set
CONFIG_PCIEASPM=y
CONFIG_PCIEASPM_DEFAULT=y
# CONFIG_PCIEASPM_POWERSAVE is not set
# CONFIG_PCIEASPM_POWER_SUPERSAVE is not set
# CONFIG_PCIEASPM_PERFORMANCE is not set
CONFIG_PCIE_PME=y
# CONFIG_PCIE_PTM is not set
# CONFIG_PCIE_BW is not set
CONFIG_PCI_MSI=y
CONFIG_PCI_MSI_IRQ_DOMAIN=y
CONFIG_PCI_MSI_ARCH_FALLBACKS=y
CONFIG_PCI_QUIRKS=y
# CONFIG_PCI_DEBUG is not set
# CONFIG_PCI_REALLOC_ENABLE_AUTO is not set
# CONFIG_PCI_STUB is not set
# CONFIG_PCI_PF_STUB is not set
CONFIG_PCI_ATS=y
CONFIG_PCI_ECAM=y
CONFIG_PCI_BRIDGE_EMUL=y
CONFIG_PCI_IOV=y
# CONFIG_PCI_PRI is not set
CONFIG_PCI_PASID=y
CONFIG_PCI_LABEL=y
CONFIG_HOTPLUG_PCI=y
CONFIG_HOTPLUG_PCI_ACPI=y
# CONFIG_HOTPLUG_PCI_ACPI_IBM is not set
# CONFIG_HOTPLUG_PCI_CPCI is not set
# CONFIG_HOTPLUG_PCI_SHPC is not set

#
# PCI controller drivers
#
CONFIG_PCI_AARDVARK=y
# CONFIG_PCIE_XILINX_NWL is not set
# CONFIG_PCI_FTPCI100 is not set
CONFIG_PCI_TEGRA=y
# CONFIG_PCIE_RCAR is not set
CONFIG_PCIE_RCAR_HOST=y
CONFIG_PCI_HOST_COMMON=y
CONFIG_PCI_HOST_GENERIC=y
# CONFIG_PCIE_XILINX is not set
# CONFIG_PCIE_XILINX_CPM is not set
CONFIG_PCI_XGENE=y
CONFIG_PCI_XGENE_MSI=y
CONFIG_PCIE_IPROC=y
CONFIG_PCIE_IPROC_PLATFORM=y
CONFIG_PCIE_IPROC_MSI=y
CONFIG_PCIE_ALTERA=y
CONFIG_PCIE_ALTERA_MSI=y
CONFIG_PCI_HOST_THUNDER_PEM=y
CONFIG_PCI_HOST_THUNDER_ECAM=y
CONFIG_PCIE_ROCKCHIP=y
CONFIG_PCIE_ROCKCHIP_HOST=m
# CONFIG_PCIE_MEDIATEK is not set
CONFIG_PCIE_BRCMSTB=m
# CONFIG_PCIE_HISI_ERR is not set

#
# DesignWare PCI Core Support
#
CONFIG_PCIE_DW=y
CONFIG_PCIE_DW_HOST=y
# CONFIG_PCIE_DW_PLAT_HOST is not set
# CONFIG_PCI_IMX6 is not set
# CONFIG_PCI_KEYSTONE_HOST is not set
CONFIG_PCI_LAYERSCAPE=y
CONFIG_PCI_HISI=y
CONFIG_PCIE_QCOM=y
CONFIG_PCIE_ARMADA_8K=y
CONFIG_PCIE_KIRIN=y
CONFIG_PCIE_HISI_STB=y
# CONFIG_PCI_MESON is not set
CONFIG_PCIE_TEGRA194=m
CONFIG_PCIE_TEGRA194_HOST=m
# CONFIG_PCIE_UNIPHIER is not set
# CONFIG_PCIE_AL is not set

# end of DesignWare PCI Core Support

#
# Mobiveil PCIe Core Support
#
CONFIG_PCIE_MOBIVEIL=y
CONFIG_PCIE_MOBIVEIL_HOST=y
# CONFIG_PCIE_MOBIVEIL_PLAT is not set
CONFIG_PCIE_LAYERSCAPE_GEN4=y

# end of Mobiveil PCIe Core Support

#
# Cadence PCIe controllers support
#
# CONFIG_PCIE_CADENCE_PLAT_HOST is not set
# CONFIG_PCI_J721E_HOST is not set

# end of Cadence PCIe controllers support
# end of PCI controller drivers

#
# PCI Endpoint
#
# CONFIG_PCI_ENDPOINT is not set

# end of PCI Endpoint

#
# PCI switch controller drivers
#
# CONFIG_PCI_SW_SWITCHTEC is not set

# end of PCI switch controller drivers

# CONFIG_PCCARD is not set
# CONFIG_RAPIDIO is not set

#
# Generic Driver Options
#
# CONFIG_UEVENT_HELPER is not set
CONFIG_DEVTMPFS=y
CONFIG_DEVTMPFS_MOUNT=y
CONFIG_STANDALONE=y
CONFIG_PREVENT_FIRMWARE_BUILD=y

#
# Firmware loader
#
CONFIG_FW_LOADER=y
CONFIG_FW_LOADER_PAGED_BUF=y
CONFIG_EXTRA_FIRMWARE=""
CONFIG_FW_LOADER_USER_HELPER=y
CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y
# CONFIG_FW_LOADER_COMPRESS is not set
CONFIG_FW_CACHE=y

# end of Firmware loader

CONFIG_WANT_DEV_COREDUMP=y
CONFIG_ALLOW_DEV_COREDUMP=y
CONFIG_DEV_COREDUMP=y
# CONFIG_DEBUG_DRIVER is not set
# CONFIG_DEBUG_DEVRES is not set
# CONFIG_DEBUG_TEST_DRIVER_REMOVE is not set
# CONFIG_PM_QOS_KUNIT_TEST is not set
CONFIG_TEST_ASYNC_DRIVER_PROBE=m
# CONFIG_KUNIT_DRIVER_PE_TEST is not set
CONFIG_SYS_HYPERVISOR=y
CONFIG_GENERIC_CPU_AUTOPROBE=y
CONFIG_GENERIC_CPU_VULNERABILITIES=y
CONFIG_SOC_BUS=y
CONFIG_REGMAP=y
CONFIG_REGMAP_I2C=y
CONFIG_REGMAP_SLIMBUS=m
CONFIG_REGMAP_SPI=y
CONFIG_REGMAP_SPMI=y
CONFIG_REGMAP_MMIO=y
CONFIG_REGMAP_IRQ=y
CONFIG_REGMAP_SOUNDWIRE=m
CONFIG_DMA_SHARED_BUFFER=y
CONFIG_DMA_FENCE_TRACE=y
CONFIG_GENERIC_ARCH_TOPOLOGY=y

# end of Generic Driver Options

#
# Bus devices
#
CONFIG_BRCMSTB_GISB_ARB=y
# CONFIG_MOXTET is not set
CONFIG_HISILICON_LPC=y
# CONFIG_IMX_WEIM is not set
CONFIG_QCOM_EBI2=y
CONFIG_SIMPLE_PM_BUS=y
CONFIG_SUN50I_DE2_BUS=y
CONFIG_SUNXI_RSB=y
# CONFIG_TEGRA_ACONNECT is not set
# CONFIG_TEGRA_GMI is not set
CONFIG_UNIPHIER_SYSTEM_BUS=y
CONFIG_VEXPRESS_CONFIG=y
CONFIG_FSL_MC_BUS=y
# CONFIG_MHI_BUS is not set

# end of Bus devices

# CONFIG_CONNECTOR is not set
# CONFIG_GNSS is not set
CONFIG_MTD=y
# CONFIG_MTD_TESTS is not set

#
# Partition parsers
#
# CONFIG_MTD_AR7_PARTS is not set
# CONFIG_MTD_CMDLINE_PARTS is not set
CONFIG_MTD_OF_PARTS=y
# CONFIG_MTD_AFS_PARTS is not set
# CONFIG_MTD_REDBOOT_PARTS is not set

# end of Partition parsers

#
# User Modules And Translation Layers
#
CONFIG_MTD_BLKDEVS=y
CONFIG_MTD_BLOCK=y
# CONFIG_FTL is not set
# CONFIG_NFTL is not set
# CONFIG_INFTL is not set
# CONFIG_RFD_FTL is not set
# CONFIG_SSFDC is not set
# CONFIG_SM_FTL is not set
# CONFIG_MTD_OOPS is not set
# CONFIG_MTD_SWAP is not set
# CONFIG_MTD_PARTITIONED_MASTER is not set

#
# RAM/ROM/Flash chip drivers
#
CONFIG_MTD_CFI=y
# CONFIG_MTD_JEDECPROBE is not set
CONFIG_MTD_GEN_PROBE=y
CONFIG_MTD_CFI_ADV_OPTIONS=y
CONFIG_MTD_CFI_NOSWAP=y
# CONFIG_MTD_CFI_BE_BYTE_SWAP is not set
# CONFIG_MTD_CFI_LE_BYTE_SWAP is not set
# CONFIG_MTD_CFI_GEOMETRY is not set
CONFIG_MTD_MAP_BANK_WIDTH_1=y
CONFIG_MTD_MAP_BANK_WIDTH_2=y
CONFIG_MTD_MAP_BANK_WIDTH_4=y
CONFIG_MTD_CFI_I1=y
CONFIG_MTD_CFI_I2=y
# CONFIG_MTD_OTP is not set
CONFIG_MTD_CFI_INTELEXT=y
CONFIG_MTD_CFI_AMDSTD=y
CONFIG_MTD_CFI_STAA=y
CONFIG_MTD_CFI_UTIL=y
# CONFIG_MTD_RAM is not set
# CONFIG_MTD_ROM is not set
# CONFIG_MTD_ABSENT is not set

# end of RAM/ROM/Flash chip drivers

#
# Mapping drivers for chip access
#
# CONFIG_MTD_COMPLEX_MAPPINGS is not set
CONFIG_MTD_PHYSMAP=y
# CONFIG_MTD_PHYSMAP_COMPAT is not set
CONFIG_MTD_PHYSMAP_OF=y
# CONFIG_MTD_PHYSMAP_VERSATILE is not set
# CONFIG_MTD_PHYSMAP_GEMINI is not set
# CONFIG_MTD_INTEL_VR_NOR is not set
# CONFIG_MTD_PLATRAM is not set

# end of Mapping drivers for chip access

#
# Self-contained MTD device drivers
#
# CONFIG_MTD_PMC551 is not set
CONFIG_MTD_DATAFLASH=y
# CONFIG_MTD_DATAFLASH_WRITE_VERIFY is not set
# CONFIG_MTD_DATAFLASH_OTP is not set
# CONFIG_MTD_MCHP23K256 is not set
CONFIG_MTD_SST25L=y
# CONFIG_MTD_SLRAM is not set
# CONFIG_MTD_PHRAM is not set
# CONFIG_MTD_MTDRAM is not set
# CONFIG_MTD_BLOCK2MTD is not set

#
# Disk-On-Chip Device Drivers
#
# CONFIG_MTD_DOCG3 is not set

# end of Self-contained MTD device drivers

#
# NAND
#
CONFIG_MTD_NAND_CORE=y
# CONFIG_MTD_ONENAND is not set
CONFIG_MTD_RAW_NAND=y

#
# Raw/parallel NAND flash controllers
#
CONFIG_MTD_NAND_DENALI=y
# CONFIG_MTD_NAND_DENALI_PCI is not set
CONFIG_MTD_NAND_DENALI_DT=y
# CONFIG_MTD_NAND_CAFE is not set
CONFIG_MTD_NAND_MARVELL=y
# CONFIG_MTD_NAND_BRCMNAND is not set
CONFIG_MTD_NAND_FSL_IFC=y
# CONFIG_MTD_NAND_MXC is not set
# CONFIG_MTD_NAND_SUNXI is not set
# CONFIG_MTD_NAND_HISI504 is not set
CONFIG_MTD_NAND_QCOM=y
# CONFIG_MTD_NAND_MTK is not set
# CONFIG_MTD_NAND_MXIC is not set
# CONFIG_MTD_NAND_TEGRA is not set
# CONFIG_MTD_NAND_MESON is not set
# CONFIG_MTD_NAND_GPIO is not set
# CONFIG_MTD_NAND_PLATFORM is not set
# CONFIG_MTD_NAND_CADENCE is not set
# CONFIG_MTD_NAND_ARASAN is not set

#
# Misc
#
# CONFIG_MTD_NAND_NANDSIM is not set
# CONFIG_MTD_NAND_RICOH is not set
# CONFIG_MTD_NAND_DISKONCHIP is not set
# CONFIG_MTD_SPI_NAND is not set

#
# ECC engine support
#
CONFIG_MTD_NAND_ECC=y
CONFIG_MTD_NAND_ECC_SW_HAMMING=y
# CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC is not set
# CONFIG_MTD_NAND_ECC_SW_BCH is not set

# end of ECC engine support
# end of NAND

#
# LPDDR & LPDDR2 PCM memory drivers
#
# CONFIG_MTD_LPDDR is not set

# end of LPDDR & LPDDR2 PCM memory drivers

CONFIG_MTD_SPI_NOR=y
CONFIG_MTD_SPI_NOR_USE_4K_SECTORS=y
# CONFIG_SPI_HISI_SFC is not set
# CONFIG_MTD_UBI is not set
# CONFIG_MTD_HYPERBUS is not set
CONFIG_DTC=y
CONFIG_OF=y
# CONFIG_OF_UNITTEST is not set
CONFIG_OF_FLATTREE=y
CONFIG_OF_EARLY_FLATTREE=y
CONFIG_OF_KOBJ=y
CONFIG_OF_DYNAMIC=y
CONFIG_OF_ADDRESS=y
CONFIG_OF_IRQ=y
CONFIG_OF_NET=y
CONFIG_OF_RESERVED_MEM=y
CONFIG_OF_RESOLVE=y
CONFIG_OF_OVERLAY=y
CONFIG_OF_NUMA=y
# CONFIG_PARPORT is not set
CONFIG_PNP=y
CONFIG_PNP_DEBUG_MESSAGES=y

#
# Protocols
#
CONFIG_PNPACPI=y
CONFIG_BLK_DEV=y
# CONFIG_BLK_DEV_NULL_BLK is not set
# CONFIG_BLK_DEV_PCIESSD_MTIP32XX is not set
# CONFIG_BLK_DEV_UMEM is not set
CONFIG_BLK_DEV_LOOP=y
CONFIG_BLK_DEV_LOOP_MIN_COUNT=8
# CONFIG_BLK_DEV_CRYPTOLOOP is not set
# CONFIG_BLK_DEV_DRBD is not set
CONFIG_BLK_DEV_NBD=m
# CONFIG_BLK_DEV_SKD is not set
# CONFIG_BLK_DEV_SX8 is not set
# CONFIG_BLK_DEV_RAM is not set
# CONFIG_CDROM_PKTCDVD is not set
# CONFIG_ATA_OVER_ETH is not set
CONFIG_XEN_BLKDEV_FRONTEND=y
# CONFIG_XEN_BLKDEV_BACKEND is not set
CONFIG_VIRTIO_BLK=y
# CONFIG_BLK_DEV_RBD is not set
# CONFIG_BLK_DEV_RSXX is not set

#
# NVME Support
#
CONFIG_NVME_CORE=m
CONFIG_BLK_DEV_NVME=m
# CONFIG_NVME_MULTIPATH is not set
# CONFIG_NVME_HWMON is not set
# CONFIG_NVME_FC is not set
# CONFIG_NVME_TCP is not set
# CONFIG_NVME_TARGET is not set

# end of NVME Support

#
# Misc devices
#
# CONFIG_AD525X_DPOT is not set
# CONFIG_DUMMY_IRQ is not set
# CONFIG_PHANTOM is not set
# CONFIG_TIFM_CORE is not set
# CONFIG_ICS932S401 is not set
# CONFIG_ENCLOSURE_SERVICES is not set
# CONFIG_HP_ILO is not set
# CONFIG_QCOM_COINCELL is not set
# CONFIG_QCOM_FASTRPC is not set
# CONFIG_APDS9802ALS is not set
# CONFIG_ISL29003 is not set
# CONFIG_ISL29020 is not set
# CONFIG_SENSORS_TSL2550 is not set
# CONFIG_SENSORS_BH1770 is not set
# CONFIG_SENSORS_APDS990X is not set
# CONFIG_HMC6352 is not set
# CONFIG_DS1682 is not set
# CONFIG_LATTICE_ECP3_CONFIG is not set
CONFIG_SRAM=y
# CONFIG_PCI_ENDPOINT_TEST is not set
# CONFIG_XILINX_SDFEC is not set
# CONFIG_PVPANIC is not set
# CONFIG_HISI_HIKEY_USB is not set
# CONFIG_C2PORT is not set

#
# EEPROM support
#
CONFIG_EEPROM_AT24=m
CONFIG_EEPROM_AT25=m
# CONFIG_EEPROM_LEGACY is not set
# CONFIG_EEPROM_MAX6875 is not set
# CONFIG_EEPROM_93CX6 is not set
# CONFIG_EEPROM_93XX46 is not set
# CONFIG_EEPROM_IDT_89HPESX is not set
# CONFIG_EEPROM_EE1004 is not set

# end of EEPROM support

# CONFIG_CB710_CORE is not set

#
# Texas Instruments shared transport line discipline #
# CONFIG_TI_ST is not set

# end of Texas Instruments shared transport line discipline

# CONFIG_SENSORS_LIS3_I2C is not set
# CONFIG_ALTERA_STAPL is not set
# CONFIG_GENWQE is not set
# CONFIG_ECHO is not set
# CONFIG_MISC_ALCOR_PCI is not set
# CONFIG_MISC_RTSX_PCI is not set
# CONFIG_MISC_RTSX_USB is not set
# CONFIG_HABANA_AI is not set
CONFIG_UACCE=m

# end of Misc devices

#
# SCSI device support
#
CONFIG_SCSI_MOD=y
CONFIG_RAID_ATTRS=m
CONFIG_SCSI=y
CONFIG_SCSI_DMA=y
# CONFIG_SCSI_PROC_FS is not set

#
# SCSI support type (disk, tape, CD-ROM)
#
CONFIG_BLK_DEV_SD=y
# CONFIG_CHR_DEV_ST is not set
# CONFIG_BLK_DEV_SR is not set
# CONFIG_CHR_DEV_SG is not set
# CONFIG_CHR_DEV_SCH is not set
# CONFIG_SCSI_CONSTANTS is not set
# CONFIG_SCSI_LOGGING is not set
# CONFIG_SCSI_SCAN_ASYNC is not set

#
# SCSI Transports
#
# CONFIG_SCSI_SPI_ATTRS is not set
# CONFIG_SCSI_FC_ATTRS is not set
# CONFIG_SCSI_ISCSI_ATTRS is not set
CONFIG_SCSI_SAS_ATTRS=y
CONFIG_SCSI_SAS_LIBSAS=y
CONFIG_SCSI_SAS_ATA=y
CONFIG_SCSI_SAS_HOST_SMP=y
# CONFIG_SCSI_SRP_ATTRS is not set

# end of SCSI Transports

CONFIG_SCSI_LOWLEVEL=y
# CONFIG_ISCSI_TCP is not set
# CONFIG_ISCSI_BOOT_SYSFS is not set
# CONFIG_SCSI_CXGB3_ISCSI is not set
# CONFIG_SCSI_CXGB4_ISCSI is not set
# CONFIG_SCSI_BNX2_ISCSI is not set
# CONFIG_BE2ISCSI is not set
# CONFIG_BLK_DEV_3W_XXXX_RAID is not set
# CONFIG_SCSI_HPSA is not set
# CONFIG_SCSI_3W_9XXX is not set
# CONFIG_SCSI_3W_SAS is not set
# CONFIG_SCSI_ACARD is not set
# CONFIG_SCSI_AACRAID is not set
# CONFIG_SCSI_AIC7XXX is not set
# CONFIG_SCSI_AIC79XX is not set
# CONFIG_SCSI_AIC94XX is not set
CONFIG_SCSI_HISI_SAS=y
CONFIG_SCSI_HISI_SAS_PCI=y
# CONFIG_SCSI_MVSAS is not set
# CONFIG_SCSI_MVUMI is not set
# CONFIG_SCSI_ADVANSYS is not set
# CONFIG_SCSI_ARCMSR is not set
# CONFIG_SCSI_ESAS2R is not set
# CONFIG_MEGARAID_NEWGEN is not set
# CONFIG_MEGARAID_LEGACY is not set
CONFIG_MEGARAID_SAS=y
CONFIG_SCSI_MPT3SAS=m
CONFIG_SCSI_MPT2SAS_MAX_SGE=128
CONFIG_SCSI_MPT3SAS_MAX_SGE=128
# CONFIG_SCSI_MPT2SAS is not set
# CONFIG_SCSI_SMARTPQI is not set
CONFIG_SCSI_UFSHCD=y
# CONFIG_SCSI_UFSHCD_PCI is not set
CONFIG_SCSI_UFSHCD_PLATFORM=y
# CONFIG_SCSI_UFS_CDNS_PLATFORM is not set
# CONFIG_SCSI_UFS_DWC_TC_PLATFORM is not set
CONFIG_SCSI_UFS_QCOM=m
# CONFIG_SCSI_UFS_MEDIATEK is not set
CONFIG_SCSI_UFS_HISI=y
# CONFIG_SCSI_UFS_TI_J721E is not set
# CONFIG_SCSI_UFS_BSG is not set
# CONFIG_SCSI_UFS_EXYNOS is not set
# CONFIG_SCSI_HPTIOP is not set
# CONFIG_SCSI_MYRB is not set
# CONFIG_SCSI_MYRS is not set
# CONFIG_XEN_SCSI_FRONTEND is not set
# CONFIG_SCSI_SNIC is not set
# CONFIG_SCSI_DMX3191D is not set
# CONFIG_SCSI_FDOMAIN_PCI is not set
# CONFIG_SCSI_GDTH is not set
# CONFIG_SCSI_IPS is not set
# CONFIG_SCSI_INITIO is not set
# CONFIG_SCSI_INIA100 is not set
# CONFIG_SCSI_STEX is not set
# CONFIG_SCSI_SYM53C8XX_2 is not set
# CONFIG_SCSI_IPR is not set
# CONFIG_SCSI_QLOGIC_1280 is not set
# CONFIG_SCSI_QLA_ISCSI is not set
# CONFIG_SCSI_DC395x is not set
# CONFIG_SCSI_AM53C974 is not set
# CONFIG_SCSI_WD719X is not set
# CONFIG_SCSI_DEBUG is not set
# CONFIG_SCSI_PMCRAID is not set
# CONFIG_SCSI_PM8001 is not set
CONFIG_SCSI_VIRTIO=y
# CONFIG_SCSI_DH is not set

# end of SCSI device support

CONFIG_HAVE_PATA_PLATFORM=y
CONFIG_ATA=y
CONFIG_SATA_HOST=y
CONFIG_PATA_TIMINGS=y
CONFIG_ATA_VERBOSE_ERROR=y
CONFIG_ATA_FORCE=y
CONFIG_ATA_ACPI=y
# CONFIG_SATA_ZPODD is not set
CONFIG_SATA_PMP=y

#
# Controllers with non-SFF native interface
#
CONFIG_SATA_AHCI=y
CONFIG_SATA_MOBILE_LPM_POLICY=0
CONFIG_SATA_AHCI_PLATFORM=y
# CONFIG_AHCI_BRCM is not set
# CONFIG_AHCI_IMX is not set
CONFIG_AHCI_CEVA=y
# CONFIG_AHCI_MTK is not set
CONFIG_AHCI_MVEBU=y
# CONFIG_AHCI_SUNXI is not set
# CONFIG_AHCI_TEGRA is not set
CONFIG_AHCI_XGENE=y
CONFIG_AHCI_QORIQ=y
# CONFIG_SATA_AHCI_SEATTLE is not set
# CONFIG_SATA_INIC162X is not set
# CONFIG_SATA_ACARD_AHCI is not set
CONFIG_SATA_SIL24=y
CONFIG_ATA_SFF=y

#
# SFF controllers with custom DMA interface
#
# CONFIG_PDC_ADMA is not set
# CONFIG_SATA_QSTOR is not set
# CONFIG_SATA_SX4 is not set
CONFIG_ATA_BMDMA=y

#
# SATA SFF controllers with BMDMA
#
# CONFIG_ATA_PIIX is not set
# CONFIG_SATA_DWC is not set
# CONFIG_SATA_MV is not set
# CONFIG_SATA_NV is not set
# CONFIG_SATA_PROMISE is not set
CONFIG_SATA_RCAR=y
# CONFIG_SATA_SIL is not set
# CONFIG_SATA_SIS is not set
# CONFIG_SATA_SVW is not set
# CONFIG_SATA_ULI is not set
# CONFIG_SATA_VIA is not set
# CONFIG_SATA_VITESSE is not set

#
# PATA SFF controllers with BMDMA
#
# CONFIG_PATA_ALI is not set
# CONFIG_PATA_AMD is not set
# CONFIG_PATA_ARTOP is not set
# CONFIG_PATA_ATIIXP is not set
# CONFIG_PATA_ATP867X is not set
# CONFIG_PATA_CMD64X is not set
# CONFIG_PATA_CYPRESS is not set
# CONFIG_PATA_EFAR is not set
# CONFIG_PATA_HPT366 is not set
# CONFIG_PATA_HPT37X is not set
# CONFIG_PATA_HPT3X2N is not set
# CONFIG_PATA_HPT3X3 is not set
# CONFIG_PATA_IMX is not set
# CONFIG_PATA_IT8213 is not set
# CONFIG_PATA_IT821X is not set
# CONFIG_PATA_JMICRON is not set
# CONFIG_PATA_MARVELL is not set
# CONFIG_PATA_NETCELL is not set
# CONFIG_PATA_NINJA32 is not set
# CONFIG_PATA_NS87415 is not set
# CONFIG_PATA_OLDPIIX is not set
# CONFIG_PATA_OPTIDMA is not set
# CONFIG_PATA_PDC2027X is not set
# CONFIG_PATA_PDC_OLD is not set
# CONFIG_PATA_RADISYS is not set
# CONFIG_PATA_RDC is not set
# CONFIG_PATA_SCH is not set
# CONFIG_PATA_SERVERWORKS is not set
# CONFIG_PATA_SIL680 is not set
# CONFIG_PATA_SIS is not set
# CONFIG_PATA_TOSHIBA is not set
# CONFIG_PATA_TRIFLEX is not set
# CONFIG_PATA_VIA is not set
# CONFIG_PATA_WINBOND is not set

#
# PIO-only SFF controllers
#
# CONFIG_PATA_CMD640_PCI is not set
# CONFIG_PATA_MPIIX is not set
# CONFIG_PATA_NS87410 is not set
# CONFIG_PATA_OPTI is not set
CONFIG_PATA_PLATFORM=y
CONFIG_PATA_OF_PLATFORM=y
# CONFIG_PATA_RZ1000 is not set

#
# Generic fallback / legacy drivers
#
# CONFIG_PATA_ACPI is not set
# CONFIG_ATA_GENERIC is not set
# CONFIG_PATA_LEGACY is not set
CONFIG_MD=y
CONFIG_BLK_DEV_MD=m
# CONFIG_MD_LINEAR is not set
# CONFIG_MD_RAID0 is not set
# CONFIG_MD_RAID1 is not set
# CONFIG_MD_RAID10 is not set
# CONFIG_MD_RAID456 is not set
# CONFIG_MD_MULTIPATH is not set
# CONFIG_MD_FAULTY is not set
# CONFIG_BCACHE is not set
CONFIG_BLK_DEV_DM_BUILTIN=y
CONFIG_BLK_DEV_DM=m
# CONFIG_DM_DEBUG is not set
# CONFIG_DM_UNSTRIPED is not set
# CONFIG_DM_CRYPT is not set
# CONFIG_DM_SNAPSHOT is not set
# CONFIG_DM_THIN_PROVISIONING is not set
# CONFIG_DM_CACHE is not set
# CONFIG_DM_WRITECACHE is not set
# CONFIG_DM_EBS is not set
# CONFIG_DM_ERA is not set
# CONFIG_DM_CLONE is not set
CONFIG_DM_MIRROR=m
# CONFIG_DM_LOG_USERSPACE is not set
# CONFIG_DM_RAID is not set
CONFIG_DM_ZERO=m
# CONFIG_DM_MULTIPATH is not set
# CONFIG_DM_DELAY is not set
# CONFIG_DM_DUST is not set
# CONFIG_DM_UEVENT is not set
# CONFIG_DM_FLAKEY is not set
# CONFIG_DM_VERITY is not set
# CONFIG_DM_SWITCH is not set
# CONFIG_DM_LOG_WRITES is not set
# CONFIG_DM_INTEGRITY is not set
# CONFIG_TARGET_CORE is not set
# CONFIG_FUSION is not set

#
# IEEE 1394 (FireWire) support
#
# CONFIG_FIREWIRE is not set
# CONFIG_FIREWIRE_NOSY is not set

# end of IEEE 1394 (FireWire) support

CONFIG_NETDEVICES=y
CONFIG_MII=y
CONFIG_NET_CORE=y
# CONFIG_BONDING is not set
# CONFIG_DUMMY is not set
# CONFIG_WIREGUARD is not set
# CONFIG_EQUALIZER is not set
# CONFIG_NET_FC is not set
# CONFIG_NET_TEAM is not set
CONFIG_MACVLAN=m
CONFIG_MACVTAP=m
# CONFIG_IPVLAN is not set
# CONFIG_VXLAN is not set
# CONFIG_GENEVE is not set
# CONFIG_BAREUDP is not set
# CONFIG_GTP is not set
# CONFIG_MACSEC is not set
# CONFIG_NETCONSOLE is not set
CONFIG_TUN=y
CONFIG_TAP=m
# CONFIG_TUN_VNET_CROSS_LE is not set
CONFIG_VETH=m
CONFIG_VIRTIO_NET=y
# CONFIG_NLMON is not set
# CONFIG_ARCNET is not set

#
# Distributed Switch Architecture drivers
#
# CONFIG_B53 is not set
# CONFIG_NET_DSA_BCM_SF2 is not set
# CONFIG_NET_DSA_LOOP is not set
# CONFIG_NET_DSA_HIRSCHMANN_HELLCREEK is not set # CONFIG_NET_DSA_LANTIQ_GSWIP is not set
# CONFIG_NET_DSA_MT7530 is not set
# CONFIG_NET_DSA_MV88E6060 is not set
# CONFIG_NET_DSA_MICROCHIP_KSZ9477 is not set # CONFIG_NET_DSA_MICROCHIP_KSZ8795 is not set # CONFIG_NET_DSA_MV88E6XXX is not set CONFIG_NET_DSA_MSCC_FELIX=m
# CONFIG_NET_DSA_MSCC_SEVILLE is not set
# CONFIG_NET_DSA_AR9331 is not set
# CONFIG_NET_DSA_SJA1105 is not set
# CONFIG_NET_DSA_QCA8K is not set
# CONFIG_NET_DSA_REALTEK_SMI is not set
# CONFIG_NET_DSA_SMSC_LAN9303_I2C is not set # CONFIG_NET_DSA_SMSC_LAN9303_MDIO is not set # CONFIG_NET_DSA_VITESSE_VSC73XX_SPI is not set # CONFIG_NET_DSA_VITESSE_VSC73XX_PLATFORM is not set

# end of Distributed Switch Architecture drivers

CONFIG_ETHERNET=y
CONFIG_MDIO=m
CONFIG_NET_VENDOR_3COM=y
# CONFIG_VORTEX is not set
# CONFIG_TYPHOON is not set
CONFIG_NET_VENDOR_ADAPTEC=y
# CONFIG_ADAPTEC_STARFIRE is not set
CONFIG_NET_VENDOR_AGERE=y
# CONFIG_ET131X is not set
CONFIG_NET_VENDOR_ALACRITECH=y
# CONFIG_SLICOSS is not set
CONFIG_NET_VENDOR_ALLWINNER=y
# CONFIG_SUN4I_EMAC is not set
CONFIG_NET_VENDOR_ALTEON=y
# CONFIG_ACENIC is not set
# CONFIG_ALTERA_TSE is not set
CONFIG_NET_VENDOR_AMAZON=y
# CONFIG_ENA_ETHERNET is not set
CONFIG_NET_VENDOR_AMD=y
# CONFIG_AMD8111_ETH is not set
# CONFIG_PCNET32 is not set
CONFIG_AMD_XGBE=y
CONFIG_NET_XGENE=y
# CONFIG_NET_XGENE_V2 is not set
CONFIG_NET_VENDOR_AQUANTIA=y
# CONFIG_AQTION is not set
CONFIG_NET_VENDOR_ARC=y
# CONFIG_EMAC_ROCKCHIP is not set
CONFIG_NET_VENDOR_ATHEROS=y
# CONFIG_ATL2 is not set
# CONFIG_ATL1 is not set
# CONFIG_ATL1E is not set
CONFIG_ATL1C=m
# CONFIG_ALX is not set
CONFIG_NET_VENDOR_AURORA=y
# CONFIG_AURORA_NB8800 is not set
CONFIG_NET_VENDOR_BROADCOM=y
# CONFIG_B44 is not set
CONFIG_BCMGENET=m
# CONFIG_BNX2 is not set
# CONFIG_CNIC is not set
# CONFIG_TIGON3 is not set
CONFIG_BNX2X=m
CONFIG_BNX2X_SRIOV=y
CONFIG_BGMAC=y
CONFIG_BGMAC_PLATFORM=y
# CONFIG_SYSTEMPORT is not set
# CONFIG_BNXT is not set
CONFIG_NET_VENDOR_BROCADE=y
# CONFIG_BNA is not set
CONFIG_NET_VENDOR_CADENCE=y
CONFIG_MACB=y
CONFIG_MACB_USE_HWSTAMP=y
# CONFIG_MACB_PCI is not set
CONFIG_NET_VENDOR_CAVIUM=y
CONFIG_THUNDER_NIC_PF=y
# CONFIG_THUNDER_NIC_VF is not set
CONFIG_THUNDER_NIC_BGX=y
CONFIG_THUNDER_NIC_RGX=y
# CONFIG_CAVIUM_PTP is not set
# CONFIG_LIQUIDIO is not set
# CONFIG_LIQUIDIO_VF is not set
CONFIG_NET_VENDOR_CHELSIO=y
# CONFIG_CHELSIO_T1 is not set
# CONFIG_CHELSIO_T3 is not set
# CONFIG_CHELSIO_T4 is not set
# CONFIG_CHELSIO_T4VF is not set
CONFIG_NET_VENDOR_CISCO=y
# CONFIG_ENIC is not set
CONFIG_NET_VENDOR_CORTINA=y
# CONFIG_GEMINI_ETHERNET is not set
# CONFIG_DNET is not set
CONFIG_NET_VENDOR_DEC=y
# CONFIG_NET_TULIP is not set
CONFIG_NET_VENDOR_DLINK=y
# CONFIG_DL2K is not set
# CONFIG_SUNDANCE is not set
CONFIG_NET_VENDOR_EMULEX=y
# CONFIG_BE2NET is not set
CONFIG_NET_VENDOR_EZCHIP=y
# CONFIG_EZCHIP_NPS_MANAGEMENT_ENET is not set
CONFIG_NET_VENDOR_FREESCALE=y
CONFIG_FEC=y
CONFIG_FSL_FMAN=y
CONFIG_DPAA_ERRATUM_A050385=y
# CONFIG_FSL_PQ_MDIO is not set
# CONFIG_FSL_XGMAC_MDIO is not set
# CONFIG_GIANFAR is not set
CONFIG_FSL_DPAA_ETH=y
CONFIG_FSL_DPAA2_ETH=y
CONFIG_FSL_DPAA2_PTP_CLOCK=y
CONFIG_FSL_ENETC=y
CONFIG_FSL_ENETC_VF=y
CONFIG_FSL_ENETC_MDIO=y
CONFIG_FSL_ENETC_PTP_CLOCK=y
CONFIG_NET_VENDOR_GOOGLE=y
# CONFIG_GVE is not set
CONFIG_NET_VENDOR_HISILICON=y
CONFIG_HIX5HD2_GMAC=y
# CONFIG_HISI_FEMAC is not set
# CONFIG_HIP04_ETH is not set
CONFIG_HNS_MDIO=y
CONFIG_HNS=y
CONFIG_HNS_DSAF=y
CONFIG_HNS_ENET=y
CONFIG_HNS3=y
CONFIG_HNS3_HCLGE=y
# CONFIG_HNS3_HCLGEVF is not set
CONFIG_HNS3_ENET=y
CONFIG_NET_VENDOR_HUAWEI=y
# CONFIG_HINIC is not set
CONFIG_NET_VENDOR_I825XX=y
CONFIG_NET_VENDOR_INTEL=y
# CONFIG_E100 is not set
CONFIG_E1000=y
CONFIG_E1000E=y
CONFIG_IGB=y
CONFIG_IGB_HWMON=y
CONFIG_IGBVF=y
# CONFIG_IXGB is not set
# CONFIG_IXGBE is not set
# CONFIG_IXGBEVF is not set
# CONFIG_I40E is not set
# CONFIG_I40EVF is not set
# CONFIG_ICE is not set
# CONFIG_FM10K is not set
# CONFIG_IGC is not set
# CONFIG_JME is not set
CONFIG_NET_VENDOR_MARVELL=y
CONFIG_MVMDIO=y
CONFIG_MVNETA=y
CONFIG_MVPP2=y
# CONFIG_PXA168_ETH is not set
# CONFIG_SKGE is not set
CONFIG_SKY2=y
# CONFIG_SKY2_DEBUG is not set
# CONFIG_OCTEONTX2_AF is not set
# CONFIG_OCTEONTX2_PF is not set
# CONFIG_PRESTERA is not set
# CONFIG_NET_VENDOR_MEDIATEK is not set
CONFIG_NET_VENDOR_MELLANOX=y
CONFIG_MLX4_EN=m
CONFIG_MLX4_CORE=m
CONFIG_MLX4_DEBUG=y
CONFIG_MLX4_CORE_GEN2=y
CONFIG_MLX5_CORE=m
# CONFIG_MLX5_FPGA is not set
CONFIG_MLX5_CORE_EN=y
CONFIG_MLX5_EN_ARFS=y
CONFIG_MLX5_EN_RXNFC=y
CONFIG_MLX5_MPFS=y
CONFIG_MLX5_ESWITCH=y
# CONFIG_MLX5_CORE_IPOIB is not set
CONFIG_MLX5_SW_STEERING=y
# CONFIG_MLXSW_CORE is not set
# CONFIG_MLXFW is not set
CONFIG_NET_VENDOR_MICREL=y
# CONFIG_KS8842 is not set
# CONFIG_KS8851 is not set
# CONFIG_KS8851_MLL is not set
# CONFIG_KSZ884X_PCI is not set
CONFIG_NET_VENDOR_MICROCHIP=y
# CONFIG_ENC28J60 is not set
# CONFIG_ENCX24J600 is not set
# CONFIG_LAN743X is not set
CONFIG_NET_VENDOR_MICROSEMI=y
CONFIG_MSCC_OCELOT_SWITCH_LIB=m
CONFIG_MSCC_OCELOT_SWITCH=m
CONFIG_NET_VENDOR_MYRI=y
# CONFIG_MYRI10GE is not set
# CONFIG_FEALNX is not set
CONFIG_NET_VENDOR_NATSEMI=y
# CONFIG_NATSEMI is not set
# CONFIG_NS83820 is not set
CONFIG_NET_VENDOR_NETERION=y
# CONFIG_S2IO is not set
# CONFIG_VXGE is not set
CONFIG_NET_VENDOR_NETRONOME=y
# CONFIG_NFP is not set
CONFIG_NET_VENDOR_NI=y
# CONFIG_NI_XGE_MANAGEMENT_ENET is not set
CONFIG_NET_VENDOR_8390=y
# CONFIG_NE2K_PCI is not set
CONFIG_NET_VENDOR_NVIDIA=y
# CONFIG_FORCEDETH is not set
CONFIG_NET_VENDOR_OKI=y
# CONFIG_ETHOC is not set
CONFIG_NET_VENDOR_PACKET_ENGINES=y
# CONFIG_HAMACHI is not set
# CONFIG_YELLOWFIN is not set
CONFIG_NET_VENDOR_PENSANDO=y
# CONFIG_IONIC is not set
CONFIG_NET_VENDOR_QLOGIC=y
# CONFIG_QLA3XXX is not set
# CONFIG_QLCNIC is not set
# CONFIG_NETXEN_NIC is not set
# CONFIG_QED is not set
CONFIG_NET_VENDOR_QUALCOMM=y
# CONFIG_QCA7000_SPI is not set
# CONFIG_QCA7000_UART is not set
CONFIG_QCOM_EMAC=m
CONFIG_RMNET=m
CONFIG_NET_VENDOR_RDC=y
# CONFIG_R6040 is not set
CONFIG_NET_VENDOR_REALTEK=y
# CONFIG_8139CP is not set
# CONFIG_8139TOO is not set
# CONFIG_R8169 is not set
CONFIG_NET_VENDOR_RENESAS=y
# CONFIG_SH_ETH is not set
CONFIG_RAVB=y
CONFIG_NET_VENDOR_ROCKER=y
# CONFIG_ROCKER is not set
CONFIG_NET_VENDOR_SAMSUNG=y
# CONFIG_SXGBE_ETH is not set
CONFIG_NET_VENDOR_SEEQ=y
CONFIG_NET_VENDOR_SOLARFLARE=y
# CONFIG_SFC is not set
# CONFIG_SFC_FALCON is not set
CONFIG_NET_VENDOR_SILAN=y
# CONFIG_SC92031 is not set
CONFIG_NET_VENDOR_SIS=y
# CONFIG_SIS900 is not set
# CONFIG_SIS190 is not set
CONFIG_NET_VENDOR_SMSC=y
CONFIG_SMC91X=y
# CONFIG_EPIC100 is not set
CONFIG_SMSC911X=y
# CONFIG_SMSC9420 is not set
CONFIG_NET_VENDOR_SOCIONEXT=y
CONFIG_SNI_AVE=y
CONFIG_SNI_NETSEC=y
CONFIG_NET_VENDOR_STMICRO=y
CONFIG_STMMAC_ETH=m
# CONFIG_STMMAC_SELFTESTS is not set
CONFIG_STMMAC_PLATFORM=m
# CONFIG_DWMAC_DWC_QOS_ETH is not set
CONFIG_DWMAC_GENERIC=m
CONFIG_DWMAC_IPQ806X=m
# CONFIG_DWMAC_MEDIATEK is not set
CONFIG_DWMAC_MESON=m
CONFIG_DWMAC_QCOM_ETHQOS=m
CONFIG_DWMAC_ROCKCHIP=m
CONFIG_DWMAC_SOCFPGA=m
CONFIG_DWMAC_SUNXI=m
CONFIG_DWMAC_SUN8I=m
CONFIG_DWMAC_IMX8=m
# CONFIG_DWMAC_INTEL_PLAT is not set
# CONFIG_STMMAC_PCI is not set
CONFIG_NET_VENDOR_SUN=y
# CONFIG_HAPPYMEAL is not set
# CONFIG_SUNGEM is not set
# CONFIG_CASSINI is not set
# CONFIG_NIU is not set
CONFIG_NET_VENDOR_SYNOPSYS=y
# CONFIG_DWC_XLGMAC is not set
CONFIG_NET_VENDOR_TEHUTI=y
# CONFIG_TEHUTI is not set
CONFIG_NET_VENDOR_TI=y
CONFIG_TI_DAVINCI_MDIO=y
# CONFIG_TI_CPSW_PHY_SEL is not set
CONFIG_TI_K3_AM65_CPSW_NUSS=y
# CONFIG_TI_K3_AM65_CPTS is not set
# CONFIG_TLAN is not set
CONFIG_NET_VENDOR_VIA=y
# CONFIG_VIA_RHINE is not set
# CONFIG_VIA_VELOCITY is not set
CONFIG_NET_VENDOR_WIZNET=y
# CONFIG_WIZNET_W5100 is not set
# CONFIG_WIZNET_W5300 is not set
CONFIG_NET_VENDOR_XILINX=y
# CONFIG_XILINX_AXI_EMAC is not set
# CONFIG_XILINX_LL_TEMAC is not set
# CONFIG_FDDI is not set
# CONFIG_HIPPI is not set
CONFIG_QCOM_IPA=m
# CONFIG_NET_SB1000 is not set
CONFIG_PHYLINK=y
CONFIG_PHYLIB=y
CONFIG_SWPHY=y
# CONFIG_LED_TRIGGER_PHY is not set
CONFIG_FIXED_PHY=y
# CONFIG_SFP is not set

#
# MII PHY device drivers
#
# CONFIG_AMD_PHY is not set
CONFIG_MESON_GXL_PHY=m
# CONFIG_ADIN_PHY is not set
CONFIG_AQUANTIA_PHY=y
# CONFIG_AX88796B_PHY is not set
CONFIG_BROADCOM_PHY=m
# CONFIG_BCM54140_PHY is not set
CONFIG_BCM7XXX_PHY=m
# CONFIG_BCM84881_PHY is not set
# CONFIG_BCM87XX_PHY is not set
# CONFIG_BCM_CYGNUS_PHY is not set
CONFIG_BCM_NET_PHYLIB=m
# CONFIG_CICADA_PHY is not set
# CONFIG_CORTINA_PHY is not set
# CONFIG_DAVICOM_PHY is not set
# CONFIG_ICPLUS_PHY is not set
# CONFIG_LXT_PHY is not set
# CONFIG_INTEL_XWAY_PHY is not set
# CONFIG_LSI_ET1011C_PHY is not set
CONFIG_MARVELL_PHY=m
CONFIG_MARVELL_10G_PHY=m
CONFIG_MICREL_PHY=y
CONFIG_MICROCHIP_PHY=m
# CONFIG_MICROCHIP_T1_PHY is not set
CONFIG_MICROSEMI_PHY=y
# CONFIG_NATIONAL_PHY is not set
# CONFIG_NXP_TJA11XX_PHY is not set
CONFIG_AT803X_PHY=y
# CONFIG_QSEMI_PHY is not set
CONFIG_REALTEK_PHY=m
# CONFIG_RENESAS_PHY is not set
CONFIG_ROCKCHIP_PHY=y
CONFIG_SMSC_PHY=m
# CONFIG_STE10XP is not set
# CONFIG_TERANETICS_PHY is not set
# CONFIG_DP83822_PHY is not set
# CONFIG_DP83TC811_PHY is not set
# CONFIG_DP83848_PHY is not set
# CONFIG_DP83867_PHY is not set
# CONFIG_DP83869_PHY is not set
CONFIG_VITESSE_PHY=y
# CONFIG_XILINX_GMII2RGMII is not set
# CONFIG_MICREL_KS8995MA is not set
CONFIG_MDIO_DEVICE=y
CONFIG_MDIO_BUS=y
CONFIG_OF_MDIO=y
CONFIG_MDIO_DEVRES=y
# CONFIG_MDIO_SUN4I is not set
CONFIG_MDIO_XGENE=y
CONFIG_MDIO_BITBANG=y
CONFIG_MDIO_BCM_IPROC=y
CONFIG_MDIO_BCM_UNIMAC=m
CONFIG_MDIO_CAVIUM=y
# CONFIG_MDIO_GPIO is not set
# CONFIG_MDIO_HISI_FEMAC is not set
# CONFIG_MDIO_MVUSB is not set
# CONFIG_MDIO_MSCC_MIIM is not set
# CONFIG_MDIO_OCTEON is not set
# CONFIG_MDIO_IPQ4019 is not set
# CONFIG_MDIO_IPQ8064 is not set
CONFIG_MDIO_THUNDER=y

#
# MDIO Multiplexers
#
CONFIG_MDIO_BUS_MUX=y
CONFIG_MDIO_BUS_MUX_MESON_G12A=m
CONFIG_MDIO_BUS_MUX_BCM_IPROC=y
# CONFIG_MDIO_BUS_MUX_GPIO is not set
CONFIG_MDIO_BUS_MUX_MULTIPLEXER=y
CONFIG_MDIO_BUS_MUX_MMIOREG=y

#
# PCS device drivers
#
CONFIG_PCS_XPCS=m
CONFIG_PCS_LYNX=y

# end of PCS device drivers

# CONFIG_PPP is not set
# CONFIG_SLIP is not set
CONFIG_USB_NET_DRIVERS=y
# CONFIG_USB_CATC is not set
# CONFIG_USB_KAWETH is not set
CONFIG_USB_PEGASUS=m
CONFIG_USB_RTL8150=m
CONFIG_USB_RTL8152=m
CONFIG_USB_LAN78XX=m
CONFIG_USB_USBNET=m
CONFIG_USB_NET_AX8817X=m
CONFIG_USB_NET_AX88179_178A=m
CONFIG_USB_NET_CDCETHER=m
# CONFIG_USB_NET_CDC_EEM is not set
CONFIG_USB_NET_CDC_NCM=m
# CONFIG_USB_NET_HUAWEI_CDC_NCM is not set
# CONFIG_USB_NET_CDC_MBIM is not set
CONFIG_USB_NET_DM9601=m
# CONFIG_USB_NET_SR9700 is not set
CONFIG_USB_NET_SR9800=m
CONFIG_USB_NET_SMSC75XX=m
CONFIG_USB_NET_SMSC95XX=m
# CONFIG_USB_NET_GL620A is not set
CONFIG_USB_NET_NET1080=m
CONFIG_USB_NET_PLUSB=m
CONFIG_USB_NET_MCS7830=m
# CONFIG_USB_NET_RNDIS_HOST is not set
CONFIG_USB_NET_CDC_SUBSET_ENABLE=m
CONFIG_USB_NET_CDC_SUBSET=m
# CONFIG_USB_ALI_M5632 is not set
# CONFIG_USB_AN2720 is not set
CONFIG_USB_BELKIN=y
CONFIG_USB_ARMLINUX=y
# CONFIG_USB_EPSON2888 is not set
# CONFIG_USB_KC2190 is not set
CONFIG_USB_NET_ZAURUS=m
# CONFIG_USB_NET_CX82310_ETH is not set
# CONFIG_USB_NET_KALMIA is not set
# CONFIG_USB_NET_QMI_WWAN is not set
# CONFIG_USB_HSO is not set
# CONFIG_USB_NET_INT51X1 is not set
# CONFIG_USB_IPHETH is not set
# CONFIG_USB_SIERRA_NET is not set
# CONFIG_USB_VL600 is not set
# CONFIG_USB_NET_CH9200 is not set
# CONFIG_USB_NET_AQC111 is not set
CONFIG_WLAN=y
CONFIG_WLAN_VENDOR_ADMTEK=y
# CONFIG_ADM8211 is not set
CONFIG_ATH_COMMON=m
CONFIG_WLAN_VENDOR_ATH=y
# CONFIG_ATH_DEBUG is not set
# CONFIG_ATH5K is not set
# CONFIG_ATH5K_PCI is not set
# CONFIG_ATH9K is not set
# CONFIG_ATH9K_HTC is not set
# CONFIG_CARL9170 is not set
# CONFIG_ATH6KL is not set
# CONFIG_AR5523 is not set
# CONFIG_WIL6210 is not set
CONFIG_ATH10K=m
CONFIG_ATH10K_CE=y
CONFIG_ATH10K_PCI=m
# CONFIG_ATH10K_AHB is not set
# CONFIG_ATH10K_SDIO is not set
# CONFIG_ATH10K_USB is not set
CONFIG_ATH10K_SNOC=m
# CONFIG_ATH10K_DEBUG is not set
# CONFIG_ATH10K_DEBUGFS is not set
# CONFIG_ATH10K_TRACING is not set
# CONFIG_WCN36XX is not set
CONFIG_WLAN_VENDOR_ATMEL=y
# CONFIG_ATMEL is not set
# CONFIG_AT76C50X_USB is not set
CONFIG_WLAN_VENDOR_BROADCOM=y
# CONFIG_B43 is not set
# CONFIG_B43LEGACY is not set
CONFIG_BRCMUTIL=m
# CONFIG_BRCMSMAC is not set
CONFIG_BRCMFMAC=m
CONFIG_BRCMFMAC_PROTO_BCDC=y
CONFIG_BRCMFMAC_SDIO=y
# CONFIG_BRCMFMAC_USB is not set
# CONFIG_BRCMFMAC_PCIE is not set
# CONFIG_BRCM_TRACING is not set
# CONFIG_BRCMDBG is not set
CONFIG_WLAN_VENDOR_CISCO=y
CONFIG_WLAN_VENDOR_INTEL=y
# CONFIG_IPW2100 is not set
# CONFIG_IPW2200 is not set
# CONFIG_IWL4965 is not set
# CONFIG_IWL3945 is not set
# CONFIG_IWLWIFI is not set
CONFIG_WLAN_VENDOR_INTERSIL=y
# CONFIG_HOSTAP is not set
# CONFIG_HERMES is not set
# CONFIG_P54_COMMON is not set
# CONFIG_PRISM54 is not set
CONFIG_WLAN_VENDOR_MARVELL=y
# CONFIG_LIBERTAS is not set
# CONFIG_LIBERTAS_THINFIRM is not set
CONFIG_MWIFIEX=m
# CONFIG_MWIFIEX_SDIO is not set
CONFIG_MWIFIEX_PCIE=m
# CONFIG_MWIFIEX_USB is not set
# CONFIG_MWL8K is not set
CONFIG_WLAN_VENDOR_MEDIATEK=y
# CONFIG_MT7601U is not set
# CONFIG_MT76x0U is not set
# CONFIG_MT76x0E is not set
# CONFIG_MT76x2E is not set
# CONFIG_MT76x2U is not set
# CONFIG_MT7603E is not set
# CONFIG_MT7615E is not set
# CONFIG_MT7663U is not set
# CONFIG_MT7663S is not set
# CONFIG_MT7915E is not set
CONFIG_WLAN_VENDOR_MICROCHIP=y
# CONFIG_WILC1000_SDIO is not set
# CONFIG_WILC1000_SPI is not set
CONFIG_WLAN_VENDOR_RALINK=y
# CONFIG_RT2X00 is not set
CONFIG_WLAN_VENDOR_REALTEK=y
# CONFIG_RTL8180 is not set
# CONFIG_RTL8187 is not set
CONFIG_RTL_CARDS=m
# CONFIG_RTL8192CE is not set
# CONFIG_RTL8192SE is not set
# CONFIG_RTL8192DE is not set
# CONFIG_RTL8723AE is not set
# CONFIG_RTL8723BE is not set
# CONFIG_RTL8188EE is not set
# CONFIG_RTL8192EE is not set
# CONFIG_RTL8821AE is not set
# CONFIG_RTL8192CU is not set
# CONFIG_RTL8XXXU is not set
# CONFIG_RTW88 is not set
CONFIG_WLAN_VENDOR_RSI=y
# CONFIG_RSI_91X is not set
CONFIG_WLAN_VENDOR_ST=y
# CONFIG_CW1200 is not set
CONFIG_WLAN_VENDOR_TI=y
# CONFIG_WL1251 is not set
# CONFIG_WL12XX is not set
CONFIG_WL18XX=m
CONFIG_WLCORE=m
# CONFIG_WLCORE_SPI is not set
CONFIG_WLCORE_SDIO=m
CONFIG_WILINK_PLATFORM_DATA=y
CONFIG_WLAN_VENDOR_ZYDAS=y
# CONFIG_USB_ZD1201 is not set
# CONFIG_ZD1211RW is not set
CONFIG_WLAN_VENDOR_QUANTENNA=y
# CONFIG_QTNFMAC_PCIE is not set
# CONFIG_MAC80211_HWSIM is not set
# CONFIG_USB_NET_RNDIS_WLAN is not set
# CONFIG_VIRT_WIFI is not set
# CONFIG_WAN is not set
CONFIG_XEN_NETDEV_FRONTEND=y
# CONFIG_XEN_NETDEV_BACKEND is not set
# CONFIG_VMXNET3 is not set
# CONFIG_FUJITSU_ES is not set
# CONFIG_NETDEVSIM is not set
CONFIG_NET_FAILOVER=y
# CONFIG_ISDN is not set
# CONFIG_NVM is not set

#
# Input device support
#
CONFIG_INPUT=y
CONFIG_INPUT_LEDS=y
CONFIG_INPUT_FF_MEMLESS=y
# CONFIG_INPUT_POLLDEV is not set
# CONFIG_INPUT_SPARSEKMAP is not set
CONFIG_INPUT_MATRIXKMAP=y

#
# Userland interfaces
#
# CONFIG_INPUT_MOUSEDEV is not set
# CONFIG_INPUT_JOYDEV is not set
CONFIG_INPUT_EVDEV=y
# CONFIG_INPUT_EVBUG is not set

#
# Input Device Drivers
#
CONFIG_INPUT_KEYBOARD=y
CONFIG_KEYBOARD_ADC=m
# CONFIG_KEYBOARD_ADP5588 is not set
# CONFIG_KEYBOARD_ADP5589 is not set
CONFIG_KEYBOARD_ATKBD=y
# CONFIG_KEYBOARD_QT1050 is not set
# CONFIG_KEYBOARD_QT1070 is not set
# CONFIG_KEYBOARD_QT2160 is not set
# CONFIG_KEYBOARD_DLINK_DIR685 is not set
# CONFIG_KEYBOARD_LKKBD is not set
CONFIG_KEYBOARD_GPIO=y
# CONFIG_KEYBOARD_GPIO_POLLED is not set
# CONFIG_KEYBOARD_TCA6416 is not set
# CONFIG_KEYBOARD_TCA8418 is not set
# CONFIG_KEYBOARD_MATRIX is not set
# CONFIG_KEYBOARD_LM8323 is not set
# CONFIG_KEYBOARD_LM8333 is not set
# CONFIG_KEYBOARD_MAX7359 is not set
# CONFIG_KEYBOARD_MCS is not set
# CONFIG_KEYBOARD_MPR121 is not set
CONFIG_KEYBOARD_SNVS_PWRKEY=m
# CONFIG_KEYBOARD_IMX is not set
CONFIG_KEYBOARD_IMX_SC_KEY=m
# CONFIG_KEYBOARD_NEWTON is not set
# CONFIG_KEYBOARD_TEGRA is not set
# CONFIG_KEYBOARD_OPENCORES is not set
# CONFIG_KEYBOARD_SAMSUNG is not set
# CONFIG_KEYBOARD_STOWAWAY is not set
# CONFIG_KEYBOARD_SUNKBD is not set
# CONFIG_KEYBOARD_SUN4I_LRADC is not set
# CONFIG_KEYBOARD_OMAP4 is not set
# CONFIG_KEYBOARD_TM2_TOUCHKEY is not set
# CONFIG_KEYBOARD_XTKBD is not set
CONFIG_KEYBOARD_CROS_EC=y
# CONFIG_KEYBOARD_CAP11XX is not set
# CONFIG_KEYBOARD_BCM is not set
CONFIG_INPUT_MOUSE=y
CONFIG_MOUSE_PS2=y
CONFIG_MOUSE_PS2_ALPS=y
CONFIG_MOUSE_PS2_BYD=y
CONFIG_MOUSE_PS2_LOGIPS2PP=y
CONFIG_MOUSE_PS2_SYNAPTICS=y
CONFIG_MOUSE_PS2_SYNAPTICS_SMBUS=y
CONFIG_MOUSE_PS2_CYPRESS=y
CONFIG_MOUSE_PS2_TRACKPOINT=y
# CONFIG_MOUSE_PS2_ELANTECH is not set
# CONFIG_MOUSE_PS2_SENTELIC is not set
# CONFIG_MOUSE_PS2_TOUCHKIT is not set
CONFIG_MOUSE_PS2_FOCALTECH=y
CONFIG_MOUSE_PS2_SMBUS=y
# CONFIG_MOUSE_SERIAL is not set
# CONFIG_MOUSE_APPLETOUCH is not set
# CONFIG_MOUSE_BCM5974 is not set
# CONFIG_MOUSE_CYAPA is not set
# CONFIG_MOUSE_ELAN_I2C is not set
# CONFIG_MOUSE_VSXXXAA is not set
# CONFIG_MOUSE_GPIO is not set
# CONFIG_MOUSE_SYNAPTICS_I2C is not set
# CONFIG_MOUSE_SYNAPTICS_USB is not set
# CONFIG_INPUT_JOYSTICK is not set
# CONFIG_INPUT_TABLET is not set
CONFIG_INPUT_TOUCHSCREEN=y
CONFIG_TOUCHSCREEN_PROPERTIES=y
# CONFIG_TOUCHSCREEN_ADS7846 is not set
# CONFIG_TOUCHSCREEN_AD7877 is not set
# CONFIG_TOUCHSCREEN_AD7879 is not set
# CONFIG_TOUCHSCREEN_ADC is not set
# CONFIG_TOUCHSCREEN_AR1021_I2C is not set
CONFIG_TOUCHSCREEN_ATMEL_MXT=m
# CONFIG_TOUCHSCREEN_ATMEL_MXT_T37 is not set
# CONFIG_TOUCHSCREEN_AUO_PIXCIR is not set
# CONFIG_TOUCHSCREEN_BU21013 is not set
# CONFIG_TOUCHSCREEN_BU21029 is not set
# CONFIG_TOUCHSCREEN_CHIPONE_ICN8318 is not set
# CONFIG_TOUCHSCREEN_CHIPONE_ICN8505 is not set
# CONFIG_TOUCHSCREEN_CY8CTMA140 is not set
# CONFIG_TOUCHSCREEN_CY8CTMG110 is not set
# CONFIG_TOUCHSCREEN_CYTTSP_CORE is not set
# CONFIG_TOUCHSCREEN_CYTTSP4_CORE is not set
# CONFIG_TOUCHSCREEN_DYNAPRO is not set
# CONFIG_TOUCHSCREEN_HAMPSHIRE is not set
# CONFIG_TOUCHSCREEN_EETI is not set
# CONFIG_TOUCHSCREEN_EGALAX is not set
# CONFIG_TOUCHSCREEN_EGALAX_SERIAL is not set
# CONFIG_TOUCHSCREEN_EXC3000 is not set
# CONFIG_TOUCHSCREEN_FUJITSU is not set
# CONFIG_TOUCHSCREEN_GOODIX is not set
# CONFIG_TOUCHSCREEN_HIDEEP is not set
# CONFIG_TOUCHSCREEN_ILI210X is not set
# CONFIG_TOUCHSCREEN_IPROC is not set
# CONFIG_TOUCHSCREEN_S6SY761 is not set
# CONFIG_TOUCHSCREEN_GUNZE is not set
# CONFIG_TOUCHSCREEN_EKTF2127 is not set
# CONFIG_TOUCHSCREEN_ELAN is not set
# CONFIG_TOUCHSCREEN_ELO is not set
# CONFIG_TOUCHSCREEN_WACOM_W8001 is not set
# CONFIG_TOUCHSCREEN_WACOM_I2C is not set
# CONFIG_TOUCHSCREEN_MAX11801 is not set
# CONFIG_TOUCHSCREEN_MCS5000 is not set
# CONFIG_TOUCHSCREEN_MMS114 is not set
# CONFIG_TOUCHSCREEN_MELFAS_MIP4 is not set
# CONFIG_TOUCHSCREEN_MTOUCH is not set
# CONFIG_TOUCHSCREEN_IMX6UL_TSC is not set
# CONFIG_TOUCHSCREEN_INEXIO is not set
# CONFIG_TOUCHSCREEN_MK712 is not set
# CONFIG_TOUCHSCREEN_PENMOUNT is not set
# CONFIG_TOUCHSCREEN_EDT_FT5X06 is not set
# CONFIG_TOUCHSCREEN_RASPBERRYPI_FW is not set
# CONFIG_TOUCHSCREEN_TOUCHRIGHT is not set
# CONFIG_TOUCHSCREEN_TOUCHWIN is not set
# CONFIG_TOUCHSCREEN_PIXCIR is not set
# CONFIG_TOUCHSCREEN_WDT87XX_I2C is not set
# CONFIG_TOUCHSCREEN_USB_COMPOSITE is not set
# CONFIG_TOUCHSCREEN_TOUCHIT213 is not set
# CONFIG_TOUCHSCREEN_TSC_SERIO is not set
# CONFIG_TOUCHSCREEN_TSC2004 is not set
# CONFIG_TOUCHSCREEN_TSC2005 is not set
# CONFIG_TOUCHSCREEN_TSC2007 is not set
# CONFIG_TOUCHSCREEN_RM_TS is not set
# CONFIG_TOUCHSCREEN_SILEAD is not set
# CONFIG_TOUCHSCREEN_SIS_I2C is not set
# CONFIG_TOUCHSCREEN_ST1232 is not set
# CONFIG_TOUCHSCREEN_STMFTS is not set
# CONFIG_TOUCHSCREEN_SUN4I is not set
# CONFIG_TOUCHSCREEN_SUR40 is not set
# CONFIG_TOUCHSCREEN_SURFACE3_SPI is not set
# CONFIG_TOUCHSCREEN_SX8654 is not set
# CONFIG_TOUCHSCREEN_TPS6507X is not set
# CONFIG_TOUCHSCREEN_ZET6223 is not set
# CONFIG_TOUCHSCREEN_ZFORCE is not set
# CONFIG_TOUCHSCREEN_ROHM_BU21023 is not set
# CONFIG_TOUCHSCREEN_IQS5XX is not set
# CONFIG_TOUCHSCREEN_ZINITIX is not set
CONFIG_INPUT_MISC=y
# CONFIG_INPUT_AD714X is not set
# CONFIG_INPUT_ATMEL_CAPTOUCH is not set
# CONFIG_INPUT_BMA150 is not set
# CONFIG_INPUT_E3X0_BUTTON is not set
CONFIG_INPUT_PM8941_PWRKEY=y
CONFIG_INPUT_PM8XXX_VIBRATOR=m
# CONFIG_INPUT_MMA8450 is not set
# CONFIG_INPUT_GPIO_BEEPER is not set
# CONFIG_INPUT_GPIO_DECODER is not set
# CONFIG_INPUT_GPIO_VIBRA is not set
# CONFIG_INPUT_ATI_REMOTE2 is not set
# CONFIG_INPUT_KEYSPAN_REMOTE is not set
# CONFIG_INPUT_KXTJ9 is not set
# CONFIG_INPUT_POWERMATE is not set
# CONFIG_INPUT_YEALINK is not set
# CONFIG_INPUT_CM109 is not set
# CONFIG_INPUT_REGULATOR_HAPTIC is not set
# CONFIG_INPUT_AXP20X_PEK is not set
# CONFIG_INPUT_UINPUT is not set
# CONFIG_INPUT_PCF8574 is not set
# CONFIG_INPUT_PWM_BEEPER is not set
# CONFIG_INPUT_PWM_VIBRA is not set
# CONFIG_INPUT_RK805_PWRKEY is not set
# CONFIG_INPUT_GPIO_ROTARY_ENCODER is not set
# CONFIG_INPUT_ADXL34X is not set
# CONFIG_INPUT_IMS_PCU is not set
# CONFIG_INPUT_IQS269A is not set
# CONFIG_INPUT_CMA3000 is not set
CONFIG_INPUT_XEN_KBDDEV_FRONTEND=y
# CONFIG_INPUT_SOC_BUTTON_ARRAY is not set
# CONFIG_INPUT_DRV260X_HAPTICS is not set
# CONFIG_INPUT_DRV2665_HAPTICS is not set
# CONFIG_INPUT_DRV2667_HAPTICS is not set
CONFIG_INPUT_HISI_POWERKEY=y
# CONFIG_RMI4_CORE is not set

#
# Hardware I/O ports
#
CONFIG_SERIO=y
# CONFIG_SERIO_SERPORT is not set
CONFIG_SERIO_AMBAKMI=y
# CONFIG_SERIO_PCIPS2 is not set
CONFIG_SERIO_LIBPS2=y
# CONFIG_SERIO_RAW is not set
# CONFIG_SERIO_ALTERA_PS2 is not set
# CONFIG_SERIO_PS2MULT is not set
# CONFIG_SERIO_ARC_PS2 is not set
# CONFIG_SERIO_APBPS2 is not set
# CONFIG_SERIO_SUN4I_PS2 is not set
# CONFIG_SERIO_GPIO_PS2 is not set
# CONFIG_USERIO is not set
# CONFIG_GAMEPORT is not set

# end of Hardware I/O ports
# end of Input device support

#
# Character devices
#
CONFIG_TTY=y
CONFIG_VT=y
CONFIG_CONSOLE_TRANSLATIONS=y
CONFIG_VT_CONSOLE=y
CONFIG_VT_CONSOLE_SLEEP=y
CONFIG_HW_CONSOLE=y
CONFIG_VT_HW_CONSOLE_BINDING=y
CONFIG_UNIX98_PTYS=y
CONFIG_LEGACY_PTYS=y
CONFIG_LEGACY_PTY_COUNT=16
CONFIG_LDISC_AUTOLOAD=y

#
# Serial drivers
#
CONFIG_SERIAL_EARLYCON=y
CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_DEPRECATED_OPTIONS=y
CONFIG_SERIAL_8250_PNP=y
CONFIG_SERIAL_8250_16550A_VARIANTS=y
# CONFIG_SERIAL_8250_FINTEK is not set
CONFIG_SERIAL_8250_CONSOLE=y
CONFIG_SERIAL_8250_DMA=y
CONFIG_SERIAL_8250_PCI=y
CONFIG_SERIAL_8250_EXAR=y
CONFIG_SERIAL_8250_NR_UARTS=4
CONFIG_SERIAL_8250_RUNTIME_UARTS=4
CONFIG_SERIAL_8250_EXTENDED=y
# CONFIG_SERIAL_8250_MANY_PORTS is not set
# CONFIG_SERIAL_8250_ASPEED_VUART is not set
CONFIG_SERIAL_8250_SHARE_IRQ=y
# CONFIG_SERIAL_8250_DETECT_IRQ is not set
# CONFIG_SERIAL_8250_RSA is not set
CONFIG_SERIAL_8250_DWLIB=y
CONFIG_SERIAL_8250_BCM2835AUX=y
CONFIG_SERIAL_8250_FSL=y
CONFIG_SERIAL_8250_DW=y
# CONFIG_SERIAL_8250_RT288X is not set
CONFIG_SERIAL_8250_OMAP=y
CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP=y
CONFIG_SERIAL_8250_MT6577=y
CONFIG_SERIAL_8250_UNIPHIER=y
CONFIG_SERIAL_8250_TEGRA=y
CONFIG_SERIAL_OF_PLATFORM=y

#
# Non-8250 serial port support
#
# CONFIG_SERIAL_AMBA_PL010 is not set
CONFIG_SERIAL_AMBA_PL011=y
CONFIG_SERIAL_AMBA_PL011_CONSOLE=y
# CONFIG_SERIAL_EARLYCON_ARM_SEMIHOST is not set
CONFIG_SERIAL_MESON=y
CONFIG_SERIAL_MESON_CONSOLE=y
CONFIG_SERIAL_SAMSUNG=y
CONFIG_SERIAL_SAMSUNG_UARTS_4=y
CONFIG_SERIAL_SAMSUNG_UARTS=4
CONFIG_SERIAL_SAMSUNG_CONSOLE=y
CONFIG_SERIAL_TEGRA=y
CONFIG_SERIAL_TEGRA_TCU=y
CONFIG_SERIAL_TEGRA_TCU_CONSOLE=y
# CONFIG_SERIAL_MAX3100 is not set
# CONFIG_SERIAL_MAX310X is not set
CONFIG_SERIAL_IMX=y
CONFIG_SERIAL_IMX_CONSOLE=y
# CONFIG_SERIAL_IMX_EARLYCON is not set
# CONFIG_SERIAL_UARTLITE is not set
CONFIG_SERIAL_SH_SCI=y
CONFIG_SERIAL_SH_SCI_NR_UARTS=18
CONFIG_SERIAL_SH_SCI_CONSOLE=y
CONFIG_SERIAL_SH_SCI_EARLYCON=y
CONFIG_SERIAL_SH_SCI_DMA=y
CONFIG_SERIAL_CORE=y
CONFIG_SERIAL_CORE_CONSOLE=y
# CONFIG_SERIAL_JSM is not set
CONFIG_SERIAL_MSM=y
CONFIG_SERIAL_MSM_CONSOLE=y
CONFIG_SERIAL_QCOM_GENI=y
CONFIG_SERIAL_QCOM_GENI_CONSOLE=y
# CONFIG_SERIAL_SIFIVE is not set
# CONFIG_SERIAL_SCCNXP is not set
# CONFIG_SERIAL_SC16IS7XX is not set
# CONFIG_SERIAL_ALTERA_JTAGUART is not set
# CONFIG_SERIAL_ALTERA_UART is not set
# CONFIG_SERIAL_IFX6X60 is not set
CONFIG_SERIAL_XILINX_PS_UART=y
CONFIG_SERIAL_XILINX_PS_UART_CONSOLE=y
# CONFIG_SERIAL_ARC is not set
# CONFIG_SERIAL_RP2 is not set
CONFIG_SERIAL_FSL_LPUART=y
CONFIG_SERIAL_FSL_LPUART_CONSOLE=y
CONFIG_SERIAL_FSL_LINFLEXUART=y
CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE=y
# CONFIG_SERIAL_CONEXANT_DIGICOLOR is not set
# CONFIG_SERIAL_SPRD is not set
CONFIG_SERIAL_MVEBU_UART=y
CONFIG_SERIAL_MVEBU_CONSOLE=y
CONFIG_SERIAL_OWL=y
CONFIG_SERIAL_OWL_CONSOLE=y

# end of Serial drivers

CONFIG_SERIAL_MCTRL_GPIO=y
# CONFIG_SERIAL_NONSTANDARD is not set
# CONFIG_N_GSM is not set
# CONFIG_NOZOMI is not set
# CONFIG_NULL_TTY is not set
CONFIG_TRACE_ROUTER=m
CONFIG_TRACE_SINK=m
CONFIG_HVC_DRIVER=y
CONFIG_HVC_IRQ=y
CONFIG_HVC_XEN=y
CONFIG_HVC_XEN_FRONTEND=y
# CONFIG_HVC_DCC is not set
CONFIG_SERIAL_DEV_BUS=y
CONFIG_SERIAL_DEV_CTRL_TTYPORT=y
CONFIG_VIRTIO_CONSOLE=y
CONFIG_IPMI_HANDLER=m
CONFIG_IPMI_DMI_DECODE=y
CONFIG_IPMI_PLAT_DATA=y
# CONFIG_IPMI_PANIC_EVENT is not set
CONFIG_IPMI_DEVICE_INTERFACE=m
CONFIG_IPMI_SI=m
# CONFIG_IPMI_SSIF is not set
CONFIG_IPMI_WATCHDOG=m
# CONFIG_IPMI_POWEROFF is not set
# CONFIG_IPMB_DEVICE_INTERFACE is not set
CONFIG_HW_RANDOM=m
# CONFIG_HW_RANDOM_TIMERIOMEM is not set
# CONFIG_HW_RANDOM_BA431 is not set
CONFIG_HW_RANDOM_BCM2835=m
CONFIG_HW_RANDOM_IPROC_RNG200=m
CONFIG_HW_RANDOM_OMAP=m
# CONFIG_HW_RANDOM_VIRTIO is not set
CONFIG_HW_RANDOM_HISI=m
CONFIG_HW_RANDOM_HISI_V2=m
CONFIG_HW_RANDOM_XGENE=m
CONFIG_HW_RANDOM_MESON=m
CONFIG_HW_RANDOM_CAVIUM=m
CONFIG_HW_RANDOM_MTK=m
CONFIG_HW_RANDOM_EXYNOS=m
CONFIG_HW_RANDOM_OPTEE=m
# CONFIG_HW_RANDOM_CCTRNG is not set
# CONFIG_HW_RANDOM_XIPHERA is not set
# CONFIG_APPLICOM is not set
CONFIG_DEVMEM=y
# CONFIG_RAW_DRIVER is not set
CONFIG_DEVPORT=y
CONFIG_TCG_TPM=y
# CONFIG_TCG_TIS is not set
# CONFIG_TCG_TIS_SPI is not set
# CONFIG_TCG_TIS_SYNQUACER is not set
# CONFIG_TCG_TIS_I2C_ATMEL is not set
CONFIG_TCG_TIS_I2C_INFINEON=y
# CONFIG_TCG_TIS_I2C_NUVOTON is not set
# CONFIG_TCG_ATMEL is not set
# CONFIG_TCG_INFINEON is not set
# CONFIG_TCG_XEN is not set
# CONFIG_TCG_CRB is not set
# CONFIG_TCG_VTPM_PROXY is not set
# CONFIG_TCG_FTPM_TEE is not set
# CONFIG_TCG_TIS_ST33ZP24_I2C is not set
# CONFIG_TCG_TIS_ST33ZP24_SPI is not set
# CONFIG_XILLYBUS is not set

# end of Character devices

# CONFIG_RANDOM_TRUST_CPU is not set
# CONFIG_RANDOM_TRUST_BOOTLOADER is not set

#
# I2C support
#
CONFIG_I2C=y
CONFIG_ACPI_I2C_OPREGION=y
CONFIG_I2C_BOARDINFO=y
CONFIG_I2C_COMPAT=y
CONFIG_I2C_CHARDEV=y
CONFIG_I2C_MUX=y

#
# Multiplexer I2C Chip support
#
# CONFIG_I2C_ARB_GPIO_CHALLENGE is not set
# CONFIG_I2C_MUX_GPIO is not set
# CONFIG_I2C_MUX_GPMUX is not set
# CONFIG_I2C_MUX_LTC4306 is not set
# CONFIG_I2C_MUX_PCA9541 is not set
CONFIG_I2C_MUX_PCA954x=y
# CONFIG_I2C_MUX_PINCTRL is not set
# CONFIG_I2C_MUX_REG is not set
# CONFIG_I2C_DEMUX_PINCTRL is not set
# CONFIG_I2C_MUX_MLXCPLD is not set

# end of Multiplexer I2C Chip support

CONFIG_I2C_HELPER_AUTO=y
CONFIG_I2C_SMBUS=y
CONFIG_I2C_ALGOBIT=y

#
# I2C Hardware Bus support
#

#
# PC SMBus host controller drivers
#
# CONFIG_I2C_ALI1535 is not set
# CONFIG_I2C_ALI1563 is not set
# CONFIG_I2C_ALI15X3 is not set
# CONFIG_I2C_AMD756 is not set
# CONFIG_I2C_AMD8111 is not set
# CONFIG_I2C_AMD_MP2 is not set
# CONFIG_I2C_HIX5HD2 is not set
# CONFIG_I2C_I801 is not set
# CONFIG_I2C_ISCH is not set
# CONFIG_I2C_PIIX4 is not set
# CONFIG_I2C_NFORCE2 is not set
# CONFIG_I2C_NVIDIA_GPU is not set
# CONFIG_I2C_SIS5595 is not set
# CONFIG_I2C_SIS630 is not set
# CONFIG_I2C_SIS96X is not set
# CONFIG_I2C_VIA is not set
# CONFIG_I2C_VIAPRO is not set

#
# ACPI drivers
#
# CONFIG_I2C_SCMI is not set

#
# I2C system bus drivers (mostly embedded / system-on-chip) #
CONFIG_I2C_BCM2835=m
CONFIG_I2C_BCM_IPROC=y
CONFIG_I2C_BRCMSTB=y
# CONFIG_I2C_CADENCE is not set
# CONFIG_I2C_CBUS_GPIO is not set CONFIG_I2C_DESIGNWARE_CORE=y
# CONFIG_I2C_DESIGNWARE_SLAVE is not set CONFIG_I2C_DESIGNWARE_PLATFORM=y
# CONFIG_I2C_DESIGNWARE_PCI is not set
# CONFIG_I2C_EMEV2 is not set
CONFIG_I2C_EXYNOS5=y
CONFIG_I2C_GPIO=m
# CONFIG_I2C_GPIO_FAULT_INJECTOR is not set CONFIG_I2C_IMX=y
CONFIG_I2C_IMX_LPI2C=y
CONFIG_I2C_MESON=y
# CONFIG_I2C_MT65XX is not set CONFIG_I2C_MV64XXX=y
# CONFIG_I2C_NOMADIK is not set
# CONFIG_I2C_OCORES is not set
# CONFIG_I2C_OMAP is not set
CONFIG_I2C_OWL=y
# CONFIG_I2C_PCA_PLATFORM is not set CONFIG_I2C_PXA=y
# CONFIG_I2C_PXA_SLAVE is not set CONFIG_I2C_QCOM_CCI=m
CONFIG_I2C_QCOM_GENI=m
CONFIG_I2C_QUP=y
# CONFIG_I2C_RIIC is not set
CONFIG_I2C_RK3X=y
CONFIG_I2C_SH_MOBILE=y
# CONFIG_I2C_SIMTEC is not set
# CONFIG_I2C_SPRD is not set
# CONFIG_I2C_SYNQUACER is not set CONFIG_I2C_TEGRA=y
CONFIG_I2C_TEGRA_BPMP=y
# CONFIG_I2C_UNIPHIER is not set CONFIG_I2C_UNIPHIER_F=y
# CONFIG_I2C_VERSATILE is not set
# CONFIG_I2C_THUNDERX is not set
# CONFIG_I2C_XILINX is not set
# CONFIG_I2C_XLP9XX is not set
CONFIG_I2C_RCAR=y

#
# External I2C/SMBus adapter drivers
#
# CONFIG_I2C_DIOLAN_U2C is not set
# CONFIG_I2C_ROBOTFUZZ_OSIF is not set
# CONFIG_I2C_TAOS_EVM is not set
# CONFIG_I2C_TINY_USB is not set

#
# Other I2C/SMBus bus drivers
#
CONFIG_I2C_CROS_EC_TUNNEL=y
# CONFIG_I2C_XGENE_SLIMPRO is not set
CONFIG_I2C_ZX2967=y

# end of I2C Hardware Bus support

# CONFIG_I2C_STUB is not set
CONFIG_I2C_SLAVE=y
# CONFIG_I2C_SLAVE_EEPROM is not set
# CONFIG_I2C_SLAVE_TESTUNIT is not set
# CONFIG_I2C_DEBUG_CORE is not set
# CONFIG_I2C_DEBUG_ALGO is not set
# CONFIG_I2C_DEBUG_BUS is not set

# end of I2C support

# CONFIG_I3C is not set
CONFIG_SPI=y
# CONFIG_SPI_DEBUG is not set
CONFIG_SPI_MASTER=y
CONFIG_SPI_MEM=y

#
# SPI Master Controller Drivers
#
# CONFIG_SPI_ALTERA is not set
CONFIG_SPI_ARMADA_3700=y
# CONFIG_SPI_AXI_SPI_ENGINE is not set
CONFIG_SPI_BCM2835=m
CONFIG_SPI_BCM2835AUX=m
CONFIG_SPI_BCM_QSPI=y
CONFIG_SPI_BITBANG=m
# CONFIG_SPI_CADENCE is not set
CONFIG_SPI_CADENCE_QUADSPI=y
# CONFIG_SPI_DESIGNWARE is not set
CONFIG_SPI_FSL_LPSPI=y
CONFIG_SPI_FSL_QUADSPI=y
# CONFIG_SPI_HISI_SFC_V3XX is not set
CONFIG_SPI_NXP_FLEXSPI=y
# CONFIG_SPI_GPIO is not set
CONFIG_SPI_IMX=m
# CONFIG_SPI_FSL_SPI is not set
CONFIG_SPI_FSL_DSPI=y
CONFIG_SPI_MESON_SPICC=m
CONFIG_SPI_MESON_SPIFC=m
# CONFIG_SPI_MT65XX is not set
# CONFIG_SPI_MTK_NOR is not set
# CONFIG_SPI_OC_TINY is not set
# CONFIG_SPI_OMAP24XX is not set
CONFIG_SPI_ORION=y
CONFIG_SPI_PL022=y
# CONFIG_SPI_PXA2XX is not set
CONFIG_SPI_ROCKCHIP=y
# CONFIG_SPI_RSPI is not set
CONFIG_SPI_QCOM_QSPI=m
CONFIG_SPI_QUP=y
CONFIG_SPI_QCOM_GENI=m
CONFIG_SPI_S3C64XX=y
# CONFIG_SPI_SC18IS602 is not set
CONFIG_SPI_SH_MSIOF=m
# CONFIG_SPI_SH_HSPI is not set
# CONFIG_SPI_SIFIVE is not set
# CONFIG_SPI_SPRD is not set
# CONFIG_SPI_SPRD_ADI is not set
# CONFIG_SPI_SUN4I is not set
CONFIG_SPI_SUN6I=y
# CONFIG_SPI_SYNQUACER is not set
# CONFIG_SPI_MXIC is not set
# CONFIG_SPI_TEGRA114 is not set
# CONFIG_SPI_TEGRA20_SFLASH is not set
# CONFIG_SPI_TEGRA20_SLINK is not set
# CONFIG_SPI_THUNDERX is not set
# CONFIG_SPI_UNIPHIER is not set
# CONFIG_SPI_XCOMM is not set
# CONFIG_SPI_XILINX is not set
# CONFIG_SPI_XLP is not set
# CONFIG_SPI_ZYNQMP_GQSPI is not set
# CONFIG_SPI_AMD is not set

#
# SPI Multiplexer support
#
# CONFIG_SPI_MUX is not set

#
# SPI Protocol Masters
#
CONFIG_SPI_SPIDEV=m
# CONFIG_SPI_LOOPBACK_TEST is not set
# CONFIG_SPI_TLE62X0 is not set
# CONFIG_SPI_SLAVE is not set
CONFIG_SPI_DYNAMIC=y
CONFIG_SPMI=y
CONFIG_SPMI_MSM_PMIC_ARB=y
# CONFIG_HSI is not set
CONFIG_PPS=y
# CONFIG_PPS_DEBUG is not set

#
# PPS clients support
#
# CONFIG_PPS_CLIENT_KTIMER is not set
# CONFIG_PPS_CLIENT_LDISC is not set
# CONFIG_PPS_CLIENT_GPIO is not set

#
# PPS generators support
#

#
# PTP clock support
#
CONFIG_PTP_1588_CLOCK=y
CONFIG_PTP_1588_CLOCK_DTE=y
CONFIG_PTP_1588_CLOCK_QORIQ=y

#
# Enable PHYLIB and NETWORK_PHY_TIMESTAMPING to see the additional clocks. #
# CONFIG_PTP_1588_CLOCK_IDT82P33 is not set
# CONFIG_PTP_1588_CLOCK_IDTCM is not set

# end of PTP clock support

CONFIG_PINCTRL=y
CONFIG_GENERIC_PINCTRL_GROUPS=y
CONFIG_PINMUX=y
CONFIG_GENERIC_PINMUX_FUNCTIONS=y
CONFIG_PINCONF=y
CONFIG_GENERIC_PINCONF=y
# CONFIG_DEBUG_PINCTRL is not set
# CONFIG_PINCTRL_AXP209 is not set
# CONFIG_PINCTRL_AMD is not set
# CONFIG_PINCTRL_MCP23S08 is not set
CONFIG_PINCTRL_ROCKCHIP=y
CONFIG_PINCTRL_SINGLE=y
# CONFIG_PINCTRL_SX150X is not set
# CONFIG_PINCTRL_STMFX is not set
CONFIG_PINCTRL_MAX77620=y
# CONFIG_PINCTRL_RK805 is not set
# CONFIG_PINCTRL_OCELOT is not set
CONFIG_PINCTRL_OWL=y
# CONFIG_PINCTRL_S500 is not set
CONFIG_PINCTRL_S700=y
CONFIG_PINCTRL_S900=y
CONFIG_PINCTRL_BCM2835=y
CONFIG_PINCTRL_IPROC_GPIO=y
CONFIG_PINCTRL_NS2_MUX=y
# CONFIG_PINCTRL_AS370 is not set
# CONFIG_PINCTRL_BERLIN_BG4CT is not set
CONFIG_PINCTRL_IMX=y
CONFIG_PINCTRL_IMX_SCU=y
CONFIG_PINCTRL_IMX8MM=y
CONFIG_PINCTRL_IMX8MN=y
CONFIG_PINCTRL_IMX8MP=y
CONFIG_PINCTRL_IMX8MQ=y
# CONFIG_PINCTRL_IMX8QM is not set
CONFIG_PINCTRL_IMX8QXP=y
CONFIG_PINCTRL_IMX8DXL=y
CONFIG_PINCTRL_MVEBU=y
CONFIG_PINCTRL_ARMADA_AP806=y
CONFIG_PINCTRL_ARMADA_CP110=y
CONFIG_PINCTRL_ARMADA_37XX=y
CONFIG_PINCTRL_MSM=y
# CONFIG_PINCTRL_APQ8064 is not set
# CONFIG_PINCTRL_APQ8084 is not set
# CONFIG_PINCTRL_IPQ4019 is not set
# CONFIG_PINCTRL_IPQ8064 is not set
CONFIG_PINCTRL_IPQ8074=y
CONFIG_PINCTRL_IPQ6018=y
# CONFIG_PINCTRL_MSM8226 is not set
# CONFIG_PINCTRL_MSM8660 is not set
# CONFIG_PINCTRL_MSM8960 is not set
# CONFIG_PINCTRL_MDM9615 is not set
# CONFIG_PINCTRL_MSM8X74 is not set
CONFIG_PINCTRL_MSM8916=y
# CONFIG_PINCTRL_MSM8953 is not set
# CONFIG_PINCTRL_MSM8976 is not set
CONFIG_PINCTRL_MSM8994=y
CONFIG_PINCTRL_MSM8996=y
CONFIG_PINCTRL_MSM8998=y
CONFIG_PINCTRL_QCS404=y
CONFIG_PINCTRL_QDF2XXX=y
CONFIG_PINCTRL_QCOM_SPMI_PMIC=y
# CONFIG_PINCTRL_QCOM_SSBI_PMIC is not set
CONFIG_PINCTRL_SC7180=y
# CONFIG_PINCTRL_SDM660 is not set
CONFIG_PINCTRL_SDM845=y
CONFIG_PINCTRL_SM8150=y
# CONFIG_PINCTRL_SM8250 is not set

#
# Renesas pinctrl drivers
#
CONFIG_PINCTRL_RENESAS=y
CONFIG_PINCTRL_SH_PFC=y
CONFIG_PINCTRL_PFC_R8A77995=y
CONFIG_PINCTRL_PFC_R8A77990=y
CONFIG_PINCTRL_PFC_R8A77950=y
CONFIG_PINCTRL_PFC_R8A77951=y
CONFIG_PINCTRL_PFC_R8A77965=y
CONFIG_PINCTRL_PFC_R8A77960=y
CONFIG_PINCTRL_PFC_R8A77961=y
CONFIG_PINCTRL_PFC_R8A77980=y
CONFIG_PINCTRL_PFC_R8A77970=y
CONFIG_PINCTRL_PFC_R8A774C0=y
CONFIG_PINCTRL_PFC_R8A774A1=y
CONFIG_PINCTRL_PFC_R8A774B1=y

# end of Renesas pinctrl drivers

CONFIG_PINCTRL_SAMSUNG=y
CONFIG_PINCTRL_EXYNOS=y
CONFIG_PINCTRL_EXYNOS_ARM64=y
# CONFIG_PINCTRL_SPRD_SC9860 is not set
CONFIG_PINCTRL_SUNXI=y
# CONFIG_PINCTRL_SUN4I_A10 is not set
# CONFIG_PINCTRL_SUN5I is not set
# CONFIG_PINCTRL_SUN6I_A31 is not set
# CONFIG_PINCTRL_SUN6I_A31_R is not set
# CONFIG_PINCTRL_SUN8I_A23 is not set
# CONFIG_PINCTRL_SUN8I_A33 is not set
# CONFIG_PINCTRL_SUN8I_A83T is not set
# CONFIG_PINCTRL_SUN8I_A83T_R is not set
# CONFIG_PINCTRL_SUN8I_A23_R is not set
# CONFIG_PINCTRL_SUN8I_H3 is not set
CONFIG_PINCTRL_SUN8I_H3_R=y
# CONFIG_PINCTRL_SUN8I_V3S is not set
# CONFIG_PINCTRL_SUN9I_A80 is not set
# CONFIG_PINCTRL_SUN9I_A80_R is not set
CONFIG_PINCTRL_SUN50I_A64=y
CONFIG_PINCTRL_SUN50I_A64_R=y
CONFIG_PINCTRL_SUN50I_A100=y
CONFIG_PINCTRL_SUN50I_A100_R=y
CONFIG_PINCTRL_SUN50I_H5=y
CONFIG_PINCTRL_SUN50I_H6=y
CONFIG_PINCTRL_SUN50I_H6_R=y
CONFIG_PINCTRL_TEGRA=y
CONFIG_PINCTRL_TEGRA124=y
CONFIG_PINCTRL_TEGRA210=y
CONFIG_PINCTRL_TEGRA194=y
CONFIG_PINCTRL_TEGRA_XUSB=y
CONFIG_PINCTRL_UNIPHIER=y
# CONFIG_PINCTRL_UNIPHIER_LD4 is not set
# CONFIG_PINCTRL_UNIPHIER_PRO4 is not set
# CONFIG_PINCTRL_UNIPHIER_SLD8 is not set
# CONFIG_PINCTRL_UNIPHIER_PRO5 is not set
# CONFIG_PINCTRL_UNIPHIER_PXS2 is not set
# CONFIG_PINCTRL_UNIPHIER_LD6B is not set
CONFIG_PINCTRL_UNIPHIER_LD11=y
CONFIG_PINCTRL_UNIPHIER_LD20=y
CONFIG_PINCTRL_UNIPHIER_PXS3=y

#
# MediaTek pinctrl drivers
#
CONFIG_EINT_MTK=y
CONFIG_PINCTRL_MTK=y
CONFIG_PINCTRL_MTK_V2=y
CONFIG_PINCTRL_MTK_MOORE=y
CONFIG_PINCTRL_MTK_PARIS=y
CONFIG_PINCTRL_MT2712=y
CONFIG_PINCTRL_MT6765=y
CONFIG_PINCTRL_MT6779=y
CONFIG_PINCTRL_MT6797=y
CONFIG_PINCTRL_MT7622=y
CONFIG_PINCTRL_MT8167=y
CONFIG_PINCTRL_MT8173=y
CONFIG_PINCTRL_MT8183=y
CONFIG_PINCTRL_MT8192=y
CONFIG_PINCTRL_MT8516=y

# end of MediaTek pinctrl drivers

# CONFIG_PINCTRL_ZX296718 is not set
CONFIG_PINCTRL_MESON=y
CONFIG_PINCTRL_MESON_GXBB=y
CONFIG_PINCTRL_MESON_GXL=y
CONFIG_PINCTRL_MESON8_PMX=y
CONFIG_PINCTRL_MESON_AXG=y
CONFIG_PINCTRL_MESON_AXG_PMX=y
CONFIG_PINCTRL_MESON_G12A=y
CONFIG_PINCTRL_MESON_A1=y
CONFIG_GPIOLIB=y
CONFIG_GPIOLIB_FASTPATH_LIMIT=512
CONFIG_OF_GPIO=y
CONFIG_GPIO_ACPI=y
CONFIG_GPIOLIB_IRQCHIP=y
# CONFIG_DEBUG_GPIO is not set
# CONFIG_GPIO_SYSFS is not set
CONFIG_GPIO_CDEV=y
CONFIG_GPIO_CDEV_V1=y
CONFIG_GPIO_GENERIC=y

#
# Memory mapped GPIO drivers
#
# CONFIG_GPIO_74XX_MMIO is not set
CONFIG_GPIO_ALTERA=m
# CONFIG_GPIO_AMDPT is not set
CONFIG_GPIO_RASPBERRYPI_EXP=y
CONFIG_GPIO_BCM_XGS_IPROC=y
CONFIG_GPIO_BRCMSTB=y
# CONFIG_GPIO_CADENCE is not set
# CONFIG_GPIO_DAVINCI is not set
CONFIG_GPIO_DWAPB=y
# CONFIG_GPIO_EIC_SPRD is not set
# CONFIG_GPIO_EXAR is not set
# CONFIG_GPIO_FTGPIO010 is not set
CONFIG_GPIO_GENERIC_PLATFORM=y
# CONFIG_GPIO_GRGPIO is not set
# CONFIG_GPIO_HLWD is not set
# CONFIG_GPIO_LOGICVC is not set
CONFIG_GPIO_MB86S7X=y
CONFIG_GPIO_MPC8XXX=y
CONFIG_GPIO_MVEBU=y
CONFIG_GPIO_MXC=y
CONFIG_GPIO_PL061=y
CONFIG_GPIO_RCAR=y
# CONFIG_GPIO_SAMA5D2_PIOBU is not set
# CONFIG_GPIO_SIFIVE is not set
# CONFIG_GPIO_SPRD is not set
# CONFIG_GPIO_SYSCON is not set
CONFIG_GPIO_TEGRA=y
CONFIG_GPIO_TEGRA186=y
# CONFIG_GPIO_THUNDERX is not set
CONFIG_GPIO_UNIPHIER=y
CONFIG_GPIO_WCD934X=m
CONFIG_GPIO_XGENE=y
CONFIG_GPIO_XGENE_SB=y
# CONFIG_GPIO_XILINX is not set
# CONFIG_GPIO_XLP is not set
# CONFIG_GPIO_ZYNQ is not set
# CONFIG_GPIO_ZX is not set
# CONFIG_GPIO_AMD_FCH is not set

# end of Memory mapped GPIO drivers

#
# I2C GPIO expanders
#
# CONFIG_GPIO_ADP5588 is not set
# CONFIG_GPIO_ADNP is not set
# CONFIG_GPIO_GW_PLD is not set
# CONFIG_GPIO_MAX7300 is not set
CONFIG_GPIO_MAX732X=y
# CONFIG_GPIO_MAX732X_IRQ is not set
CONFIG_GPIO_PCA953X=y
CONFIG_GPIO_PCA953X_IRQ=y
# CONFIG_GPIO_PCA9570 is not set
# CONFIG_GPIO_PCF857X is not set
# CONFIG_GPIO_TPIC2810 is not set

# end of I2C GPIO expanders

#
# MFD GPIO expanders
#
CONFIG_GPIO_BD9571MWV=m
CONFIG_GPIO_MAX77620=y

# end of MFD GPIO expanders

#
# PCI GPIO expanders
#
# CONFIG_GPIO_BT8XX is not set
# CONFIG_GPIO_PCI_IDIO_16 is not set
# CONFIG_GPIO_PCIE_IDIO_24 is not set
# CONFIG_GPIO_RDC321X is not set

# end of PCI GPIO expanders

#
# SPI GPIO expanders
#
# CONFIG_GPIO_74X164 is not set
# CONFIG_GPIO_MAX3191X is not set
# CONFIG_GPIO_MAX7301 is not set
# CONFIG_GPIO_MC33880 is not set
# CONFIG_GPIO_PISOSR is not set
# CONFIG_GPIO_XRA1403 is not set

# end of SPI GPIO expanders

#
# USB GPIO expanders
#

# end of USB GPIO expanders

# CONFIG_GPIO_AGGREGATOR is not set
# CONFIG_GPIO_MOCKUP is not set
# CONFIG_W1 is not set CONFIG_POWER_RESET=y CONFIG_POWER_RESET_BRCMSTB=y
# CONFIG_POWER_RESET_GPIO is not set
# CONFIG_POWER_RESET_GPIO_RESTART is not set # CONFIG_POWER_RESET_HISI is not set
# CONFIG_POWER_RESET_LINKSTATION is not set CONFIG_POWER_RESET_MSM=y
# CONFIG_POWER_RESET_QCOM_PON is not set
# CONFIG_POWER_RESET_LTC2952 is not set
# CONFIG_POWER_RESET_RESTART is not set
# CONFIG_POWER_RESET_VEXPRESS is not set CONFIG_POWER_RESET_XGENE=y CONFIG_POWER_RESET_SYSCON=y
# CONFIG_POWER_RESET_SYSCON_POWEROFF is not set # CONFIG_POWER_RESET_ZX is not set CONFIG_REBOOT_MODE=y CONFIG_SYSCON_REBOOT_MODE=y
# CONFIG_NVMEM_REBOOT_MODE is not set CONFIG_POWER_SUPPLY=y
# CONFIG_POWER_SUPPLY_DEBUG is not set CONFIG_POWER_SUPPLY_HWMON=y
# CONFIG_PDA_POWER is not set
# CONFIG_GENERIC_ADC_BATTERY is not set CONFIG_TEST_POWER=m
# CONFIG_CHARGER_ADP5061 is not set
# CONFIG_BATTERY_CW2015 is not set
# CONFIG_BATTERY_DS2780 is not set
# CONFIG_BATTERY_DS2781 is not set
# CONFIG_BATTERY_DS2782 is not set CONFIG_BATTERY_SBS=m
# CONFIG_CHARGER_SBS is not set
# CONFIG_MANAGER_SBS is not set CONFIG_BATTERY_BQ27XXX=y CONFIG_BATTERY_BQ27XXX_I2C=y
# CONFIG_BATTERY_BQ27XXX_DT_UPDATES_NVM is not set # CONFIG_AXP20X_POWER is not set
# CONFIG_AXP288_FUEL_GAUGE is not set
# CONFIG_BATTERY_MAX17040 is not set
# CONFIG_BATTERY_MAX17042 is not set
# CONFIG_CHARGER_ISP1704 is not set
# CONFIG_CHARGER_MAX8903 is not set
# CONFIG_CHARGER_LP8727 is not set
# CONFIG_CHARGER_GPIO is not set
# CONFIG_CHARGER_MANAGER is not set
# CONFIG_CHARGER_LT3651 is not set
# CONFIG_CHARGER_DETECTOR_MAX14656 is not set # CONFIG_CHARGER_QCOM_SMBB is not set
# CONFIG_CHARGER_BQ2415X is not set
# CONFIG_CHARGER_BQ24190 is not set
# CONFIG_CHARGER_BQ24257 is not set
# CONFIG_CHARGER_BQ24735 is not set
# CONFIG_CHARGER_BQ2515X is not set
# CONFIG_CHARGER_BQ25890 is not set
# CONFIG_CHARGER_BQ25980 is not set
# CONFIG_CHARGER_SMB347 is not set
# CONFIG_BATTERY_GAUGE_LTC2941 is not set # CONFIG_CHARGER_RT9455 is not set
# CONFIG_CHARGER_CROS_USBPD is not set
# CONFIG_CHARGER_UCS1002 is not set
# CONFIG_CHARGER_BD99954 is not set CONFIG_HWMON=y
# CONFIG_HWMON_DEBUG_CHIP is not set

#
# Native drivers
#
# CONFIG_SENSORS_AD7314 is not set
# CONFIG_SENSORS_AD7414 is not set
# CONFIG_SENSORS_AD7418 is not set
# CONFIG_SENSORS_ADM1021 is not set
# CONFIG_SENSORS_ADM1025 is not set
# CONFIG_SENSORS_ADM1026 is not set
# CONFIG_SENSORS_ADM1029 is not set
# CONFIG_SENSORS_ADM1031 is not set
# CONFIG_SENSORS_ADM1177 is not set
# CONFIG_SENSORS_ADM9240 is not set
# CONFIG_SENSORS_ADT7310 is not set
# CONFIG_SENSORS_ADT7410 is not set
# CONFIG_SENSORS_ADT7411 is not set
# CONFIG_SENSORS_ADT7462 is not set
# CONFIG_SENSORS_ADT7470 is not set
# CONFIG_SENSORS_ADT7475 is not set
# CONFIG_SENSORS_AS370 is not set
# CONFIG_SENSORS_ASC7621 is not set
# CONFIG_SENSORS_AXI_FAN_CONTROL is not set
CONFIG_SENSORS_ARM_SCPI=y
# CONFIG_SENSORS_ASPEED is not set
# CONFIG_SENSORS_ATXP1 is not set
# CONFIG_SENSORS_CORSAIR_CPRO is not set
# CONFIG_SENSORS_CORSAIR_PSU is not set
# CONFIG_SENSORS_DRIVETEMP is not set
# CONFIG_SENSORS_DS620 is not set
# CONFIG_SENSORS_DS1621 is not set
# CONFIG_SENSORS_I5K_AMB is not set
# CONFIG_SENSORS_F71805F is not set
# CONFIG_SENSORS_F71882FG is not set
# CONFIG_SENSORS_F75375S is not set
# CONFIG_SENSORS_FTSTEUTATES is not set
# CONFIG_SENSORS_GL518SM is not set
# CONFIG_SENSORS_GL520SM is not set
# CONFIG_SENSORS_G760A is not set
# CONFIG_SENSORS_G762 is not set
# CONFIG_SENSORS_GPIO_FAN is not set
# CONFIG_SENSORS_HIH6130 is not set
# CONFIG_SENSORS_IBMAEM is not set
# CONFIG_SENSORS_IBMPEX is not set
# CONFIG_SENSORS_IIO_HWMON is not set
# CONFIG_SENSORS_IT87 is not set
# CONFIG_SENSORS_JC42 is not set
# CONFIG_SENSORS_POWR1220 is not set
# CONFIG_SENSORS_LINEAGE is not set
# CONFIG_SENSORS_LTC2945 is not set
# CONFIG_SENSORS_LTC2947_I2C is not set
# CONFIG_SENSORS_LTC2947_SPI is not set
# CONFIG_SENSORS_LTC2990 is not set
# CONFIG_SENSORS_LTC4151 is not set
# CONFIG_SENSORS_LTC4215 is not set
# CONFIG_SENSORS_LTC4222 is not set
# CONFIG_SENSORS_LTC4245 is not set
# CONFIG_SENSORS_LTC4260 is not set
# CONFIG_SENSORS_LTC4261 is not set
# CONFIG_SENSORS_MAX1111 is not set
# CONFIG_SENSORS_MAX16065 is not set
# CONFIG_SENSORS_MAX1619 is not set
# CONFIG_SENSORS_MAX1668 is not set
# CONFIG_SENSORS_MAX197 is not set
# CONFIG_SENSORS_MAX31722 is not set
# CONFIG_SENSORS_MAX31730 is not set
# CONFIG_SENSORS_MAX6621 is not set
# CONFIG_SENSORS_MAX6639 is not set
# CONFIG_SENSORS_MAX6642 is not set
# CONFIG_SENSORS_MAX6650 is not set
# CONFIG_SENSORS_MAX6697 is not set
# CONFIG_SENSORS_MAX31790 is not set
# CONFIG_SENSORS_MCP3021 is not set
# CONFIG_SENSORS_TC654 is not set
# CONFIG_SENSORS_MR75203 is not set
# CONFIG_SENSORS_ADCXX is not set
# CONFIG_SENSORS_LM63 is not set
# CONFIG_SENSORS_LM70 is not set
# CONFIG_SENSORS_LM73 is not set
# CONFIG_SENSORS_LM75 is not set
# CONFIG_SENSORS_LM77 is not set
# CONFIG_SENSORS_LM78 is not set
# CONFIG_SENSORS_LM80 is not set
# CONFIG_SENSORS_LM83 is not set
# CONFIG_SENSORS_LM85 is not set
# CONFIG_SENSORS_LM87 is not set
CONFIG_SENSORS_LM90=m
# CONFIG_SENSORS_LM92 is not set
# CONFIG_SENSORS_LM93 is not set
# CONFIG_SENSORS_LM95234 is not set
# CONFIG_SENSORS_LM95241 is not set
# CONFIG_SENSORS_LM95245 is not set
# CONFIG_SENSORS_PC87360 is not set
# CONFIG_SENSORS_PC87427 is not set
# CONFIG_SENSORS_NTC_THERMISTOR is not set
# CONFIG_SENSORS_NCT6683 is not set
# CONFIG_SENSORS_NCT6775 is not set
# CONFIG_SENSORS_NCT7802 is not set
# CONFIG_SENSORS_NCT7904 is not set
# CONFIG_SENSORS_NPCM7XX is not set
# CONFIG_SENSORS_OCC_P8_I2C is not set
# CONFIG_SENSORS_PCF8591 is not set
# CONFIG_PMBUS is not set
CONFIG_SENSORS_PWM_FAN=m
CONFIG_SENSORS_RASPBERRYPI_HWMON=m
# CONFIG_SENSORS_SHT15 is not set
# CONFIG_SENSORS_SHT21 is not set
# CONFIG_SENSORS_SHT3x is not set
# CONFIG_SENSORS_SHTC1 is not set
# CONFIG_SENSORS_SIS5595 is not set
# CONFIG_SENSORS_DME1737 is not set
# CONFIG_SENSORS_EMC1403 is not set
# CONFIG_SENSORS_EMC2103 is not set
# CONFIG_SENSORS_EMC6W201 is not set
# CONFIG_SENSORS_SMSC47M1 is not set
# CONFIG_SENSORS_SMSC47M192 is not set
# CONFIG_SENSORS_SMSC47B397 is not set
# CONFIG_SENSORS_SCH5627 is not set
# CONFIG_SENSORS_SCH5636 is not set
# CONFIG_SENSORS_STTS751 is not set
# CONFIG_SENSORS_SMM665 is not set
# CONFIG_SENSORS_ADC128D818 is not set
# CONFIG_SENSORS_ADS7828 is not set
# CONFIG_SENSORS_ADS7871 is not set
# CONFIG_SENSORS_AMC6821 is not set
# CONFIG_SENSORS_INA209 is not set
CONFIG_SENSORS_INA2XX=m
CONFIG_SENSORS_INA3221=m
# CONFIG_SENSORS_TC74 is not set
# CONFIG_SENSORS_THMC50 is not set
# CONFIG_SENSORS_TMP102 is not set
# CONFIG_SENSORS_TMP103 is not set
# CONFIG_SENSORS_TMP108 is not set
# CONFIG_SENSORS_TMP401 is not set
# CONFIG_SENSORS_TMP421 is not set
# CONFIG_SENSORS_TMP513 is not set
# CONFIG_SENSORS_VEXPRESS is not set
# CONFIG_SENSORS_VIA686A is not set
# CONFIG_SENSORS_VT1211 is not set
# CONFIG_SENSORS_VT8231 is not set
# CONFIG_SENSORS_W83773G is not set
# CONFIG_SENSORS_W83781D is not set
# CONFIG_SENSORS_W83791D is not set
# CONFIG_SENSORS_W83792D is not set
# CONFIG_SENSORS_W83793 is not set
# CONFIG_SENSORS_W83795 is not set
# CONFIG_SENSORS_W83L785TS is not set
# CONFIG_SENSORS_W83L786NG is not set
# CONFIG_SENSORS_W83627HF is not set
# CONFIG_SENSORS_W83627EHF is not set
# CONFIG_SENSORS_XGENE is not set

#
# ACPI drivers
#
# CONFIG_SENSORS_ACPI_POWER is not set CONFIG_THERMAL=y
# CONFIG_THERMAL_NETLINK is not set
# CONFIG_THERMAL_STATISTICS is not set CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS=0 CONFIG_THERMAL_HWMON=y
CONFIG_THERMAL_OF=y
# CONFIG_THERMAL_WRITABLE_TRIPS is not set CONFIG_THERMAL_DEFAULT_GOV_STEP_WISE=y
# CONFIG_THERMAL_DEFAULT_GOV_FAIR_SHARE is not set # CONFIG_THERMAL_DEFAULT_GOV_USER_SPACE is not set # CONFIG_THERMAL_DEFAULT_GOV_POWER_ALLOCATOR is not set # CONFIG_THERMAL_GOV_FAIR_SHARE is not set CONFIG_THERMAL_GOV_STEP_WISE=y
# CONFIG_THERMAL_GOV_BANG_BANG is not set
# CONFIG_THERMAL_GOV_USER_SPACE is not set CONFIG_THERMAL_GOV_POWER_ALLOCATOR=y CONFIG_CPU_THERMAL=y
CONFIG_CPU_FREQ_THERMAL=y
# CONFIG_DEVFREQ_THERMAL is not set CONFIG_THERMAL_EMULATION=y
# CONFIG_THERMAL_MMIO is not set CONFIG_HISI_THERMAL=y
# CONFIG_IMX_THERMAL is not set CONFIG_IMX_SC_THERMAL=m CONFIG_IMX8MM_THERMAL=m
# CONFIG_K3_THERMAL is not set
# CONFIG_MAX77620_THERMAL is not set CONFIG_QORIQ_THERMAL=m
CONFIG_SUN8I_THERMAL=y CONFIG_ROCKCHIP_THERMAL=m CONFIG_RCAR_THERMAL=y CONFIG_RCAR_GEN3_THERMAL=y CONFIG_ARMADA_THERMAL=y
CONFIG_MTK_THERMAL=y
CONFIG_AMLOGIC_THERMAL=y

#
# Broadcom thermal drivers
#
CONFIG_BCM2711_THERMAL=m
CONFIG_BCM2835_THERMAL=m
CONFIG_BRCMSTB_THERMAL=m
CONFIG_BCM_NS_THERMAL=y
CONFIG_BCM_SR_THERMAL=y

# end of Broadcom thermal drivers

#
# Samsung thermal drivers
#
CONFIG_EXYNOS_THERMAL=y

# end of Samsung thermal drivers

#
# NVIDIA Tegra thermal drivers
#
# CONFIG_TEGRA_SOCTHERM is not set
CONFIG_TEGRA_BPMP_THERMAL=m

# end of NVIDIA Tegra thermal drivers

# CONFIG_GENERIC_ADC_THERMAL is not set

#
# Qualcomm thermal drivers
#
CONFIG_QCOM_TSENS=y
CONFIG_QCOM_SPMI_TEMP_ALARM=m

# end of Qualcomm thermal drivers

# CONFIG_ZX2967_THERMAL is not set
CONFIG_UNIPHIER_THERMAL=y
# CONFIG_SPRD_THERMAL is not set
CONFIG_WATCHDOG=y
CONFIG_WATCHDOG_CORE=y
CONFIG_WATCHDOG_NOWAYOUT=y
CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED=y
CONFIG_WATCHDOG_OPEN_TIMEOUT=0
CONFIG_WATCHDOG_SYSFS=y

#
# Watchdog Pretimeout Governors
#
CONFIG_WATCHDOG_PRETIMEOUT_GOV=y CONFIG_WATCHDOG_PRETIMEOUT_GOV_SEL=m CONFIG_WATCHDOG_PRETIMEOUT_GOV_NOOP=m CONFIG_WATCHDOG_PRETIMEOUT_GOV_PANIC=m
# CONFIG_WATCHDOG_PRETIMEOUT_DEFAULT_GOV_NOOP is not set CONFIG_WATCHDOG_PRETIMEOUT_DEFAULT_GOV_PANIC=y

#
# Watchdog Device Drivers
#
CONFIG_SOFT_WATCHDOG=m
CONFIG_SOFT_WATCHDOG_PRETIMEOUT=y
CONFIG_GPIO_WATCHDOG=m
# CONFIG_WDAT_WDT is not set
CONFIG_XILINX_WATCHDOG=m
CONFIG_ZIIRAVE_WATCHDOG=m
CONFIG_ARM_SP805_WATCHDOG=y
CONFIG_ARM_SBSA_WATCHDOG=y
CONFIG_ARMADA_37XX_WATCHDOG=m
CONFIG_CADENCE_WATCHDOG=m
CONFIG_S3C2410_WATCHDOG=y
CONFIG_DW_WATCHDOG=y
CONFIG_K3_RTI_WATCHDOG=m
CONFIG_SUNXI_WATCHDOG=m
CONFIG_MAX63XX_WATCHDOG=m
CONFIG_MAX77620_WATCHDOG=m
CONFIG_IMX2_WDT=y
CONFIG_IMX_SC_WDT=m
# CONFIG_IMX7ULP_WDT is not set
CONFIG_TEGRA_WATCHDOG=m
CONFIG_QCOM_WDT=m
CONFIG_MESON_GXBB_WATCHDOG=m
CONFIG_MESON_WATCHDOG=m
CONFIG_MEDIATEK_WATCHDOG=m
CONFIG_ARM_SMC_WATCHDOG=y
CONFIG_RENESAS_WDT=y
# CONFIG_RENESAS_RZAWDT is not set
CONFIG_ZX2967_WATCHDOG=m
CONFIG_UNIPHIER_WATCHDOG=y
CONFIG_SPRD_WATCHDOG=m
CONFIG_PM8916_WATCHDOG=m
# CONFIG_ALIM7101_WDT is not set
# CONFIG_I6300ESB_WDT is not set
CONFIG_BCM2835_WDT=y
# CONFIG_BCM7038_WDT is not set
# CONFIG_MEN_A21_WDT is not set
# CONFIG_XEN_WDT is not set

#
# PCI-based Watchdog Cards
#
CONFIG_PCIPCWATCHDOG=m
# CONFIG_WDTPCI is not set

#
# USB-based Watchdog Cards
#
CONFIG_USBPCWATCHDOG=m
CONFIG_SSB_POSSIBLE=y
# CONFIG_SSB is not set
CONFIG_BCMA_POSSIBLE=y
# CONFIG_BCMA is not set

#
# Multifunction device drivers
#
CONFIG_MFD_CORE=y
CONFIG_MFD_ALTERA_SYSMGR=y
# CONFIG_MFD_ACT8945A is not set
# CONFIG_MFD_SUN4I_GPADC is not set
# CONFIG_MFD_AS3711 is not set
# CONFIG_MFD_AS3722 is not set
# CONFIG_PMIC_ADP5520 is not set
# CONFIG_MFD_AAT2870_CORE is not set
# CONFIG_MFD_ATMEL_FLEXCOM is not set
# CONFIG_MFD_ATMEL_HLCDC is not set
# CONFIG_MFD_BCM590XX is not set
CONFIG_MFD_BD9571MWV=y
# CONFIG_MFD_AC100 is not set
CONFIG_MFD_AXP20X=y
CONFIG_MFD_AXP20X_I2C=y
CONFIG_MFD_AXP20X_RSB=y
CONFIG_MFD_CROS_EC_DEV=y
# CONFIG_MFD_MADERA is not set
# CONFIG_PMIC_DA903X is not set
# CONFIG_MFD_DA9052_SPI is not set
# CONFIG_MFD_DA9052_I2C is not set
# CONFIG_MFD_DA9055 is not set
# CONFIG_MFD_DA9062 is not set
# CONFIG_MFD_DA9063 is not set
# CONFIG_MFD_DA9150 is not set
# CONFIG_MFD_DLN2 is not set
CONFIG_MFD_EXYNOS_LPASS=m
# CONFIG_MFD_GATEWORKS_GSC is not set
# CONFIG_MFD_MC13XXX_SPI is not set
# CONFIG_MFD_MC13XXX_I2C is not set
# CONFIG_MFD_MP2629 is not set
CONFIG_MFD_HI6421_PMIC=y
CONFIG_MFD_HI655X_PMIC=y
# CONFIG_HTC_PASIC3 is not set
# CONFIG_HTC_I2CPLD is not set
# CONFIG_LPC_ICH is not set
# CONFIG_LPC_SCH is not set
# CONFIG_MFD_INTEL_PMT is not set
# CONFIG_MFD_IQS62X is not set
# CONFIG_MFD_JANZ_CMODIO is not set
# CONFIG_MFD_KEMPLD is not set
# CONFIG_MFD_88PM800 is not set
# CONFIG_MFD_88PM805 is not set
# CONFIG_MFD_88PM860X is not set
# CONFIG_MFD_MAX14577 is not set
CONFIG_MFD_MAX77620=y
# CONFIG_MFD_MAX77650 is not set
# CONFIG_MFD_MAX77686 is not set
# CONFIG_MFD_MAX77693 is not set
# CONFIG_MFD_MAX77843 is not set
# CONFIG_MFD_MAX8907 is not set
# CONFIG_MFD_MAX8925 is not set
# CONFIG_MFD_MAX8997 is not set
# CONFIG_MFD_MAX8998 is not set
# CONFIG_MFD_MT6360 is not set
# CONFIG_MFD_MT6397 is not set
# CONFIG_MFD_MENF21BMC is not set
# CONFIG_EZX_PCAP is not set
# CONFIG_MFD_CPCAP is not set
# CONFIG_MFD_VIPERBOARD is not set
# CONFIG_MFD_RETU is not set
# CONFIG_MFD_PCF50633 is not set
# CONFIG_MFD_QCOM_RPM is not set
CONFIG_MFD_SPMI_PMIC=y
# CONFIG_MFD_RDC321X is not set
# CONFIG_MFD_RT5033 is not set
# CONFIG_MFD_RC5T583 is not set
CONFIG_MFD_RK808=y
# CONFIG_MFD_RN5T618 is not set
CONFIG_MFD_SEC_CORE=y
# CONFIG_MFD_SI476X_CORE is not set
# CONFIG_MFD_SL28CPLD is not set
# CONFIG_MFD_SM501 is not set
# CONFIG_MFD_SKY81452 is not set
# CONFIG_MFD_SC27XX_PMIC is not set
# CONFIG_ABX500_CORE is not set
# CONFIG_MFD_STMPE is not set
CONFIG_MFD_SUN6I_PRCM=y
CONFIG_MFD_SYSCON=y
# CONFIG_MFD_TI_AM335X_TSCADC is not set
# CONFIG_MFD_LP3943 is not set
# CONFIG_MFD_LP8788 is not set
# CONFIG_MFD_TI_LMU is not set
# CONFIG_MFD_PALMAS is not set
# CONFIG_TPS6105X is not set
# CONFIG_TPS65010 is not set
# CONFIG_TPS6507X is not set
# CONFIG_MFD_TPS65086 is not set
# CONFIG_MFD_TPS65090 is not set
# CONFIG_MFD_TPS65217 is not set
# CONFIG_MFD_TPS68470 is not set
# CONFIG_MFD_TI_LP873X is not set
# CONFIG_MFD_TI_LP87565 is not set
# CONFIG_MFD_TPS65218 is not set
# CONFIG_MFD_TPS6586X is not set
# CONFIG_MFD_TPS65910 is not set
# CONFIG_MFD_TPS65912_I2C is not set
# CONFIG_MFD_TPS65912_SPI is not set
# CONFIG_MFD_TPS80031 is not set
# CONFIG_TWL4030_CORE is not set
# CONFIG_TWL6040_CORE is not set
# CONFIG_MFD_WL1273_CORE is not set
# CONFIG_MFD_LM3533 is not set
# CONFIG_MFD_TC3589X is not set
# CONFIG_MFD_TQMX86 is not set
# CONFIG_MFD_VX855 is not set
# CONFIG_MFD_LOCHNAGAR is not set
# CONFIG_MFD_ARIZONA_I2C is not set
# CONFIG_MFD_ARIZONA_SPI is not set
# CONFIG_MFD_WM8400 is not set
# CONFIG_MFD_WM831X_I2C is not set
# CONFIG_MFD_WM831X_SPI is not set
# CONFIG_MFD_WM8350_I2C is not set
# CONFIG_MFD_WM8994 is not set
CONFIG_MFD_ROHM_BD718XX=y
# CONFIG_MFD_ROHM_BD70528 is not set
# CONFIG_MFD_ROHM_BD71828 is not set
# CONFIG_MFD_STPMIC1 is not set
# CONFIG_MFD_STMFX is not set
CONFIG_MFD_WCD934X=m
# CONFIG_MFD_KHADAS_MCU is not set
CONFIG_MFD_VEXPRESS_SYSREG=y
# CONFIG_RAVE_SP_CORE is not set
# CONFIG_MFD_INTEL_M10_BMC is not set

# end of Multifunction device drivers

CONFIG_REGULATOR=y
# CONFIG_REGULATOR_DEBUG is not set CONFIG_REGULATOR_FIXED_VOLTAGE=y
# CONFIG_REGULATOR_VIRTUAL_CONSUMER is not set
# CONFIG_REGULATOR_USERSPACE_CONSUMER is not set
# CONFIG_REGULATOR_88PG86X is not set
# CONFIG_REGULATOR_ACT8865 is not set
# CONFIG_REGULATOR_AD5398 is not set
# CONFIG_REGULATOR_ANATOP is not set CONFIG_REGULATOR_AXP20X=y CONFIG_REGULATOR_BD718XX=y CONFIG_REGULATOR_BD9571MWV=y
# CONFIG_REGULATOR_CROS_EC is not set
# CONFIG_REGULATOR_DA9121 is not set
# CONFIG_REGULATOR_DA9210 is not set
# CONFIG_REGULATOR_DA9211 is not set CONFIG_REGULATOR_FAN53555=y
# CONFIG_REGULATOR_FAN53880 is not set CONFIG_REGULATOR_GPIO=y
# CONFIG_REGULATOR_HI6421 is not set CONFIG_REGULATOR_HI6421V530=y CONFIG_REGULATOR_HI655X=y
# CONFIG_REGULATOR_ISL9305 is not set
# CONFIG_REGULATOR_ISL6271A is not set
# CONFIG_REGULATOR_LP3971 is not set
# CONFIG_REGULATOR_LP3972 is not set
# CONFIG_REGULATOR_LP872X is not set
# CONFIG_REGULATOR_LP8755 is not set
# CONFIG_REGULATOR_LTC3589 is not set
# CONFIG_REGULATOR_LTC3676 is not set
# CONFIG_REGULATOR_MAX1586 is not set CONFIG_REGULATOR_MAX77620=y
# CONFIG_REGULATOR_MAX8649 is not set
# CONFIG_REGULATOR_MAX8660 is not set
# CONFIG_REGULATOR_MAX8952 is not set CONFIG_REGULATOR_MAX8973=y
# CONFIG_REGULATOR_MAX77826 is not set
# CONFIG_REGULATOR_MCP16502 is not set
# CONFIG_REGULATOR_MP5416 is not set
# CONFIG_REGULATOR_MP8859 is not set
# CONFIG_REGULATOR_MP886X is not set
# CONFIG_REGULATOR_MPQ7920 is not set
# CONFIG_REGULATOR_MT6311 is not set
# CONFIG_REGULATOR_PCA9450 is not set CONFIG_REGULATOR_PFUZE100=y
# CONFIG_REGULATOR_PV88060 is not set
# CONFIG_REGULATOR_PV88080 is not set
# CONFIG_REGULATOR_PV88090 is not set CONFIG_REGULATOR_PWM=y CONFIG_REGULATOR_QCOM_RPMH=y CONFIG_REGULATOR_QCOM_SMD_RPM=y CONFIG_REGULATOR_QCOM_SPMI=y
# CONFIG_REGULATOR_QCOM_USB_VBUS is not set
# CONFIG_REGULATOR_RASPBERRYPI_TOUCHSCREEN_ATTINY is not set CONFIG_REGULATOR_RK808=y
CONFIG_REGULATOR_ROHM=y
# CONFIG_REGULATOR_RT4801 is not set
# CONFIG_REGULATOR_RTMV20 is not set
# CONFIG_REGULATOR_S2MPA01 is not set CONFIG_REGULATOR_S2MPS11=y
# CONFIG_REGULATOR_S5M8767 is not set
# CONFIG_REGULATOR_SLG51000 is not set
# CONFIG_REGULATOR_SY8106A is not set
# CONFIG_REGULATOR_SY8824X is not set
# CONFIG_REGULATOR_SY8827N is not set
# CONFIG_REGULATOR_TPS51632 is not set
# CONFIG_REGULATOR_TPS62360 is not set
# CONFIG_REGULATOR_TPS65023 is not set
# CONFIG_REGULATOR_TPS6507X is not set
# CONFIG_REGULATOR_TPS65132 is not set
# CONFIG_REGULATOR_TPS6524X is not set CONFIG_REGULATOR_UNIPHIER=y CONFIG_REGULATOR_VCTRL=m
# CONFIG_REGULATOR_VEXPRESS is not set
# CONFIG_REGULATOR_VQMMC_IPQ4019 is not set
# CONFIG_REGULATOR_QCOM_LABIBB is not set CONFIG_RC_CORE=m
CONFIG_RC_MAP=m
# CONFIG_LIRC is not set
CONFIG_RC_DECODERS=y
# CONFIG_IR_NEC_DECODER is not set
# CONFIG_IR_RC5_DECODER is not set
# CONFIG_IR_RC6_DECODER is not set
# CONFIG_IR_JVC_DECODER is not set
# CONFIG_IR_SONY_DECODER is not set
# CONFIG_IR_SANYO_DECODER is not set
# CONFIG_IR_SHARP_DECODER is not set
# CONFIG_IR_MCE_KBD_DECODER is not set
# CONFIG_IR_XMP_DECODER is not set
# CONFIG_IR_IMON_DECODER is not set
# CONFIG_IR_RCMM_DECODER is not set CONFIG_RC_DEVICES=y
# CONFIG_RC_ATI_REMOTE is not set
# CONFIG_IR_ENE is not set
# CONFIG_IR_HIX5HD2 is not set
# CONFIG_IR_IMON is not set
# CONFIG_IR_IMON_RAW is not set
# CONFIG_IR_MCEUSB is not set
# CONFIG_IR_ITE_CIR is not set
# CONFIG_IR_FINTEK is not set
CONFIG_IR_MESON=m
# CONFIG_IR_MTK is not set
# CONFIG_IR_NUVOTON is not set
# CONFIG_IR_REDRAT3 is not set
# CONFIG_IR_STREAMZAP is not set
# CONFIG_IR_IGORPLUGUSB is not set
# CONFIG_IR_IGUANA is not set
# CONFIG_IR_TTUSBIR is not set
# CONFIG_RC_LOOPBACK is not set
# CONFIG_IR_GPIO_CIR is not set
CONFIG_IR_SUNXI=m
# CONFIG_IR_SERIAL is not set
# CONFIG_IR_SIR is not set
# CONFIG_RC_XBOX_DVD is not set
# CONFIG_IR_ZX is not set
# CONFIG_IR_TOY is not set
CONFIG_CEC_CORE=m
CONFIG_CEC_NOTIFIER=y
# CONFIG_MEDIA_CEC_RC is not set
# CONFIG_MEDIA_CEC_SUPPORT is not set CONFIG_MEDIA_SUPPORT=m CONFIG_MEDIA_SUPPORT_FILTER=y CONFIG_MEDIA_SUBDRV_AUTOSELECT=y

#
# Media device types
#
CONFIG_MEDIA_CAMERA_SUPPORT=y
CONFIG_MEDIA_ANALOG_TV_SUPPORT=y
CONFIG_MEDIA_DIGITAL_TV_SUPPORT=y
# CONFIG_MEDIA_RADIO_SUPPORT is not set
CONFIG_MEDIA_SDR_SUPPORT=y
CONFIG_MEDIA_PLATFORM_SUPPORT=y
# CONFIG_MEDIA_TEST_SUPPORT is not set

# end of Media device types

CONFIG_VIDEO_DEV=m
CONFIG_MEDIA_CONTROLLER=y
CONFIG_DVB_CORE=m

#
# Video4Linux options
#
CONFIG_VIDEO_V4L2=m
CONFIG_VIDEO_V4L2_I2C=y
CONFIG_VIDEO_V4L2_SUBDEV_API=y
# CONFIG_VIDEO_ADV_DEBUG is not set
# CONFIG_VIDEO_FIXED_MINOR_RANGES is not set
CONFIG_V4L2_MEM2MEM_DEV=m
CONFIG_V4L2_FWNODE=m

# end of Video4Linux options

#
# Media controller options
#
# CONFIG_MEDIA_CONTROLLER_DVB is not set

# end of Media controller options

#
# Digital TV options
#
# CONFIG_DVB_MMAP is not set
# CONFIG_DVB_NET is not set
CONFIG_DVB_MAX_ADAPTERS=16
CONFIG_DVB_DYNAMIC_MINORS=y
# CONFIG_DVB_DEMUX_SECTION_LOSS_LOG is not set
# CONFIG_DVB_ULE_DEBUG is not set

# end of Digital TV options

#
# Media drivers
#

#
# Drivers filtered as selected at 'Filter media drivers' #
CONFIG_MEDIA_USB_SUPPORT=y

#
# Webcam devices
#
CONFIG_USB_VIDEO_CLASS=m
CONFIG_USB_VIDEO_CLASS_INPUT_EVDEV=y
CONFIG_USB_GSPCA=m
# CONFIG_USB_M5602 is not set
# CONFIG_USB_STV06XX is not set
# CONFIG_USB_GL860 is not set
# CONFIG_USB_GSPCA_BENQ is not set
# CONFIG_USB_GSPCA_CONEX is not set
# CONFIG_USB_GSPCA_CPIA1 is not set
# CONFIG_USB_GSPCA_DTCS033 is not set
# CONFIG_USB_GSPCA_ETOMS is not set
# CONFIG_USB_GSPCA_FINEPIX is not set
# CONFIG_USB_GSPCA_JEILINJ is not set
# CONFIG_USB_GSPCA_JL2005BCD is not set
# CONFIG_USB_GSPCA_KINECT is not set
# CONFIG_USB_GSPCA_KONICA is not set
# CONFIG_USB_GSPCA_MARS is not set
# CONFIG_USB_GSPCA_MR97310A is not set
# CONFIG_USB_GSPCA_NW80X is not set
# CONFIG_USB_GSPCA_OV519 is not set
# CONFIG_USB_GSPCA_OV534 is not set
# CONFIG_USB_GSPCA_OV534_9 is not set
# CONFIG_USB_GSPCA_PAC207 is not set
# CONFIG_USB_GSPCA_PAC7302 is not set
# CONFIG_USB_GSPCA_PAC7311 is not set
# CONFIG_USB_GSPCA_SE401 is not set
# CONFIG_USB_GSPCA_SN9C2028 is not set
# CONFIG_USB_GSPCA_SN9C20X is not set
# CONFIG_USB_GSPCA_SONIXB is not set
# CONFIG_USB_GSPCA_SONIXJ is not set
# CONFIG_USB_GSPCA_SPCA500 is not set
# CONFIG_USB_GSPCA_SPCA501 is not set
# CONFIG_USB_GSPCA_SPCA505 is not set
# CONFIG_USB_GSPCA_SPCA506 is not set
# CONFIG_USB_GSPCA_SPCA508 is not set
# CONFIG_USB_GSPCA_SPCA561 is not set
# CONFIG_USB_GSPCA_SPCA1528 is not set
# CONFIG_USB_GSPCA_SQ905 is not set
# CONFIG_USB_GSPCA_SQ905C is not set
# CONFIG_USB_GSPCA_SQ930X is not set
# CONFIG_USB_GSPCA_STK014 is not set
# CONFIG_USB_GSPCA_STK1135 is not set
# CONFIG_USB_GSPCA_STV0680 is not set
# CONFIG_USB_GSPCA_SUNPLUS is not set
# CONFIG_USB_GSPCA_T613 is not set
# CONFIG_USB_GSPCA_TOPRO is not set
# CONFIG_USB_GSPCA_TOUPTEK is not set
# CONFIG_USB_GSPCA_TV8532 is not set
# CONFIG_USB_GSPCA_VC032X is not set
# CONFIG_USB_GSPCA_VICAM is not set
# CONFIG_USB_GSPCA_XIRLINK_CIT is not set
# CONFIG_USB_GSPCA_ZC3XX is not set
# CONFIG_USB_PWC is not set
# CONFIG_VIDEO_CPIA2 is not set
# CONFIG_USB_ZR364XX is not set
# CONFIG_USB_STKWEBCAM is not set
# CONFIG_USB_S2255 is not set
# CONFIG_VIDEO_USBTV is not set

#
# Analog TV USB devices
#
# CONFIG_VIDEO_PVRUSB2 is not set
# CONFIG_VIDEO_HDPVR is not set
# CONFIG_VIDEO_STK1160_COMMON is not set
# CONFIG_VIDEO_GO7007 is not set

#
# Analog/digital TV USB devices
#
# CONFIG_VIDEO_AU0828 is not set
# CONFIG_VIDEO_CX231XX is not set
# CONFIG_VIDEO_TM6000 is not set

#
# Digital TV USB devices
#
# CONFIG_DVB_USB is not set
# CONFIG_DVB_USB_V2 is not set
# CONFIG_DVB_TTUSB_BUDGET is not set
# CONFIG_DVB_TTUSB_DEC is not set
# CONFIG_SMS_USB_DRV is not set
# CONFIG_DVB_B2C2_FLEXCOP_USB is not set
# CONFIG_DVB_AS102 is not set

#
# Webcam, TV (analog/digital) USB devices
#
# CONFIG_VIDEO_EM28XX is not set

#
# Software defined radio USB devices
#
# CONFIG_USB_AIRSPY is not set
# CONFIG_USB_HACKRF is not set
# CONFIG_USB_MSI2500 is not set
# CONFIG_MEDIA_PCI_SUPPORT is not set
CONFIG_VIDEOBUF2_CORE=m
CONFIG_VIDEOBUF2_V4L2=m
CONFIG_VIDEOBUF2_MEMOPS=m
CONFIG_VIDEOBUF2_DMA_CONTIG=m
CONFIG_VIDEOBUF2_VMALLOC=m
CONFIG_VIDEOBUF2_DMA_SG=m
CONFIG_V4L_PLATFORM_DRIVERS=y
# CONFIG_VIDEO_CAFE_CCIC is not set
# CONFIG_VIDEO_CADENCE is not set
# CONFIG_VIDEO_ASPEED is not set
# CONFIG_VIDEO_MUX is not set
CONFIG_VIDEO_QCOM_CAMSS=m
# CONFIG_VIDEO_SAMSUNG_EXYNOS4_IS is not set
# CONFIG_VIDEO_XILINX is not set
CONFIG_VIDEO_RCAR_CSI2=m
CONFIG_VIDEO_RCAR_VIN=m
# CONFIG_VIDEO_SUN4I_CSI is not set
CONFIG_VIDEO_SUN6I_CSI=m
# CONFIG_VIDEO_TI_CAL is not set
CONFIG_V4L_MEM2MEM_DRIVERS=y
# CONFIG_VIDEO_CODA is not set
# CONFIG_VIDEO_IMX_PXP is not set
# CONFIG_VIDEO_MEDIATEK_VPU is not set
# CONFIG_VIDEO_MEM2MEM_DEINTERLACE is not set
# CONFIG_VIDEO_SAMSUNG_S5P_G2D is not set
CONFIG_VIDEO_SAMSUNG_S5P_JPEG=m
CONFIG_VIDEO_SAMSUNG_S5P_MFC=m
CONFIG_VIDEO_SAMSUNG_EXYNOS_GSC=m
CONFIG_VIDEO_RENESAS_FDP1=m
# CONFIG_VIDEO_RENESAS_JPU is not set
CONFIG_VIDEO_RENESAS_FCP=m
CONFIG_VIDEO_RENESAS_VSP1=m
# CONFIG_VIDEO_ROCKCHIP_RGA is not set
# CONFIG_VIDEO_QCOM_VENUS is not set
# CONFIG_VIDEO_SUN8I_DEINTERLACE is not set
# CONFIG_VIDEO_SUN8I_ROTATE is not set
# CONFIG_DVB_PLATFORM_DRIVERS is not set
CONFIG_SDR_PLATFORM_DRIVERS=y
CONFIG_VIDEO_RCAR_DRIF=m

#
# MMC/SDIO DVB adapters
#
# CONFIG_SMS_SDIO_DRV is not set

# end of Media drivers

CONFIG_MEDIA_HIDE_ANCILLARY_SUBDRV=y

#
# Media ancillary drivers
#
CONFIG_MEDIA_ATTACH=y

#
# IR I2C driver auto-selected by 'Autoselect ancillary drivers' #
CONFIG_VIDEO_IR_I2C=m

#
# audio, video and radio I2C drivers auto-selected by 'Autoselect ancillary drivers' #

#
# Video and audio decoders
#

#
# Camera sensor devices
#
# CONFIG_VIDEO_HI556 is not set
# CONFIG_VIDEO_IMX214 is not set
# CONFIG_VIDEO_IMX219 is not set
# CONFIG_VIDEO_IMX258 is not set
# CONFIG_VIDEO_IMX274 is not set
# CONFIG_VIDEO_IMX290 is not set
# CONFIG_VIDEO_IMX319 is not set
# CONFIG_VIDEO_IMX355 is not set
# CONFIG_VIDEO_OV2640 is not set
# CONFIG_VIDEO_OV2659 is not set
# CONFIG_VIDEO_OV2680 is not set
# CONFIG_VIDEO_OV2685 is not set
# CONFIG_VIDEO_OV2740 is not set
# CONFIG_VIDEO_OV5640 is not set
# CONFIG_VIDEO_OV5645 is not set
# CONFIG_VIDEO_OV5647 is not set
# CONFIG_VIDEO_OV6650 is not set
# CONFIG_VIDEO_OV5670 is not set
# CONFIG_VIDEO_OV5675 is not set
# CONFIG_VIDEO_OV5695 is not set
# CONFIG_VIDEO_OV7251 is not set
# CONFIG_VIDEO_OV772X is not set
# CONFIG_VIDEO_OV7640 is not set
# CONFIG_VIDEO_OV7670 is not set
# CONFIG_VIDEO_OV7740 is not set
# CONFIG_VIDEO_OV8856 is not set
# CONFIG_VIDEO_OV9640 is not set
# CONFIG_VIDEO_OV9650 is not set
# CONFIG_VIDEO_OV13858 is not set
# CONFIG_VIDEO_VS6624 is not set
# CONFIG_VIDEO_MT9M001 is not set
# CONFIG_VIDEO_MT9M032 is not set
# CONFIG_VIDEO_MT9M111 is not set
# CONFIG_VIDEO_MT9P031 is not set
# CONFIG_VIDEO_MT9T001 is not set
# CONFIG_VIDEO_MT9T112 is not set
# CONFIG_VIDEO_MT9V011 is not set
# CONFIG_VIDEO_MT9V032 is not set
# CONFIG_VIDEO_MT9V111 is not set
# CONFIG_VIDEO_SR030PC30 is not set
# CONFIG_VIDEO_NOON010PC30 is not set
# CONFIG_VIDEO_M5MOLS is not set
# CONFIG_VIDEO_RDACM20 is not set
# CONFIG_VIDEO_RJ54N1 is not set
# CONFIG_VIDEO_S5K6AA is not set
# CONFIG_VIDEO_S5K6A3 is not set
# CONFIG_VIDEO_S5K4ECGX is not set
# CONFIG_VIDEO_S5K5BAF is not set
# CONFIG_VIDEO_SMIAPP is not set
# CONFIG_VIDEO_ET8EK8 is not set
# CONFIG_VIDEO_S5C73M3 is not set

# end of Camera sensor devices

#
# Lens drivers
#
# CONFIG_VIDEO_AD5820 is not set
# CONFIG_VIDEO_AK7375 is not set
# CONFIG_VIDEO_DW9714 is not set
# CONFIG_VIDEO_DW9768 is not set
# CONFIG_VIDEO_DW9807_VCM is not set

# end of Lens drivers

#
# Flash devices
#
# CONFIG_VIDEO_ADP1653 is not set
# CONFIG_VIDEO_LM3560 is not set
# CONFIG_VIDEO_LM3646 is not set

# end of Flash devices

#
# SPI I2C drivers auto-selected by 'Autoselect ancillary drivers' #

#
# Media SPI Adapters
#
# CONFIG_CXD2880_SPI_DRV is not set

# end of Media SPI Adapters

CONFIG_MEDIA_TUNER=m

#
# Tuner drivers auto-selected by 'Autoselect ancillary drivers' #
CONFIG_MEDIA_TUNER_SIMPLE=m CONFIG_MEDIA_TUNER_TDA8290=m CONFIG_MEDIA_TUNER_TDA827X=m CONFIG_MEDIA_TUNER_TDA18271=m CONFIG_MEDIA_TUNER_TDA9887=m CONFIG_MEDIA_TUNER_MT20XX=m CONFIG_MEDIA_TUNER_XC2028=m CONFIG_MEDIA_TUNER_XC5000=m CONFIG_MEDIA_TUNER_XC4000=m CONFIG_MEDIA_TUNER_MC44S803=m

#
# DVB Frontend drivers auto-selected by 'Autoselect ancillary drivers' #

#
# Multistandard (satellite) frontends
#

#
# Multistandard (cable + terrestrial) frontends
#

#
# DVB-S (satellite) frontends
#

#
# DVB-T (terrestrial) frontends
#

#
# DVB-C (cable) frontends
#

#
# ATSC (North American/Korean Terrestrial/Cable DTV) frontends #

#
# ISDB-T (terrestrial) frontends
#

#
# ISDB-S (satellite) & ISDB-T (terrestrial) frontends #

#
# Digital terrestrial only tuners/PLL
#

#
# SEC control devices for DVB-S
#

#
# Common Interface (EN50221) controller drivers
#

# end of Media ancillary drivers

#
# Graphics support
#
CONFIG_VGA_ARB=y
CONFIG_VGA_ARB_MAX_GPUS=16
CONFIG_TEGRA_HOST1X=m
CONFIG_TEGRA_HOST1X_FIREWALL=y
CONFIG_DRM=m
CONFIG_DRM_MIPI_DSI=y
# CONFIG_DRM_DP_AUX_CHARDEV is not set
# CONFIG_DRM_DEBUG_SELFTEST is not set
CONFIG_DRM_KMS_HELPER=m
CONFIG_DRM_KMS_FB_HELPER=y
CONFIG_DRM_FBDEV_EMULATION=y
CONFIG_DRM_FBDEV_OVERALLOC=100
# CONFIG_DRM_LOAD_EDID_FIRMWARE is not set
# CONFIG_DRM_DP_CEC is not set
CONFIG_DRM_TTM=m
CONFIG_DRM_VRAM_HELPER=m
CONFIG_DRM_TTM_HELPER=m
CONFIG_DRM_GEM_CMA_HELPER=y
CONFIG_DRM_KMS_CMA_HELPER=y
CONFIG_DRM_GEM_SHMEM_HELPER=y
CONFIG_DRM_VM=y
CONFIG_DRM_SCHED=m

#
# I2C encoder or helper chips
#
CONFIG_DRM_I2C_CH7006=m
CONFIG_DRM_I2C_SIL164=m
CONFIG_DRM_I2C_NXP_TDA998X=m
# CONFIG_DRM_I2C_NXP_TDA9950 is not set

# end of I2C encoder or helper chips

#
# ARM devices
#
# CONFIG_DRM_HDLCD is not set
CONFIG_DRM_MALI_DISPLAY=m
# CONFIG_DRM_KOMEDA is not set

# end of ARM devices

# CONFIG_DRM_RADEON is not set
# CONFIG_DRM_AMDGPU is not set
CONFIG_DRM_NOUVEAU=m
CONFIG_NOUVEAU_LEGACY_CTX_SUPPORT=y
CONFIG_NOUVEAU_PLATFORM_DRIVER=y
CONFIG_NOUVEAU_DEBUG=5
CONFIG_NOUVEAU_DEBUG_DEFAULT=3
# CONFIG_NOUVEAU_DEBUG_MMU is not set
# CONFIG_NOUVEAU_DEBUG_PUSH is not set
CONFIG_DRM_NOUVEAU_BACKLIGHT=y
# CONFIG_DRM_KMB_DISPLAY is not set
# CONFIG_DRM_VGEM is not set
# CONFIG_DRM_VKMS is not set
CONFIG_DRM_EXYNOS=m

#
# CRTCs
#
# CONFIG_DRM_EXYNOS_FIMD is not set
CONFIG_DRM_EXYNOS5433_DECON=y
CONFIG_DRM_EXYNOS7_DECON=y
# CONFIG_DRM_EXYNOS_MIXER is not set
# CONFIG_DRM_EXYNOS_VIDI is not set

#
# Encoders and Bridges
#
CONFIG_DRM_EXYNOS_DSI=y
# CONFIG_DRM_EXYNOS_DP is not set
CONFIG_DRM_EXYNOS_HDMI=y
CONFIG_DRM_EXYNOS_MIC=y

#
# Sub-drivers
#
# CONFIG_DRM_EXYNOS_G2D is not set
# CONFIG_DRM_EXYNOS_FIMC is not set
# CONFIG_DRM_EXYNOS_ROTATOR is not set
# CONFIG_DRM_EXYNOS_SCALER is not set
CONFIG_DRM_ROCKCHIP=m
CONFIG_ROCKCHIP_ANALOGIX_DP=y
CONFIG_ROCKCHIP_CDN_DP=y
CONFIG_ROCKCHIP_DW_HDMI=y
CONFIG_ROCKCHIP_DW_MIPI_DSI=y
CONFIG_ROCKCHIP_INNO_HDMI=y
# CONFIG_ROCKCHIP_LVDS is not set
# CONFIG_ROCKCHIP_RGB is not set
# CONFIG_ROCKCHIP_RK3066_HDMI is not set
# CONFIG_DRM_UDL is not set
# CONFIG_DRM_AST is not set
# CONFIG_DRM_MGAG200 is not set
CONFIG_DRM_RCAR_DU=m
CONFIG_DRM_RCAR_CMM=m
CONFIG_DRM_RCAR_DW_HDMI=m
CONFIG_DRM_RCAR_LVDS=m
CONFIG_DRM_RCAR_VSP=y
CONFIG_DRM_RCAR_WRITEBACK=y
CONFIG_DRM_SUN4I=m
CONFIG_DRM_SUN4I_HDMI=m
# CONFIG_DRM_SUN4I_HDMI_CEC is not set
CONFIG_DRM_SUN4I_BACKEND=m
CONFIG_DRM_SUN6I_DSI=m
CONFIG_DRM_SUN8I_DW_HDMI=m
CONFIG_DRM_SUN8I_MIXER=m
CONFIG_DRM_SUN8I_TCON_TOP=m
# CONFIG_DRM_QXL is not set
# CONFIG_DRM_BOCHS is not set
CONFIG_DRM_VIRTIO_GPU=m
CONFIG_DRM_TEGRA=m
# CONFIG_DRM_TEGRA_DEBUG is not set
CONFIG_DRM_PANEL=y

#
# Display Panels
#
# CONFIG_DRM_PANEL_ARM_VERSATILE is not set
# CONFIG_DRM_PANEL_ASUS_Z00T_TM5P5_NT35596 is not set # CONFIG_DRM_PANEL_BOE_HIMAX8279D is not set
# CONFIG_DRM_PANEL_BOE_TV101WUM_NL6 is not set CONFIG_DRM_PANEL_LVDS=m CONFIG_DRM_PANEL_SIMPLE=m
# CONFIG_DRM_PANEL_ELIDA_KD35T133 is not set
# CONFIG_DRM_PANEL_FEIXIN_K101_IM2BA02 is not set # CONFIG_DRM_PANEL_FEIYANG_FY07024DI26A30D is not set # CONFIG_DRM_PANEL_ILITEK_IL9322 is not set
# CONFIG_DRM_PANEL_ILITEK_ILI9881C is not set
# CONFIG_DRM_PANEL_INNOLUX_P079ZCA is not set
# CONFIG_DRM_PANEL_JDI_LT070ME05000 is not set # CONFIG_DRM_PANEL_KINGDISPLAY_KD097D04 is not set # CONFIG_DRM_PANEL_LEADTEK_LTK050H3146W is not set # CONFIG_DRM_PANEL_LEADTEK_LTK500HD1829 is not set # CONFIG_DRM_PANEL_SAMSUNG_LD9040 is not set
# CONFIG_DRM_PANEL_LG_LB035Q02 is not set
# CONFIG_DRM_PANEL_LG_LG4573 is not set
# CONFIG_DRM_PANEL_NEC_NL8048HL11 is not set
# CONFIG_DRM_PANEL_NOVATEK_NT35510 is not set
# CONFIG_DRM_PANEL_NOVATEK_NT36672A is not set # CONFIG_DRM_PANEL_NOVATEK_NT39016 is not set
# CONFIG_DRM_PANEL_MANTIX_MLAF057WE51 is not set # CONFIG_DRM_PANEL_OLIMEX_LCD_OLINUXINO is not set # CONFIG_DRM_PANEL_ORISETECH_OTM8009A is not set # CONFIG_DRM_PANEL_OSD_OSD101T2587_53TS is not set # CONFIG_DRM_PANEL_PANASONIC_VVX10F034N00 is not set # CONFIG_DRM_PANEL_RASPBERRYPI_TOUCHSCREEN is not set # CONFIG_DRM_PANEL_RAYDIUM_RM67191 is not set
# CONFIG_DRM_PANEL_RAYDIUM_RM68200 is not set
# CONFIG_DRM_PANEL_RONBO_RB070D30 is not set
# CONFIG_DRM_PANEL_SAMSUNG_S6D16D0 is not set
# CONFIG_DRM_PANEL_SAMSUNG_S6E3HA2 is not set
# CONFIG_DRM_PANEL_SAMSUNG_S6E63J0X03 is not set # CONFIG_DRM_PANEL_SAMSUNG_S6E63M0 is not set
# CONFIG_DRM_PANEL_SAMSUNG_S6E88A0_AMS452EF01 is not set # CONFIG_DRM_PANEL_SAMSUNG_S6E8AA0 is not set
# CONFIG_DRM_PANEL_SEIKO_43WVF1G is not set
# CONFIG_DRM_PANEL_SHARP_LQ101R1SX01 is not set # CONFIG_DRM_PANEL_SHARP_LS037V7DW01 is not set # CONFIG_DRM_PANEL_SHARP_LS043T1LE01 is not set # CONFIG_DRM_PANEL_SITRONIX_ST7701 is not set
# CONFIG_DRM_PANEL_SITRONIX_ST7703 is not set
# CONFIG_DRM_PANEL_SITRONIX_ST7789V is not set # CONFIG_DRM_PANEL_SONY_ACX424AKP is not set
# CONFIG_DRM_PANEL_SONY_ACX565AKM is not set
# CONFIG_DRM_PANEL_TDO_TL070WSH30 is not set
# CONFIG_DRM_PANEL_TPO_TD028TTEC1 is not set
# CONFIG_DRM_PANEL_TPO_TD043MTEA1 is not set
# CONFIG_DRM_PANEL_TPO_TPG110 is not set CONFIG_DRM_PANEL_TRULY_NT35597_WQXGA=m
# CONFIG_DRM_PANEL_VISIONOX_RM69299 is not set # CONFIG_DRM_PANEL_XINPENG_XPP055C272 is not set

# end of Display Panels

CONFIG_DRM_BRIDGE=y
CONFIG_DRM_PANEL_BRIDGE=y

#
# Display Interface Bridges
#
# CONFIG_DRM_CDNS_DSI is not set
# CONFIG_DRM_CHRONTEL_CH7033 is not set CONFIG_DRM_DISPLAY_CONNECTOR=m
# CONFIG_DRM_LONTIUM_LT9611 is not set
# CONFIG_DRM_LONTIUM_LT9611UXC is not set
# CONFIG_DRM_LVDS_CODEC is not set
# CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW is not set # CONFIG_DRM_NWL_MIPI_DSI is not set
# CONFIG_DRM_NXP_PTN3460 is not set
# CONFIG_DRM_PARADE_PS8622 is not set
# CONFIG_DRM_PARADE_PS8640 is not set
# CONFIG_DRM_SIL_SII8620 is not set CONFIG_DRM_SII902X=m
# CONFIG_DRM_SII9234 is not set CONFIG_DRM_SIMPLE_BRIDGE=m CONFIG_DRM_THINE_THC63LVD1024=m
# CONFIG_DRM_TOSHIBA_TC358762 is not set
# CONFIG_DRM_TOSHIBA_TC358764 is not set
# CONFIG_DRM_TOSHIBA_TC358767 is not set
# CONFIG_DRM_TOSHIBA_TC358768 is not set
# CONFIG_DRM_TOSHIBA_TC358775 is not set
# CONFIG_DRM_TI_TFP410 is not set CONFIG_DRM_TI_SN65DSI86=m
# CONFIG_DRM_TI_TPD12S015 is not set
# CONFIG_DRM_ANALOGIX_ANX6345 is not set
# CONFIG_DRM_ANALOGIX_ANX78XX is not set CONFIG_DRM_ANALOGIX_DP=m
# CONFIG_DRM_ANALOGIX_ANX7625 is not set CONFIG_DRM_I2C_ADV7511=m
# CONFIG_DRM_I2C_ADV7511_AUDIO is not set CONFIG_DRM_I2C_ADV7511_CEC=y
# CONFIG_DRM_CDNS_MHDP8546 is not set CONFIG_DRM_DW_HDMI=m CONFIG_DRM_DW_HDMI_AHB_AUDIO=m CONFIG_DRM_DW_HDMI_I2S_AUDIO=m CONFIG_DRM_DW_HDMI_CEC=m CONFIG_DRM_DW_MIPI_DSI=m

# end of Display Interface Bridges

# CONFIG_DRM_IMX_DCSS is not set
CONFIG_DRM_VC4=m
# CONFIG_DRM_VC4_HDMI_CEC is not set
CONFIG_DRM_ETNAVIV=m
CONFIG_DRM_ETNAVIV_THERMAL=y
# CONFIG_DRM_ARCPGU is not set
CONFIG_DRM_HISI_HIBMC=m
CONFIG_DRM_HISI_KIRIN=m
# CONFIG_DRM_MEDIATEK is not set
# CONFIG_DRM_ZTE is not set
# CONFIG_DRM_MXSFB is not set
CONFIG_DRM_MESON=m
CONFIG_DRM_MESON_DW_HDMI=m
# CONFIG_DRM_CIRRUS_QEMU is not set
# CONFIG_DRM_GM12U320 is not set
# CONFIG_TINYDRM_HX8357D is not set
# CONFIG_TINYDRM_ILI9225 is not set
# CONFIG_TINYDRM_ILI9341 is not set
# CONFIG_TINYDRM_ILI9486 is not set
# CONFIG_TINYDRM_MI0283QT is not set
# CONFIG_TINYDRM_REPAPER is not set
# CONFIG_TINYDRM_ST7586 is not set
# CONFIG_TINYDRM_ST7735R is not set
CONFIG_DRM_PL111=m
# CONFIG_DRM_XEN is not set
CONFIG_DRM_LIMA=m
CONFIG_DRM_PANFROST=m
# CONFIG_DRM_TIDSS is not set
# CONFIG_DRM_ZYNQMP_DPSUB is not set
CONFIG_DRM_LEGACY=y
# CONFIG_DRM_TDFX is not set
# CONFIG_DRM_R128 is not set
# CONFIG_DRM_MGA is not set
# CONFIG_DRM_VIA is not set
# CONFIG_DRM_SAVAGE is not set
CONFIG_DRM_PANEL_ORIENTATION_QUIRKS=y

#
# Frame buffer Devices
#
CONFIG_FB_CMDLINE=y
CONFIG_FB_NOTIFY=y
CONFIG_FB=y
# CONFIG_FIRMWARE_EDID is not set
CONFIG_FB_CFB_FILLRECT=y
CONFIG_FB_CFB_COPYAREA=y
CONFIG_FB_CFB_IMAGEBLIT=y
CONFIG_FB_SYS_FILLRECT=y
CONFIG_FB_SYS_COPYAREA=y
CONFIG_FB_SYS_IMAGEBLIT=y
# CONFIG_FB_FOREIGN_ENDIAN is not set
CONFIG_FB_SYS_FOPS=y
CONFIG_FB_DEFERRED_IO=y
CONFIG_FB_MODE_HELPERS=y
# CONFIG_FB_TILEBLITTING is not set

#
# Frame buffer hardware drivers
#
# CONFIG_FB_CIRRUS is not set
# CONFIG_FB_PM2 is not set
# CONFIG_FB_ARMCLCD is not set
# CONFIG_FB_IMX is not set
# CONFIG_FB_CYBER2000 is not set
# CONFIG_FB_ASILIANT is not set
# CONFIG_FB_IMSTT is not set
CONFIG_FB_EFI=y
# CONFIG_FB_OPENCORES is not set
# CONFIG_FB_S1D13XXX is not set
# CONFIG_FB_NVIDIA is not set
# CONFIG_FB_RIVA is not set
# CONFIG_FB_I740 is not set
# CONFIG_FB_MATROX is not set
# CONFIG_FB_RADEON is not set
# CONFIG_FB_ATY128 is not set
# CONFIG_FB_ATY is not set
# CONFIG_FB_S3 is not set
# CONFIG_FB_SAVAGE is not set
# CONFIG_FB_SIS is not set
# CONFIG_FB_NEOMAGIC is not set
# CONFIG_FB_KYRO is not set
# CONFIG_FB_3DFX is not set
# CONFIG_FB_VOODOO1 is not set
# CONFIG_FB_VT8623 is not set
# CONFIG_FB_TRIDENT is not set
# CONFIG_FB_ARK is not set
# CONFIG_FB_PM3 is not set
# CONFIG_FB_CARMINE is not set
# CONFIG_FB_SH_MOBILE_LCDC is not set
# CONFIG_FB_SMSCUFX is not set
# CONFIG_FB_UDL is not set
# CONFIG_FB_IBM_GXT4500 is not set
# CONFIG_FB_XILINX is not set
# CONFIG_FB_VIRTUAL is not set
CONFIG_XEN_FBDEV_FRONTEND=y
# CONFIG_FB_METRONOME is not set
# CONFIG_FB_MB862XX is not set
CONFIG_FB_MX3=y
# CONFIG_FB_SIMPLE is not set
# CONFIG_FB_SSD1307 is not set
# CONFIG_FB_SM712 is not set

# end of Frame buffer Devices

#
# Backlight & LCD device support
#
# CONFIG_LCD_CLASS_DEVICE is not set
CONFIG_BACKLIGHT_CLASS_DEVICE=y
# CONFIG_BACKLIGHT_KTD253 is not set
CONFIG_BACKLIGHT_PWM=m
# CONFIG_BACKLIGHT_QCOM_WLED is not set
# CONFIG_BACKLIGHT_ADP8860 is not set
# CONFIG_BACKLIGHT_ADP8870 is not set
# CONFIG_BACKLIGHT_LM3630A is not set
# CONFIG_BACKLIGHT_LM3639 is not set
CONFIG_BACKLIGHT_LP855X=m
# CONFIG_BACKLIGHT_GPIO is not set
# CONFIG_BACKLIGHT_LV5207LP is not set
# CONFIG_BACKLIGHT_BD6107 is not set
# CONFIG_BACKLIGHT_ARCXCNN is not set
# CONFIG_BACKLIGHT_LED is not set

# end of Backlight & LCD device support

CONFIG_VIDEOMODE_HELPERS=y
CONFIG_HDMI=y

#
# Console display driver support
#
CONFIG_DUMMY_CONSOLE=y CONFIG_DUMMY_CONSOLE_COLUMNS=80 CONFIG_DUMMY_CONSOLE_ROWS=25 CONFIG_FRAMEBUFFER_CONSOLE=y CONFIG_FRAMEBUFFER_CONSOLE_DETECT_PRIMARY=y
# CONFIG_FRAMEBUFFER_CONSOLE_ROTATION is not set # CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER is not set

# end of Console display driver support

CONFIG_LOGO=y
# CONFIG_LOGO_LINUX_MONO is not set
# CONFIG_LOGO_LINUX_VGA16 is not set
CONFIG_LOGO_LINUX_CLUT224=y

# end of Graphics support

CONFIG_SOUND=y
CONFIG_SND=y
CONFIG_SND_TIMER=y
CONFIG_SND_PCM=y
CONFIG_SND_PCM_ELD=y
CONFIG_SND_PCM_IEC958=y
CONFIG_SND_DMAENGINE_PCM=y
CONFIG_SND_JACK=y
CONFIG_SND_JACK_INPUT_DEV=y
# CONFIG_SND_OSSEMUL is not set
CONFIG_SND_PCM_TIMER=y
# CONFIG_SND_HRTIMER is not set
CONFIG_SND_DYNAMIC_MINORS=y
CONFIG_SND_MAX_CARDS=32
CONFIG_SND_SUPPORT_OLD_API=y
CONFIG_SND_PROC_FS=y
CONFIG_SND_VERBOSE_PROCFS=y
# CONFIG_SND_VERBOSE_PRINTK is not set
# CONFIG_SND_DEBUG is not set
CONFIG_SND_VMASTER=y
# CONFIG_SND_SEQUENCER is not set
CONFIG_SND_DRIVERS=y
# CONFIG_SND_DUMMY is not set
# CONFIG_SND_ALOOP is not set
# CONFIG_SND_MTPAV is not set
# CONFIG_SND_SERIAL_U16550 is not set
# CONFIG_SND_MPU401 is not set
CONFIG_SND_PCI=y
# CONFIG_SND_AD1889 is not set
# CONFIG_SND_ALS300 is not set
# CONFIG_SND_ALI5451 is not set
# CONFIG_SND_ATIIXP is not set
# CONFIG_SND_ATIIXP_MODEM is not set
# CONFIG_SND_AU8810 is not set
# CONFIG_SND_AU8820 is not set
# CONFIG_SND_AU8830 is not set
# CONFIG_SND_AW2 is not set
# CONFIG_SND_AZT3328 is not set
# CONFIG_SND_BT87X is not set
# CONFIG_SND_CA0106 is not set
# CONFIG_SND_CMIPCI is not set
# CONFIG_SND_OXYGEN is not set
# CONFIG_SND_CS4281 is not set
# CONFIG_SND_CS46XX is not set
# CONFIG_SND_CTXFI is not set
# CONFIG_SND_DARLA20 is not set
# CONFIG_SND_GINA20 is not set
# CONFIG_SND_LAYLA20 is not set
# CONFIG_SND_DARLA24 is not set
# CONFIG_SND_GINA24 is not set
# CONFIG_SND_LAYLA24 is not set
# CONFIG_SND_MONA is not set
# CONFIG_SND_MIA is not set
# CONFIG_SND_ECHO3G is not set
# CONFIG_SND_INDIGO is not set
# CONFIG_SND_INDIGOIO is not set
# CONFIG_SND_INDIGODJ is not set
# CONFIG_SND_INDIGOIOX is not set
# CONFIG_SND_INDIGODJX is not set
# CONFIG_SND_EMU10K1 is not set
# CONFIG_SND_EMU10K1X is not set
# CONFIG_SND_ENS1370 is not set
# CONFIG_SND_ENS1371 is not set
# CONFIG_SND_ES1938 is not set
# CONFIG_SND_ES1968 is not set
# CONFIG_SND_FM801 is not set
# CONFIG_SND_HDSP is not set
# CONFIG_SND_HDSPM is not set
# CONFIG_SND_ICE1712 is not set
# CONFIG_SND_ICE1724 is not set
# CONFIG_SND_INTEL8X0 is not set
# CONFIG_SND_INTEL8X0M is not set
# CONFIG_SND_KORG1212 is not set
# CONFIG_SND_LOLA is not set
# CONFIG_SND_LX6464ES is not set
# CONFIG_SND_MAESTRO3 is not set
# CONFIG_SND_MIXART is not set
# CONFIG_SND_NM256 is not set
# CONFIG_SND_PCXHR is not set
# CONFIG_SND_RIPTIDE is not set
# CONFIG_SND_RME32 is not set
# CONFIG_SND_RME96 is not set
# CONFIG_SND_RME9652 is not set
# CONFIG_SND_SE6X is not set
# CONFIG_SND_SONICVIBES is not set
# CONFIG_SND_TRIDENT is not set
# CONFIG_SND_VIA82XX is not set
# CONFIG_SND_VIA82XX_MODEM is not set
# CONFIG_SND_VIRTUOSO is not set
# CONFIG_SND_VX222 is not set
# CONFIG_SND_YMFPCI is not set

#
# HD-Audio
#
CONFIG_SND_HDA=m
# CONFIG_SND_HDA_INTEL is not set
CONFIG_SND_HDA_TEGRA=m
# CONFIG_SND_HDA_HWDEP is not set
# CONFIG_SND_HDA_RECONFIG is not set
# CONFIG_SND_HDA_INPUT_BEEP is not set
# CONFIG_SND_HDA_PATCH_LOADER is not set
# CONFIG_SND_HDA_CODEC_REALTEK is not set
# CONFIG_SND_HDA_CODEC_ANALOG is not set
# CONFIG_SND_HDA_CODEC_SIGMATEL is not set
# CONFIG_SND_HDA_CODEC_VIA is not set
CONFIG_SND_HDA_CODEC_HDMI=m
# CONFIG_SND_HDA_CODEC_CIRRUS is not set
# CONFIG_SND_HDA_CODEC_CONEXANT is not set
# CONFIG_SND_HDA_CODEC_CA0110 is not set
# CONFIG_SND_HDA_CODEC_CA0132 is not set
# CONFIG_SND_HDA_CODEC_CMEDIA is not set
# CONFIG_SND_HDA_CODEC_SI3054 is not set
# CONFIG_SND_HDA_GENERIC is not set
CONFIG_SND_HDA_POWER_SAVE_DEFAULT=0

# end of HD-Audio

CONFIG_SND_HDA_CORE=m
CONFIG_SND_HDA_ALIGNED_MMIO=y
CONFIG_SND_HDA_COMPONENT=y
CONFIG_SND_HDA_PREALLOC_SIZE=64
CONFIG_SND_SPI=y
CONFIG_SND_USB=y
# CONFIG_SND_USB_AUDIO is not set
# CONFIG_SND_USB_UA101 is not set
# CONFIG_SND_USB_CAIAQ is not set
# CONFIG_SND_USB_6FIRE is not set
# CONFIG_SND_USB_HIFACE is not set
# CONFIG_SND_BCD2000 is not set
# CONFIG_SND_USB_POD is not set
# CONFIG_SND_USB_PODHD is not set
# CONFIG_SND_USB_TONEPORT is not set
# CONFIG_SND_USB_VARIAX is not set
CONFIG_SND_SOC=y
CONFIG_SND_SOC_GENERIC_DMAENGINE_PCM=y
# CONFIG_SND_SOC_AMD_ACP is not set
# CONFIG_SND_ATMEL_SOC is not set
CONFIG_SND_BCM2835_SOC_I2S=m
# CONFIG_SND_BCM63XX_I2S_WHISTLER is not set
# CONFIG_SND_DESIGNWARE_I2S is not set

#
# SoC Audio for Freescale CPUs
#

#
# Common SoC Audio options for Freescale CPUs:
#
# CONFIG_SND_SOC_FSL_ASRC is not set
# CONFIG_SND_SOC_FSL_SAI is not set
# CONFIG_SND_SOC_FSL_AUDMIX is not set
# CONFIG_SND_SOC_FSL_SSI is not set
# CONFIG_SND_SOC_FSL_SPDIF is not set
# CONFIG_SND_SOC_FSL_ESAI is not set
# CONFIG_SND_SOC_FSL_MICFIL is not set
# CONFIG_SND_SOC_FSL_XCVR is not set
# CONFIG_SND_SOC_FSL_AUD2HTX is not set
# CONFIG_SND_SOC_IMX_AUDMUX is not set
# CONFIG_SND_IMX_SOC is not set

# end of SoC Audio for Freescale CPUs

# CONFIG_SND_I2S_HI6210_I2S is not set
# CONFIG_SND_KIRKWOOD_SOC is not set
# CONFIG_SND_SOC_IMG is not set
# CONFIG_SND_SOC_INTEL_KEEMBAY is not set
# CONFIG_SND_SOC_MT2701 is not set
# CONFIG_SND_SOC_MT6797 is not set
# CONFIG_SND_SOC_MT8173 is not set
# CONFIG_SND_SOC_MT8183 is not set
# CONFIG_SND_SOC_MTK_BTCVSD is not set
# CONFIG_SND_SOC_MT8192 is not set

#
# ASoC support for Amlogic platforms
#
CONFIG_SND_MESON_AIU=m
CONFIG_SND_MESON_AXG_FIFO=m
CONFIG_SND_MESON_AXG_FRDDR=m
CONFIG_SND_MESON_AXG_TODDR=m
CONFIG_SND_MESON_AXG_TDM_FORMATTER=m
CONFIG_SND_MESON_AXG_TDM_INTERFACE=m
CONFIG_SND_MESON_AXG_TDMIN=m
CONFIG_SND_MESON_AXG_TDMOUT=m
CONFIG_SND_MESON_AXG_SOUND_CARD=m
CONFIG_SND_MESON_AXG_SPDIFOUT=m
CONFIG_SND_MESON_AXG_SPDIFIN=m
CONFIG_SND_MESON_AXG_PDM=m
CONFIG_SND_MESON_CARD_UTILS=m
CONFIG_SND_MESON_CODEC_GLUE=m
CONFIG_SND_MESON_GX_SOUND_CARD=m
# CONFIG_SND_MESON_G12A_TOACODEC is not set
CONFIG_SND_MESON_G12A_TOHDMITX=m
CONFIG_SND_SOC_MESON_T9015=m

# end of ASoC support for Amlogic platforms

# CONFIG_SND_SOC_QCOM is not set
CONFIG_SND_SOC_ROCKCHIP=m
CONFIG_SND_SOC_ROCKCHIP_I2S=m
# CONFIG_SND_SOC_ROCKCHIP_PDM is not set
CONFIG_SND_SOC_ROCKCHIP_SPDIF=m
# CONFIG_SND_SOC_ROCKCHIP_MAX98090 is not set
CONFIG_SND_SOC_ROCKCHIP_RT5645=m
# CONFIG_SND_SOC_RK3288_HDMI_ANALOG is not set
CONFIG_SND_SOC_RK3399_GRU_SOUND=m
CONFIG_SND_SOC_SAMSUNG=y
# CONFIG_SND_SAMSUNG_PCM is not set
# CONFIG_SND_SAMSUNG_SPDIF is not set
# CONFIG_SND_SAMSUNG_I2S is not set
# CONFIG_SND_SOC_SAMSUNG_SMDK_WM8994 is not set
# CONFIG_SND_SOC_SAMSUNG_SMDK_SPDIF is not set
# CONFIG_SND_SOC_SMDK_WM8994_PCM is not set
# CONFIG_SND_SOC_SNOW is not set
# CONFIG_SND_SOC_ODROID is not set
# CONFIG_SND_SOC_ARNDALE is not set
# CONFIG_SND_SOC_SAMSUNG_MIDAS_WM1811 is not set

#
# SoC Audio support for Renesas SoCs
#
# CONFIG_SND_SOC_SH4_FSI is not set
CONFIG_SND_SOC_RCAR=m

# end of SoC Audio support for Renesas SoCs

# CONFIG_SND_SOC_SOF_TOPLEVEL is not set
# CONFIG_SND_SOC_SPRD is not set

#
# STMicroelectronics STM32 SOC audio support
#

# end of STMicroelectronics STM32 SOC audio support

#
# Allwinner SoC Audio support
#
# CONFIG_SND_SUN4I_CODEC is not set
# CONFIG_SND_SUN8I_CODEC is not set
# CONFIG_SND_SUN8I_CODEC_ANALOG is not set
# CONFIG_SND_SUN50I_CODEC_ANALOG is not set
# CONFIG_SND_SUN4I_I2S is not set
CONFIG_SND_SUN4I_SPDIF=m

# end of Allwinner SoC Audio support

# CONFIG_SND_SOC_TEGRA is not set

#
# Audio support for Texas Instruments SoCs
#

#
# Texas Instruments DAI support for:
#
# CONFIG_SND_SOC_DAVINCI_MCASP is not set

#
# Audio support for boards with Texas Instruments SoCs #
# CONFIG_SND_SOC_J721E_EVM is not set

# end of Audio support for Texas Instruments SoCs

# CONFIG_SND_SOC_UNIPHIER is not set
# CONFIG_SND_SOC_XILINX_I2S is not set
# CONFIG_SND_SOC_XILINX_AUDIO_FORMATTER is not set # CONFIG_SND_SOC_XILINX_SPDIF is not set
# CONFIG_SND_SOC_XTFPGA_I2S is not set
# CONFIG_ZX_SPDIF is not set
# CONFIG_ZX_I2S is not set
# CONFIG_ZX_TDM is not set CONFIG_SND_SOC_I2C_AND_SPI=y

#
# CODEC drivers
#
# CONFIG_SND_SOC_AC97_CODEC is not set
# CONFIG_SND_SOC_ADAU1701 is not set
# CONFIG_SND_SOC_ADAU1761_I2C is not set
# CONFIG_SND_SOC_ADAU1761_SPI is not set
# CONFIG_SND_SOC_ADAU7002 is not set
# CONFIG_SND_SOC_ADAU7118_HW is not set
# CONFIG_SND_SOC_ADAU7118_I2C is not set
# CONFIG_SND_SOC_AK4104 is not set
# CONFIG_SND_SOC_AK4118 is not set
# CONFIG_SND_SOC_AK4458 is not set
# CONFIG_SND_SOC_AK4554 is not set
CONFIG_SND_SOC_AK4613=m
# CONFIG_SND_SOC_AK4642 is not set
# CONFIG_SND_SOC_AK5386 is not set
# CONFIG_SND_SOC_AK5558 is not set
# CONFIG_SND_SOC_ALC5623 is not set
# CONFIG_SND_SOC_BD28623 is not set
# CONFIG_SND_SOC_BT_SCO is not set
CONFIG_SND_SOC_CROS_EC_CODEC=m
# CONFIG_SND_SOC_CS35L32 is not set
# CONFIG_SND_SOC_CS35L33 is not set
# CONFIG_SND_SOC_CS35L34 is not set
# CONFIG_SND_SOC_CS35L35 is not set
# CONFIG_SND_SOC_CS35L36 is not set
# CONFIG_SND_SOC_CS42L42 is not set
# CONFIG_SND_SOC_CS42L51_I2C is not set
# CONFIG_SND_SOC_CS42L52 is not set
# CONFIG_SND_SOC_CS42L56 is not set
# CONFIG_SND_SOC_CS42L73 is not set
# CONFIG_SND_SOC_CS4234 is not set
# CONFIG_SND_SOC_CS4265 is not set
# CONFIG_SND_SOC_CS4270 is not set
# CONFIG_SND_SOC_CS4271_I2C is not set
# CONFIG_SND_SOC_CS4271_SPI is not set
# CONFIG_SND_SOC_CS42XX8_I2C is not set
# CONFIG_SND_SOC_CS43130 is not set
# CONFIG_SND_SOC_CS4341 is not set
# CONFIG_SND_SOC_CS4349 is not set
# CONFIG_SND_SOC_CS53L30 is not set
# CONFIG_SND_SOC_CX2072X is not set
# CONFIG_SND_SOC_DA7213 is not set
CONFIG_SND_SOC_DA7219=m
CONFIG_SND_SOC_DMIC=m
CONFIG_SND_SOC_HDMI_CODEC=m
CONFIG_SND_SOC_ES7134=m
CONFIG_SND_SOC_ES7241=m
# CONFIG_SND_SOC_ES8316 is not set
# CONFIG_SND_SOC_ES8328_I2C is not set
# CONFIG_SND_SOC_ES8328_SPI is not set
# CONFIG_SND_SOC_GTM601 is not set
# CONFIG_SND_SOC_INNO_RK3036 is not set
# CONFIG_SND_SOC_MAX98088 is not set
CONFIG_SND_SOC_MAX98357A=m
# CONFIG_SND_SOC_MAX98504 is not set
# CONFIG_SND_SOC_MAX9867 is not set
CONFIG_SND_SOC_MAX98927=m
# CONFIG_SND_SOC_MAX98373_I2C is not set
# CONFIG_SND_SOC_MAX98373_SDW is not set
# CONFIG_SND_SOC_MAX98390 is not set
# CONFIG_SND_SOC_MAX9860 is not set
# CONFIG_SND_SOC_MSM8916_WCD_ANALOG is not set
# CONFIG_SND_SOC_MSM8916_WCD_DIGITAL is not set
# CONFIG_SND_SOC_PCM1681 is not set
# CONFIG_SND_SOC_PCM1789_I2C is not set
# CONFIG_SND_SOC_PCM179X_I2C is not set
# CONFIG_SND_SOC_PCM179X_SPI is not set
# CONFIG_SND_SOC_PCM186X_I2C is not set
# CONFIG_SND_SOC_PCM186X_SPI is not set
# CONFIG_SND_SOC_PCM3060_I2C is not set
# CONFIG_SND_SOC_PCM3060_SPI is not set
CONFIG_SND_SOC_PCM3168A=m
CONFIG_SND_SOC_PCM3168A_I2C=m
# CONFIG_SND_SOC_PCM3168A_SPI is not set
# CONFIG_SND_SOC_PCM5102A is not set
# CONFIG_SND_SOC_PCM512x_I2C is not set
# CONFIG_SND_SOC_PCM512x_SPI is not set
# CONFIG_SND_SOC_RK3328 is not set
CONFIG_SND_SOC_RL6231=m
# CONFIG_SND_SOC_RT1308_SDW is not set
CONFIG_SND_SOC_RT5514=m
CONFIG_SND_SOC_RT5514_SPI=m
# CONFIG_SND_SOC_RT5616 is not set
# CONFIG_SND_SOC_RT5631 is not set
CONFIG_SND_SOC_RT5645=m
# CONFIG_SND_SOC_RT5682_SDW is not set
# CONFIG_SND_SOC_RT700_SDW is not set
# CONFIG_SND_SOC_RT711_SDW is not set
# CONFIG_SND_SOC_RT715_SDW is not set
# CONFIG_SND_SOC_SGTL5000 is not set
CONFIG_SND_SOC_SIMPLE_AMPLIFIER=m
# CONFIG_SND_SOC_SIRF_AUDIO_CODEC is not set
CONFIG_SND_SOC_SPDIF=m
# CONFIG_SND_SOC_SSM2305 is not set
# CONFIG_SND_SOC_SSM2602_SPI is not set
# CONFIG_SND_SOC_SSM2602_I2C is not set
# CONFIG_SND_SOC_SSM4567 is not set
# CONFIG_SND_SOC_STA32X is not set
# CONFIG_SND_SOC_STA350 is not set
# CONFIG_SND_SOC_STI_SAS is not set
# CONFIG_SND_SOC_TAS2552 is not set
# CONFIG_SND_SOC_TAS2562 is not set
# CONFIG_SND_SOC_TAS2764 is not set
# CONFIG_SND_SOC_TAS2770 is not set
# CONFIG_SND_SOC_TAS5086 is not set
CONFIG_SND_SOC_TAS571X=m
# CONFIG_SND_SOC_TAS5720 is not set
# CONFIG_SND_SOC_TAS6424 is not set
# CONFIG_SND_SOC_TDA7419 is not set
# CONFIG_SND_SOC_TFA9879 is not set
# CONFIG_SND_SOC_TLV320AIC23_I2C is not set
# CONFIG_SND_SOC_TLV320AIC23_SPI is not set
# CONFIG_SND_SOC_TLV320AIC31XX is not set
# CONFIG_SND_SOC_TLV320AIC32X4_I2C is not set
# CONFIG_SND_SOC_TLV320AIC32X4_SPI is not set
# CONFIG_SND_SOC_TLV320AIC3X is not set
# CONFIG_SND_SOC_TLV320ADCX140 is not set
# CONFIG_SND_SOC_TS3A227E is not set
# CONFIG_SND_SOC_TSCS42XX is not set
# CONFIG_SND_SOC_TSCS454 is not set
# CONFIG_SND_SOC_UDA1334 is not set
# CONFIG_SND_SOC_WCD9335 is not set
CONFIG_SND_SOC_WCD934X=m
# CONFIG_SND_SOC_WM8510 is not set
# CONFIG_SND_SOC_WM8523 is not set
# CONFIG_SND_SOC_WM8524 is not set
# CONFIG_SND_SOC_WM8580 is not set
# CONFIG_SND_SOC_WM8711 is not set
# CONFIG_SND_SOC_WM8728 is not set
# CONFIG_SND_SOC_WM8731 is not set
# CONFIG_SND_SOC_WM8737 is not set
# CONFIG_SND_SOC_WM8741 is not set
# CONFIG_SND_SOC_WM8750 is not set
# CONFIG_SND_SOC_WM8753 is not set
# CONFIG_SND_SOC_WM8770 is not set
# CONFIG_SND_SOC_WM8776 is not set
# CONFIG_SND_SOC_WM8782 is not set
# CONFIG_SND_SOC_WM8804_I2C is not set
# CONFIG_SND_SOC_WM8804_SPI is not set
# CONFIG_SND_SOC_WM8903 is not set
# CONFIG_SND_SOC_WM8904 is not set
# CONFIG_SND_SOC_WM8960 is not set
# CONFIG_SND_SOC_WM8962 is not set
# CONFIG_SND_SOC_WM8974 is not set
# CONFIG_SND_SOC_WM8978 is not set
# CONFIG_SND_SOC_WM8985 is not set
CONFIG_SND_SOC_WSA881X=m
# CONFIG_SND_SOC_ZL38060 is not set
# CONFIG_SND_SOC_ZX_AUD96P22 is not set
# CONFIG_SND_SOC_MAX9759 is not set
# CONFIG_SND_SOC_MT6351 is not set
# CONFIG_SND_SOC_MT6358 is not set
# CONFIG_SND_SOC_MT6660 is not set
# CONFIG_SND_SOC_NAU8540 is not set
# CONFIG_SND_SOC_NAU8810 is not set
# CONFIG_SND_SOC_NAU8822 is not set
# CONFIG_SND_SOC_NAU8824 is not set
# CONFIG_SND_SOC_TPA6130A2 is not set

# end of CODEC drivers

CONFIG_SND_SIMPLE_CARD_UTILS=m
CONFIG_SND_SIMPLE_CARD=m
CONFIG_SND_AUDIO_GRAPH_CARD=m
# CONFIG_SND_XEN_FRONTEND is not set

#
# HID support
#
CONFIG_HID=y
# CONFIG_HID_BATTERY_STRENGTH is not set
# CONFIG_HIDRAW is not set
# CONFIG_UHID is not set
CONFIG_HID_GENERIC=y

#
# Special HID drivers
#
CONFIG_HID_A4TECH=y
# CONFIG_HID_ACCUTOUCH is not set
# CONFIG_HID_ACRUX is not set
CONFIG_HID_APPLE=y
# CONFIG_HID_APPLEIR is not set
# CONFIG_HID_ASUS is not set
# CONFIG_HID_AUREAL is not set
CONFIG_HID_BELKIN=y
# CONFIG_HID_BETOP_FF is not set
# CONFIG_HID_BIGBEN_FF is not set
CONFIG_HID_CHERRY=y
CONFIG_HID_CHICONY=y
# CONFIG_HID_CORSAIR is not set
# CONFIG_HID_COUGAR is not set
# CONFIG_HID_MACALLY is not set
# CONFIG_HID_PRODIKEYS is not set
# CONFIG_HID_CMEDIA is not set
# CONFIG_HID_CREATIVE_SB0540 is not set
CONFIG_HID_CYPRESS=y
# CONFIG_HID_DRAGONRISE is not set
# CONFIG_HID_EMS_FF is not set
# CONFIG_HID_ELAN is not set
# CONFIG_HID_ELECOM is not set
# CONFIG_HID_ELO is not set
CONFIG_HID_EZKEY=y
# CONFIG_HID_GEMBIRD is not set
# CONFIG_HID_GFRM is not set
# CONFIG_HID_GLORIOUS is not set
# CONFIG_HID_HOLTEK is not set
# CONFIG_HID_GOOGLE_HAMMER is not set
# CONFIG_HID_VIVALDI is not set
# CONFIG_HID_GT683R is not set
# CONFIG_HID_KEYTOUCH is not set
# CONFIG_HID_KYE is not set
# CONFIG_HID_UCLOGIC is not set
# CONFIG_HID_WALTOP is not set
# CONFIG_HID_VIEWSONIC is not set
# CONFIG_HID_GYRATION is not set
# CONFIG_HID_ICADE is not set
CONFIG_HID_ITE=y
# CONFIG_HID_JABRA is not set
# CONFIG_HID_TWINHAN is not set
CONFIG_HID_KENSINGTON=y
# CONFIG_HID_LCPOWER is not set
# CONFIG_HID_LED is not set
# CONFIG_HID_LENOVO is not set
CONFIG_HID_LOGITECH=y
# CONFIG_HID_LOGITECH_HIDPP is not set
# CONFIG_LOGITECH_FF is not set
# CONFIG_LOGIRUMBLEPAD2_FF is not set
# CONFIG_LOGIG940_FF is not set
# CONFIG_LOGIWHEELS_FF is not set
# CONFIG_HID_MAGICMOUSE is not set
# CONFIG_HID_MALTRON is not set
# CONFIG_HID_MAYFLASH is not set
CONFIG_HID_REDRAGON=y
CONFIG_HID_MICROSOFT=y
CONFIG_HID_MONTEREY=y
# CONFIG_HID_MULTITOUCH is not set
# CONFIG_HID_NTI is not set
# CONFIG_HID_NTRIG is not set
# CONFIG_HID_ORTEK is not set
# CONFIG_HID_PANTHERLORD is not set
# CONFIG_HID_PENMOUNT is not set
# CONFIG_HID_PETALYNX is not set
# CONFIG_HID_PICOLCD is not set
# CONFIG_HID_PLANTRONICS is not set
# CONFIG_HID_PRIMAX is not set
# CONFIG_HID_RETRODE is not set
# CONFIG_HID_ROCCAT is not set
# CONFIG_HID_SAITEK is not set
# CONFIG_HID_SAMSUNG is not set
# CONFIG_HID_SONY is not set
# CONFIG_HID_SPEEDLINK is not set
# CONFIG_HID_STEAM is not set
# CONFIG_HID_STEELSERIES is not set
# CONFIG_HID_SUNPLUS is not set
# CONFIG_HID_RMI is not set
# CONFIG_HID_GREENASIA is not set
# CONFIG_HID_SMARTJOYPLUS is not set
# CONFIG_HID_TIVO is not set
# CONFIG_HID_TOPSEED is not set
# CONFIG_HID_THINGM is not set
# CONFIG_HID_THRUSTMASTER is not set
# CONFIG_HID_UDRAW_PS3 is not set
# CONFIG_HID_U2FZERO is not set
# CONFIG_HID_WACOM is not set
# CONFIG_HID_WIIMOTE is not set
# CONFIG_HID_XINMO is not set
# CONFIG_HID_ZEROPLUS is not set
# CONFIG_HID_ZYDACRON is not set
# CONFIG_HID_SENSOR_HUB is not set
# CONFIG_HID_ALPS is not set
# CONFIG_HID_MCP2221 is not set

# end of Special HID drivers

#
# USB HID support
#
CONFIG_USB_HID=y
# CONFIG_HID_PID is not set
# CONFIG_USB_HIDDEV is not set

# end of USB HID support

#
# I2C HID support
#
CONFIG_I2C_HID=m

# end of I2C HID support
# end of HID support

CONFIG_USB_OHCI_LITTLE_ENDIAN=y
CONFIG_USB_SUPPORT=y
CONFIG_USB_COMMON=y
# CONFIG_USB_LED_TRIG is not set
CONFIG_USB_ULPI_BUS=y
CONFIG_USB_CONN_GPIO=y
CONFIG_USB_ARCH_HAS_HCD=y
CONFIG_USB=y
CONFIG_USB_PCI=y
# CONFIG_USB_ANNOUNCE_NEW_DEVICES is not set

#
# Miscellaneous USB options
#
CONFIG_USB_DEFAULT_PERSIST=y
# CONFIG_USB_FEW_INIT_RETRIES is not set
# CONFIG_USB_DYNAMIC_MINORS is not set
CONFIG_USB_OTG=y
# CONFIG_USB_OTG_PRODUCTLIST is not set
# CONFIG_USB_OTG_DISABLE_EXTERNAL_HUB is not set
# CONFIG_USB_OTG_FSM is not set
# CONFIG_USB_LEDS_TRIGGER_USBPORT is not set
CONFIG_USB_AUTOSUSPEND_DELAY=2
# CONFIG_USB_MON is not set

#
# USB Host Controller Drivers
#
# CONFIG_USB_C67X00_HCD is not set
CONFIG_USB_XHCI_HCD=y
# CONFIG_USB_XHCI_DBGCAP is not set
CONFIG_USB_XHCI_PCI=y
# CONFIG_USB_XHCI_PCI_RENESAS is not set
CONFIG_USB_XHCI_PLATFORM=y
# CONFIG_USB_XHCI_HISTB is not set
# CONFIG_USB_XHCI_MTK is not set
# CONFIG_USB_XHCI_MVEBU is not set
CONFIG_USB_XHCI_RCAR=y
CONFIG_USB_XHCI_TEGRA=y
# CONFIG_USB_BRCMSTB is not set
CONFIG_USB_EHCI_HCD=y
CONFIG_USB_EHCI_ROOT_HUB_TT=y
CONFIG_USB_EHCI_TT_NEWSCHED=y
CONFIG_USB_EHCI_PCI=y
# CONFIG_USB_EHCI_FSL is not set
# CONFIG_USB_EHCI_MXC is not set
CONFIG_USB_EHCI_HCD_ORION=y
# CONFIG_USB_EHCI_TEGRA is not set
CONFIG_USB_EHCI_EXYNOS=y
CONFIG_USB_EHCI_HCD_PLATFORM=y
# CONFIG_USB_OXU210HP_HCD is not set
# CONFIG_USB_ISP116X_HCD is not set
# CONFIG_USB_FOTG210_HCD is not set
# CONFIG_USB_MAX3421_HCD is not set
CONFIG_USB_OHCI_HCD=y
CONFIG_USB_OHCI_HCD_PCI=y
CONFIG_USB_OHCI_EXYNOS=y
CONFIG_USB_OHCI_HCD_PLATFORM=y
# CONFIG_USB_UHCI_HCD is not set
# CONFIG_USB_SL811_HCD is not set
# CONFIG_USB_R8A66597_HCD is not set
CONFIG_USB_RENESAS_USBHS_HCD=m
# CONFIG_USB_HCD_TEST_MODE is not set
CONFIG_USB_RENESAS_USBHS=m

#
# USB Device Class drivers
#
# CONFIG_USB_ACM is not set
# CONFIG_USB_PRINTER is not set
# CONFIG_USB_WDM is not set
# CONFIG_USB_TMC is not set

#
# NOTE: USB_STORAGE depends on SCSI but BLK_DEV_SD may #

# also be needed; see USB_STORAGE Help for more info
#
CONFIG_USB_STORAGE=y
# CONFIG_USB_STORAGE_DEBUG is not set
# CONFIG_USB_STORAGE_REALTEK is not set
# CONFIG_USB_STORAGE_DATAFAB is not set
# CONFIG_USB_STORAGE_FREECOM is not set
# CONFIG_USB_STORAGE_ISD200 is not set
# CONFIG_USB_STORAGE_USBAT is not set
# CONFIG_USB_STORAGE_SDDR09 is not set
# CONFIG_USB_STORAGE_SDDR55 is not set
# CONFIG_USB_STORAGE_JUMPSHOT is not set
# CONFIG_USB_STORAGE_ALAUDA is not set
# CONFIG_USB_STORAGE_ONETOUCH is not set
# CONFIG_USB_STORAGE_KARMA is not set
# CONFIG_USB_STORAGE_CYPRESS_ATACB is not set
# CONFIG_USB_STORAGE_ENE_UB6250 is not set
# CONFIG_USB_UAS is not set

#
# USB Imaging devices
#
# CONFIG_USB_MDC800 is not set
# CONFIG_USB_MICROTEK is not set
# CONFIG_USBIP_CORE is not set
# CONFIG_USB_CDNS3 is not set
# CONFIG_USB_MTU3 is not set
CONFIG_USB_MUSB_HDRC=y
# CONFIG_USB_MUSB_HOST is not set
# CONFIG_USB_MUSB_GADGET is not set
CONFIG_USB_MUSB_DUAL_ROLE=y

#
# Platform Glue Layer
#
CONFIG_USB_MUSB_SUNXI=y
# CONFIG_USB_MUSB_MEDIATEK is not set

#
# MUSB DMA mode
#
# CONFIG_MUSB_PIO_ONLY is not set
CONFIG_USB_DWC3=y
# CONFIG_USB_DWC3_ULPI is not set
# CONFIG_USB_DWC3_HOST is not set
# CONFIG_USB_DWC3_GADGET is not set
CONFIG_USB_DWC3_DUAL_ROLE=y

#
# Platform Glue Driver Support
#
CONFIG_USB_DWC3_EXYNOS=y
CONFIG_USB_DWC3_PCI=y
CONFIG_USB_DWC3_HAPS=y
CONFIG_USB_DWC3_KEYSTONE=y
CONFIG_USB_DWC3_MESON_G12A=y
CONFIG_USB_DWC3_OF_SIMPLE=y
CONFIG_USB_DWC3_QCOM=y
CONFIG_USB_DWC2=y
# CONFIG_USB_DWC2_HOST is not set

#
# Gadget/Dual-role mode requires USB Gadget support to be enabled #
# CONFIG_USB_DWC2_PERIPHERAL is not set CONFIG_USB_DWC2_DUAL_ROLE=y
# CONFIG_USB_DWC2_PCI is not set
# CONFIG_USB_DWC2_DEBUG is not set
# CONFIG_USB_DWC2_TRACK_MISSED_SOFS is not set CONFIG_USB_CHIPIDEA=y
CONFIG_USB_CHIPIDEA_UDC=y
CONFIG_USB_CHIPIDEA_HOST=y
CONFIG_USB_CHIPIDEA_PCI=y
CONFIG_USB_CHIPIDEA_MSM=y
CONFIG_USB_CHIPIDEA_IMX=y
CONFIG_USB_CHIPIDEA_GENERIC=y CONFIG_USB_CHIPIDEA_TEGRA=y
CONFIG_USB_ISP1760=y
CONFIG_USB_ISP1760_HCD=y
CONFIG_USB_ISP1761_UDC=y
# CONFIG_USB_ISP1760_HOST_ROLE is not set
# CONFIG_USB_ISP1760_GADGET_ROLE is not set CONFIG_USB_ISP1760_DUAL_ROLE=y

#
# USB port drivers
#
# CONFIG_USB_SERIAL is not set

2,800 lines not shown · raw message

Part of this message is not shown here. View the raw message.

Steven Rostedt

maintainer

2020-11-11 18:05 UTC #6 lore raw

Quoted 19 lines · On Wed, 11 Nov 2020 14:38:13 +0100 Marco Elver <[email protected]> wrote:

[+Cc folks who can maybe help figure out what's going on, since I get
warnings even without KFENCE on next-20201110.]
Quoted 15 lines · Marco Elver
On Wed, 11 Nov 2020 at 00:23, Anders Roxell <[email protected]> wrote:
[...]
Quoted 13 lines
I gave them a spin on next-20201105 [1] and on next-20201110 [2].
I eventually got to a prompt on next-20201105. However, I got to this kernel panic on the next-20201110:
[...]
[ 1514.089966][    T1] Testing event system initcall: OK
[ 1514.806232][    T1] Running tests on all trace events:
[ 1514.857835][    T1] Testing all events:
[ 1525.503262][    C0] hrtimer: interrupt took 10902600 ns
[ 1623.861452][    C0] BUG: workqueue lockup - pool cpus=0 node=0
flags=0x0 nice=0 stuck for 65s!
[...]

OK, so this blows up when you enable all events?

Note, it could just be adding overhead (which is exasperated with other debug options enabled), which could open up a race window.

Quoted 35 lines

Quoted 34 lines

[ 7823.104349][   T28]       Tainted: G        W
5.10.0-rc3-next-20201110-00008-g8dc06700529d #3
[ 7833.206491][   T28] "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 7840.750700][   T28] task:kworker/0:1     state:D stack:26640 pid:
1872 ppid:     2 flags:0x00000428
[ 7875.642531][   T28] Workqueue: events toggle_allocation_gate
[ 7889.178334][   T28] Call trace:
[ 7897.066649][   T28]  __switch_to+0x1cc/0x1e0
[ 7905.326856][   T28]  0xffff00000f7077b0
[ 7928.354644][   T28] INFO: lockdep is turned off.
[ 7934.022572][   T28] Kernel panic - not syncing: hung_task: blocked tasks
[ 7934.032039][   T28] CPU: 0 PID: 28 Comm: khungtaskd Tainted: G
  W         5.10.0-rc3-next-20201110-00008-g8dc06700529d #3
[ 7934.045586][   T28] Hardware name: linux,dummy-virt (DT)
[ 7934.053677][   T28] Call trace:
[ 7934.060276][   T28]  dump_backtrace+0x0/0x420
[ 7934.067635][   T28]  show_stack+0x38/0xa0
[ 7934.091277][   T28]  dump_stack+0x1d4/0x278
[ 7934.098878][   T28]  panic+0x304/0x5d8
[ 7934.114923][   T28]  check_hung_uninterruptible_tasks+0x5e4/0x640
[ 7934.123823][   T28]  watchdog+0x138/0x160
[ 7934.131561][   T28]  kthread+0x23c/0x260
[ 7934.138590][   T28]  ret_from_fork+0x10/0x18
[ 7934.146631][   T28] Kernel Offset: disabled
[ 7934.153749][   T28] CPU features: 0x0240002,20002004
[ 7934.161476][   T28] Memory Limit: none
[ 7934.171272][   T28] ---[ end Kernel panic - not syncing: hung_task:

blocked tasks ]---

Cheers,
Anders
[1] https://people.linaro.org/~anders.roxell/output-next-20201105-test.log
[2] https://people.linaro.org/~anders.roxell/output-next-20201110-test.log

Quoted 8 lines

Quoted 3 lines
Thanks for testing. The fact that it passes on next-20201105 but not on 20201110 is strange. If you boot with KFENCE disabled (boot param kfence.sample_interval=0), does it boot?
[...]
Right, so I think this is no longer KFENCE's fault. This looks like something scheduler/RCU/ftrace related?! I notice that there have been scheduler changes between next-20201105 and next-20201110.

I'm not sure any of that would cause this.

Quoted 20 lines

I get this with KFENCE disabled:

| Running tests on all trace events:
| Testing all events: 
| BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 32s!
| Showing busy workqueues and worker pools:
| workqueue events: flags=0x0
|   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
|     pending: vmstat_shepherd
| workqueue events_power_efficient: flags=0x82
|   pwq 2: cpus=0 flags=0x5 nice=0 active=2/256 refcnt=4
|     in-flight: 107:neigh_periodic_work
|     pending: do_cache_clean
| pool 2: cpus=0 flags=0x5 nice=0 hung=3s workers=2 manager: 7
| rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
| 	(detected by 0, t=6502 jiffies, g=2885, q=4)
| rcu: All QSes seen, last rcu_preempt kthread activity 5174 (4295523265-4295518091), jiffies_till_next_fqs=1, root ->qsmask 0x0
| rcu: rcu_preempt kthread starved for 5174 jiffies! g2885 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
| rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.

Quoted 8 lines

| rcu: RCU grace-period kthread stack dump:
| task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
| Call trace:
|  __switch_to+0x100/0x1e0
|  __schedule+0x2d0/0x890
|  preempt_schedule_notrace+0x70/0x1c0
|  ftrace_ops_no_ops+0x174/0x250
|  ftrace_graph_call+0x0/0xc

Note, just because ftrace is called here, the blocked task was preempted when the ftrace code called preempt_enable_notrace().

Quoted 7 lines

|  preempt_count_add+0x1c/0x180
|  schedule+0x44/0x108
|  schedule_timeout+0x394/0x530
|  rcu_gp_kthread+0x76c/0x19a8
|  kthread+0x174/0x188
|  ret_from_fork+0x10/0x18
|

Quoted 8 lines

| ================================
| WARNING: inconsistent lock state
| 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #18 Not tainted
| --------------------------------
| inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
| kcompactd0/26 [HC0[0]:SC0[0]:HE0:SE1] takes:
| ffffae32e6bd4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| {IN-HARDIRQ-W} state was registered at:

I did some digging here and it looks like the rcu_node lock could be taken without interrupts enabled when it does a stall print. That probably should be fixed, but it's a symptom of the underlining bug and not the cause.

-- Steve

Quoted 35 lines

|   __lock_acquire+0x7bc/0x15b8
|   lock_acquire+0x244/0x498
|   _raw_spin_lock_irqsave+0x78/0x144
|   rcu_sched_clock_irq+0x4a0/0xd18
|   update_process_times+0x68/0x98
|   tick_sched_handle.isra.16+0x54/0x80
|   tick_sched_timer+0x64/0xd8
|   __hrtimer_run_queues+0x2a4/0x750
| [...]
| irq event stamp: 270278
| hardirqs last  enabled at (270277): [<ffffae32e5a0bff8>] _raw_spin_unlock_irq+0x48/0x90
| hardirqs last disabled at (270278): [<ffffae32e46122bc>] el1_irq+0x7c/0x180
| softirqs last  enabled at (268786): [<ffffae32e4610b58>] __do_softirq+0x650/0x6a4
| softirqs last disabled at (268783): [<ffffae32e46c0b80>] irq_exit+0x1a8/0x1b0
| 
| other info that might help us debug this:
|  Possible unsafe locking scenario:
| 
|        CPU0
|        ----
|   lock(rcu_node_0);
|   <Interrupt>
|     lock(rcu_node_0);
| 
|  *** DEADLOCK ***
| 
| 1 lock held by kcompactd0/26:
|  #0: ffffae32e6bd4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| [...]

Full log and config attached. Also, I can provoke this quicker with the attached diff.

Thanks,
-- Marco

Paul E. McKenney

maintainer Tested-by Sebastian Andrzej Siewior

2020-11-11 18:23 UTC #7 lore raw

Quoted 124 lines · Steven Rostedt

Quoted 19 lines · On Wed, 11 Nov 2020 14:38:13 +0100 Marco Elver <[email protected]> wrote:
[+Cc folks who can maybe help figure out what's going on, since I get
warnings even without KFENCE on next-20201110.]
Quoted 15 lines · Marco Elver
On Wed, 11 Nov 2020 at 00:23, Anders Roxell <[email protected]> wrote:
[...]
Quoted 13 lines
I gave them a spin on next-20201105 [1] and on next-20201110 [2].
I eventually got to a prompt on next-20201105. However, I got to this kernel panic on the next-20201110:
[...]
[ 1514.089966][    T1] Testing event system initcall: OK
[ 1514.806232][    T1] Running tests on all trace events:
[ 1514.857835][    T1] Testing all events:
[ 1525.503262][    C0] hrtimer: interrupt took 10902600 ns
[ 1623.861452][    C0] BUG: workqueue lockup - pool cpus=0 node=0
flags=0x0 nice=0 stuck for 65s!
[...]
OK, so this blows up when you enable all events?
Note, it could just be adding overhead (which is exasperated with other debug options enabled), which could open up a race window.
Quoted 35 lines
Quoted 35 lines
Quoted 34 lines
[ 7823.104349][   T28]       Tainted: G        W
5.10.0-rc3-next-20201110-00008-g8dc06700529d #3
[ 7833.206491][   T28] "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 7840.750700][   T28] task:kworker/0:1     state:D stack:26640 pid:
1872 ppid:     2 flags:0x00000428
[ 7875.642531][   T28] Workqueue: events toggle_allocation_gate
[ 7889.178334][   T28] Call trace:
[ 7897.066649][   T28]  __switch_to+0x1cc/0x1e0
[ 7905.326856][   T28]  0xffff00000f7077b0
[ 7928.354644][   T28] INFO: lockdep is turned off.
[ 7934.022572][   T28] Kernel panic - not syncing: hung_task: blocked tasks
[ 7934.032039][   T28] CPU: 0 PID: 28 Comm: khungtaskd Tainted: G
  W         5.10.0-rc3-next-20201110-00008-g8dc06700529d #3
[ 7934.045586][   T28] Hardware name: linux,dummy-virt (DT)
[ 7934.053677][   T28] Call trace:
[ 7934.060276][   T28]  dump_backtrace+0x0/0x420
[ 7934.067635][   T28]  show_stack+0x38/0xa0
[ 7934.091277][   T28]  dump_stack+0x1d4/0x278
[ 7934.098878][   T28]  panic+0x304/0x5d8
[ 7934.114923][   T28]  check_hung_uninterruptible_tasks+0x5e4/0x640
[ 7934.123823][   T28]  watchdog+0x138/0x160
[ 7934.131561][   T28]  kthread+0x23c/0x260
[ 7934.138590][   T28]  ret_from_fork+0x10/0x18
[ 7934.146631][   T28] Kernel Offset: disabled
[ 7934.153749][   T28] CPU features: 0x0240002,20002004
[ 7934.161476][   T28] Memory Limit: none
[ 7934.171272][   T28] ---[ end Kernel panic - not syncing: hung_task:
blocked tasks ]---
Cheers,
Anders
[1] https://people.linaro.org/~anders.roxell/output-next-20201105-test.log
[2] https://people.linaro.org/~anders.roxell/output-next-20201110-test.log
Quoted 8 lines
Quoted 3 lines
Thanks for testing. The fact that it passes on next-20201105 but not on 20201110 is strange. If you boot with KFENCE disabled (boot param kfence.sample_interval=0), does it boot?
[...]
Right, so I think this is no longer KFENCE's fault. This looks like something scheduler/RCU/ftrace related?! I notice that there have been scheduler changes between next-20201105 and next-20201110.
I'm not sure any of that would cause this.
Quoted 20 lines
I get this with KFENCE disabled:
| Running tests on all trace events:
| Testing all events: 
| BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 32s!
| Showing busy workqueues and worker pools:
| workqueue events: flags=0x0
|   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
|     pending: vmstat_shepherd
| workqueue events_power_efficient: flags=0x82
|   pwq 2: cpus=0 flags=0x5 nice=0 active=2/256 refcnt=4
|     in-flight: 107:neigh_periodic_work
|     pending: do_cache_clean
| pool 2: cpus=0 flags=0x5 nice=0 hung=3s workers=2 manager: 7
| rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
| 	(detected by 0, t=6502 jiffies, g=2885, q=4)
| rcu: All QSes seen, last rcu_preempt kthread activity 5174 (4295523265-4295518091), jiffies_till_next_fqs=1, root ->qsmask 0x0
| rcu: rcu_preempt kthread starved for 5174 jiffies! g2885 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
| rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
Quoted 8 lines
| rcu: RCU grace-period kthread stack dump:
| task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
| Call trace:
|  __switch_to+0x100/0x1e0
|  __schedule+0x2d0/0x890
|  preempt_schedule_notrace+0x70/0x1c0
|  ftrace_ops_no_ops+0x174/0x250
|  ftrace_graph_call+0x0/0xc
Note, just because ftrace is called here, the blocked task was preempted when the ftrace code called preempt_enable_notrace().
Quoted 7 lines
|  preempt_count_add+0x1c/0x180
|  schedule+0x44/0x108
|  schedule_timeout+0x394/0x530
|  rcu_gp_kthread+0x76c/0x19a8
|  kthread+0x174/0x188
|  ret_from_fork+0x10/0x18
| 
Quoted 8 lines
| ================================
| WARNING: inconsistent lock state
| 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #18 Not tainted
| --------------------------------
| inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
| kcompactd0/26 [HC0[0]:SC0[0]:HE0:SE1] takes:
| ffffae32e6bd4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| {IN-HARDIRQ-W} state was registered at:

Quoted 3 lines

I did some digging here and it looks like the rcu_node lock could be taken without interrupts enabled when it does a stall print. That probably should be fixed, but it's a symptom of the underlining bug and not the cause.

Does this patch (in -next) help?

Thanx, Paul

------------------------------------------------------------------------

commit c583bcb8f5edd48c1798798e341f78afb9bf4f6f

Author: Paul E. McKenney <[email protected]>
Date:   Thu Sep 24 15:11:55 2020 -0700

rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled

The try_invoke_on_locked_down_task() function requires that interrupts be enabled, but it is called with interrupts disabled from rcu_print_task_stall(), resulting in an "IRQs not enabled as expected" diagnostic. This commit therefore updates rcu_print_task_stall() to accumulate a list of the first few tasks while holding the current leaf rcu_node structure's ->lock, then releases that lock and only then uses try_invoke_on_locked_down_task() to attempt to obtain per-task detailed information. Of course, as soon as ->lock is released, the task might exit, so the get_task_struct() function is used to prevent the task structure from going away in the meantime.

Link https://lore.kernel.org/lkml/[email protected]/ open here

Fixes 5bef8da66a9c ("rcu: Add per-task state to RCU CPU stall warnings")

Reported-by [email protected]

Tested-by Sebastian Andrzej Siewior <[email protected]>

Signed-off-by Paul E. McKenney <[email protected]>

kernel/rcu/tree_stall.h +17 -5

index 0fde39b..ca21d28 100644
@@ -249,13 +249,16 @@ static bool check_slow_task(struct task_struct *t, void *arg)
 
 /*
  * Scan the current list of tasks blocked within RCU read-side critical
- * sections, printing out the tid of each.
+ * sections, printing out the tid of each of the first few of them.
  */
-static int rcu_print_task_stall(struct rcu_node *rnp)
+static int rcu_print_task_stall(struct rcu_node *rnp, unsigned long flags)
+	__releases(rnp->lock)
 {
+	int i = 0;
 	int ndetected = 0;
 	struct rcu_stall_chk_rdr rscr;
 	struct task_struct *t;
+	struct task_struct *ts[8];
 
 	if (!rcu_preempt_blocked_readers_cgp(rnp))
 		return 0;

@@ -264,6 +267,14 @@ static int rcu_print_task_stall(struct rcu_node *rnp)
 	t = list_entry(rnp->gp_tasks->prev,
 		       struct task_struct, rcu_node_entry);
 	list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) {
+		get_task_struct(t);
+		ts[i++] = t;
+		if (i >= ARRAY_SIZE(ts))
+			break;
+	}
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	for (i--; i; i--) {
+		t = ts[i];
 		if (!try_invoke_on_locked_down_task(t, check_slow_task, &rscr))
 			pr_cont(" P%d", t->pid);
 		else

@@ -273,6 +284,7 @@ static int rcu_print_task_stall(struct rcu_node *rnp)
 				".q"[rscr.rs.b.need_qs],
 				".e"[rscr.rs.b.exp_hint],
 				".l"[rscr.on_blkd_list]);
+		put_task_struct(t);
 		ndetected++;
 	}
 	pr_cont("\n");

@@ -293,8 +305,9 @@ static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp)
  * Because preemptible RCU does not exist, we never have to check for
  * tasks blocked within RCU read-side critical sections.
  */
-static int rcu_print_task_stall(struct rcu_node *rnp)
+static int rcu_print_task_stall(struct rcu_node *rnp, unsigned long flags)
 {
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
 	return 0;
 }
 #endif /* #else #ifdef CONFIG_PREEMPT_RCU */

@@ -472,7 +485,6 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps)
 	pr_err("INFO: %s detected stalls on CPUs/tasks:\n", rcu_state.name);
 	rcu_for_each_leaf_node(rnp) {
 		raw_spin_lock_irqsave_rcu_node(rnp, flags);
-		ndetected += rcu_print_task_stall(rnp);
 		if (rnp->qsmask != 0) {
 			for_each_leaf_node_possible_cpu(rnp, cpu)
 				if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) {

@@ -480,7 +492,7 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps)
 					ndetected++;
 				}
 		}
-		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		ndetected += rcu_print_task_stall(rnp, flags); // Releases rnp->lock.
 	}
 
 	for_each_possible_cpu(cpu)

Marco Elver

author maintainer

2020-11-11 18:34 UTC #8 lore raw

Quoted 129 lines · Paul E. McKenney

Quoted 124 lines · Steven Rostedt
Quoted 19 lines · On Wed, 11 Nov 2020 14:38:13 +0100 Marco Elver <[email protected]> wrote:
[+Cc folks who can maybe help figure out what's going on, since I get
warnings even without KFENCE on next-20201110.]
Quoted 15 lines · Marco Elver
On Wed, 11 Nov 2020 at 00:23, Anders Roxell <[email protected]> wrote:
[...]
Quoted 13 lines
I gave them a spin on next-20201105 [1] and on next-20201110 [2].
I eventually got to a prompt on next-20201105. However, I got to this kernel panic on the next-20201110:
[...]
[ 1514.089966][    T1] Testing event system initcall: OK
[ 1514.806232][    T1] Running tests on all trace events:
[ 1514.857835][    T1] Testing all events:
[ 1525.503262][    C0] hrtimer: interrupt took 10902600 ns
[ 1623.861452][    C0] BUG: workqueue lockup - pool cpus=0 node=0
flags=0x0 nice=0 stuck for 65s!
[...]
OK, so this blows up when you enable all events?
Note, it could just be adding overhead (which is exasperated with other debug options enabled), which could open up a race window.
Quoted 35 lines
Quoted 35 lines
Quoted 34 lines
[ 7823.104349][   T28]       Tainted: G        W
5.10.0-rc3-next-20201110-00008-g8dc06700529d #3
[ 7833.206491][   T28] "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 7840.750700][   T28] task:kworker/0:1     state:D stack:26640 pid:
1872 ppid:     2 flags:0x00000428
[ 7875.642531][   T28] Workqueue: events toggle_allocation_gate
[ 7889.178334][   T28] Call trace:
[ 7897.066649][   T28]  __switch_to+0x1cc/0x1e0
[ 7905.326856][   T28]  0xffff00000f7077b0
[ 7928.354644][   T28] INFO: lockdep is turned off.
[ 7934.022572][   T28] Kernel panic - not syncing: hung_task: blocked tasks
[ 7934.032039][   T28] CPU: 0 PID: 28 Comm: khungtaskd Tainted: G
  W         5.10.0-rc3-next-20201110-00008-g8dc06700529d #3
[ 7934.045586][   T28] Hardware name: linux,dummy-virt (DT)
[ 7934.053677][   T28] Call trace:
[ 7934.060276][   T28]  dump_backtrace+0x0/0x420
[ 7934.067635][   T28]  show_stack+0x38/0xa0
[ 7934.091277][   T28]  dump_stack+0x1d4/0x278
[ 7934.098878][   T28]  panic+0x304/0x5d8
[ 7934.114923][   T28]  check_hung_uninterruptible_tasks+0x5e4/0x640
[ 7934.123823][   T28]  watchdog+0x138/0x160
[ 7934.131561][   T28]  kthread+0x23c/0x260
[ 7934.138590][   T28]  ret_from_fork+0x10/0x18
[ 7934.146631][   T28] Kernel Offset: disabled
[ 7934.153749][   T28] CPU features: 0x0240002,20002004
[ 7934.161476][   T28] Memory Limit: none
[ 7934.171272][   T28] ---[ end Kernel panic - not syncing: hung_task:
blocked tasks ]---
Cheers,
Anders
[1] https://people.linaro.org/~anders.roxell/output-next-20201105-test.log
[2] https://people.linaro.org/~anders.roxell/output-next-20201110-test.log
Quoted 8 lines
Quoted 3 lines
Thanks for testing. The fact that it passes on next-20201105 but not on 20201110 is strange. If you boot with KFENCE disabled (boot param kfence.sample_interval=0), does it boot?
[...]
Right, so I think this is no longer KFENCE's fault. This looks like something scheduler/RCU/ftrace related?! I notice that there have been scheduler changes between next-20201105 and next-20201110.
I'm not sure any of that would cause this.
Quoted 20 lines
I get this with KFENCE disabled:
| Running tests on all trace events:
| Testing all events: 
| BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 32s!
| Showing busy workqueues and worker pools:
| workqueue events: flags=0x0
|   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
|     pending: vmstat_shepherd
| workqueue events_power_efficient: flags=0x82
|   pwq 2: cpus=0 flags=0x5 nice=0 active=2/256 refcnt=4
|     in-flight: 107:neigh_periodic_work
|     pending: do_cache_clean
| pool 2: cpus=0 flags=0x5 nice=0 hung=3s workers=2 manager: 7
| rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
| 	(detected by 0, t=6502 jiffies, g=2885, q=4)
| rcu: All QSes seen, last rcu_preempt kthread activity 5174 (4295523265-4295518091), jiffies_till_next_fqs=1, root ->qsmask 0x0
| rcu: rcu_preempt kthread starved for 5174 jiffies! g2885 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
| rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
Quoted 8 lines
| rcu: RCU grace-period kthread stack dump:
| task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
| Call trace:
|  __switch_to+0x100/0x1e0
|  __schedule+0x2d0/0x890
|  preempt_schedule_notrace+0x70/0x1c0
|  ftrace_ops_no_ops+0x174/0x250
|  ftrace_graph_call+0x0/0xc
Note, just because ftrace is called here, the blocked task was preempted when the ftrace code called preempt_enable_notrace().
Quoted 7 lines
|  preempt_count_add+0x1c/0x180
|  schedule+0x44/0x108
|  schedule_timeout+0x394/0x530
|  rcu_gp_kthread+0x76c/0x19a8
|  kthread+0x174/0x188
|  ret_from_fork+0x10/0x18
| 
Quoted 8 lines
| ================================
| WARNING: inconsistent lock state
| 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #18 Not tainted
| --------------------------------
| inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
| kcompactd0/26 [HC0[0]:SC0[0]:HE0:SE1] takes:
| ffffae32e6bd4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| {IN-HARDIRQ-W} state was registered at:
Quoted 3 lines
I did some digging here and it looks like the rcu_node lock could be taken without interrupts enabled when it does a stall print. That probably should be fixed, but it's a symptom of the underlining bug and not the cause.

Quoted 5 lines

Does this patch (in -next) help?
Thanx, Paul
rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled

Sadly, no, next-20201110 already included that one, and that's what I tested and got me all those warnings above.

Thanks,
-- Marco

Paul E. McKenney

maintainer

2020-11-11 19:21 UTC #9 lore raw

Quoted 130 lines · Marco Elver

Quoted 129 lines · Paul E. McKenney
Quoted 127 lines · Steven Rostedt
Quoted 19 lines · On Wed, 11 Nov 2020 14:38:13 +0100 Marco Elver <[email protected]> wrote:
[+Cc folks who can maybe help figure out what's going on, since I get
warnings even without KFENCE on next-20201110.]
Quoted 15 lines · Marco Elver
On Wed, 11 Nov 2020 at 00:23, Anders Roxell <[email protected]> wrote:
[...]
Quoted 13 lines
I gave them a spin on next-20201105 [1] and on next-20201110 [2].
I eventually got to a prompt on next-20201105. However, I got to this kernel panic on the next-20201110:
[...]
[ 1514.089966][    T1] Testing event system initcall: OK
[ 1514.806232][    T1] Running tests on all trace events:
[ 1514.857835][    T1] Testing all events:
[ 1525.503262][    C0] hrtimer: interrupt took 10902600 ns
[ 1623.861452][    C0] BUG: workqueue lockup - pool cpus=0 node=0
flags=0x0 nice=0 stuck for 65s!
[...]
OK, so this blows up when you enable all events?
Note, it could just be adding overhead (which is exasperated with other debug options enabled), which could open up a race window.
Quoted 35 lines
Quoted 35 lines
Quoted 34 lines
[ 7823.104349][   T28]       Tainted: G        W
5.10.0-rc3-next-20201110-00008-g8dc06700529d #3
[ 7833.206491][   T28] "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 7840.750700][   T28] task:kworker/0:1     state:D stack:26640 pid:
1872 ppid:     2 flags:0x00000428
[ 7875.642531][   T28] Workqueue: events toggle_allocation_gate
[ 7889.178334][   T28] Call trace:
[ 7897.066649][   T28]  __switch_to+0x1cc/0x1e0
[ 7905.326856][   T28]  0xffff00000f7077b0
[ 7928.354644][   T28] INFO: lockdep is turned off.
[ 7934.022572][   T28] Kernel panic - not syncing: hung_task: blocked tasks
[ 7934.032039][   T28] CPU: 0 PID: 28 Comm: khungtaskd Tainted: G
  W         5.10.0-rc3-next-20201110-00008-g8dc06700529d #3
[ 7934.045586][   T28] Hardware name: linux,dummy-virt (DT)
[ 7934.053677][   T28] Call trace:
[ 7934.060276][   T28]  dump_backtrace+0x0/0x420
[ 7934.067635][   T28]  show_stack+0x38/0xa0
[ 7934.091277][   T28]  dump_stack+0x1d4/0x278
[ 7934.098878][   T28]  panic+0x304/0x5d8
[ 7934.114923][   T28]  check_hung_uninterruptible_tasks+0x5e4/0x640
[ 7934.123823][   T28]  watchdog+0x138/0x160
[ 7934.131561][   T28]  kthread+0x23c/0x260
[ 7934.138590][   T28]  ret_from_fork+0x10/0x18
[ 7934.146631][   T28] Kernel Offset: disabled
[ 7934.153749][   T28] CPU features: 0x0240002,20002004
[ 7934.161476][   T28] Memory Limit: none
[ 7934.171272][   T28] ---[ end Kernel panic - not syncing: hung_task:
blocked tasks ]---
Cheers,
Anders
[1] https://people.linaro.org/~anders.roxell/output-next-20201105-test.log
[2] https://people.linaro.org/~anders.roxell/output-next-20201110-test.log
Quoted 8 lines
Quoted 3 lines
Thanks for testing. The fact that it passes on next-20201105 but not on 20201110 is strange. If you boot with KFENCE disabled (boot param kfence.sample_interval=0), does it boot?
[...]
Right, so I think this is no longer KFENCE's fault. This looks like something scheduler/RCU/ftrace related?! I notice that there have been scheduler changes between next-20201105 and next-20201110.
I'm not sure any of that would cause this.
Quoted 20 lines
I get this with KFENCE disabled:
| Running tests on all trace events:
| Testing all events: 
| BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 32s!
| Showing busy workqueues and worker pools:
| workqueue events: flags=0x0
|   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
|     pending: vmstat_shepherd
| workqueue events_power_efficient: flags=0x82
|   pwq 2: cpus=0 flags=0x5 nice=0 active=2/256 refcnt=4
|     in-flight: 107:neigh_periodic_work
|     pending: do_cache_clean
| pool 2: cpus=0 flags=0x5 nice=0 hung=3s workers=2 manager: 7
| rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
| 	(detected by 0, t=6502 jiffies, g=2885, q=4)
| rcu: All QSes seen, last rcu_preempt kthread activity 5174 (4295523265-4295518091), jiffies_till_next_fqs=1, root ->qsmask 0x0
| rcu: rcu_preempt kthread starved for 5174 jiffies! g2885 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
| rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
Quoted 8 lines
| rcu: RCU grace-period kthread stack dump:
| task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
| Call trace:
|  __switch_to+0x100/0x1e0
|  __schedule+0x2d0/0x890
|  preempt_schedule_notrace+0x70/0x1c0
|  ftrace_ops_no_ops+0x174/0x250
|  ftrace_graph_call+0x0/0xc
Note, just because ftrace is called here, the blocked task was preempted when the ftrace code called preempt_enable_notrace().
Quoted 7 lines
|  preempt_count_add+0x1c/0x180
|  schedule+0x44/0x108
|  schedule_timeout+0x394/0x530
|  rcu_gp_kthread+0x76c/0x19a8
|  kthread+0x174/0x188
|  ret_from_fork+0x10/0x18
| 
Quoted 8 lines
| ================================
| WARNING: inconsistent lock state
| 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #18 Not tainted
| --------------------------------
| inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
| kcompactd0/26 [HC0[0]:SC0[0]:HE0:SE1] takes:
| ffffae32e6bd4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| {IN-HARDIRQ-W} state was registered at:
I did some digging here and it looks like the rcu_node lock could be taken without interrupts enabled when it does a stall print. That probably should be fixed, but it's a symptom of the underlining bug and not the cause.

Quoted 8 lines

Quoted 5 lines
Does this patch (in -next) help?
Thanx, Paul
rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled
Sadly, no, next-20201110 already included that one, and that's what I tested and got me all those warnings above.

Hey, I had to ask! The only uncertainty I seee is the acquisition of the lock in rcu_iw_handler(), for which I add a lockdep check in the (untested) patch below. The other thing I could do is sprinkle such checks through the stall-warning code on the assumption that something RCU is calling is enabling interrupts.

Other thoughts?

Thanx, Paul

------------------------------------------------------------------------

kernel/rcu/tree_stall.h +1 -0

index 70d48c5..3d67650 100644
@@ -189,6 +189,7 @@ static void rcu_iw_handler(struct irq_work *iwp)
 
 	rdp = container_of(iwp, struct rcu_data, rcu_iw);
 	rnp = rdp->mynode;
+	lockdep_assert_irqs_disabled();
 	raw_spin_lock_rcu_node(rnp);
 	if (!WARN_ON_ONCE(!rdp->rcu_iw_pending)) {
 		rdp->rcu_iw_gp_seq = rnp->gp_seq;

Marco Elver

author maintainer

2020-11-11 20:22 UTC #10 lore raw

On Wed, Nov 11, 2020 at 11:21AM -0800, Paul E. McKenney wrote:
[...]

Quoted 22 lines

Quoted 4 lines
Quoted 1 line
rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled
Sadly, no, next-20201110 already included that one, and that's what I tested and got me all those warnings above.
Hey, I had to ask! The only uncertainty I seee is the acquisition of the lock in rcu_iw_handler(), for which I add a lockdep check in the (untested) patch below. The other thing I could do is sprinkle such checks through the stall-warning code on the assumption that something RCU is calling is enabling interrupts.
Other thoughts?
Thanx, Paul
------------------------------------------------------------------------
kernel/rcu/tree_stall.h +0 -0
index 70d48c5..3d67650 100644

kernel/rcu/tree_stall.h static void rcu_iw_handler(struct irq_work *iwp) · line 195

Quoted 7 lines

kernel/rcu/tree_stall.h +1 -0

@@ -189,6 +189,7 @@ static void rcu_iw_handler(struct irq_work *iwp)
 
 	rdp = container_of(iwp, struct rcu_data, rcu_iw);
 	rnp = rdp->mynode;
+	lockdep_assert_irqs_disabled();
 	raw_spin_lock_rcu_node(rnp);
 	if (!WARN_ON_ONCE(!rdp->rcu_iw_pending)) {
 		rdp->rcu_iw_gp_seq = rnp->gp_seq;

This assert didn't fire yet, I just get more of the below. I'll keep rerunning, but am not too hopeful...

Thanks,
-- Marco

| [...]
| [  125.854798] registered taskstats version 1
| [  125.857453] Running tests on all trace events:
| [  125.857830] Testing all events: OK
| [  166.950008] hrtimer: interrupt took 16803216 ns
| [  181.867305] Running tests again, along with the function tracer
| [  181.882932] Running tests on all trace events:
| [  181.894437] Testing all events: 
| [  415.596777] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 34s!
| [  415.656078] Showing busy workqueues and worker pools:
| [  415.683616] workqueue events: flags=0x0
| [  415.692860]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  415.710520]     pending: vmstat_shepherd
| [  415.735770] workqueue mm_percpu_wq: flags=0x8
| [  415.744135]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  415.759123]     in-flight: 15:vmstat_update
| [  415.784113] pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=34s workers=2 idle: 5
| [  510.976952] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 31s!
| [  511.054367] Showing busy workqueues and worker pools:
| [  511.060173] workqueue events: flags=0x0
| [  511.083325]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=2/256 refcnt=3
| [  511.093457]     in-flight: 15:vmstat_shepherd
| [  511.100300]     pending: free_work
| [  511.111488] workqueue events_power_efficient: flags=0x82
| [  511.141245]   pwq 2: cpus=0 flags=0x5 nice=0 active=3/256 refcnt=5
| [  511.151184]     in-flight: 7:check_lifetime
| [  511.157902]     pending: neigh_periodic_work, do_cache_clean
| [  511.171073] workqueue mm_percpu_wq: flags=0x8
| [  511.198620]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  511.208715]     pending: vmstat_update
| [  511.227644] pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=31s workers=2 idle: 5
| [  511.255656] pool 2: cpus=0 flags=0x5 nice=0 hung=19s workers=2 manager: 61
| [  544.063224] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 64s!
| [  544.174957] Showing busy workqueues and worker pools:
| [  544.223112] workqueue events: flags=0x0
| [  544.250341]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=2/256 refcnt=3
| [  544.260574]     in-flight: 15:vmstat_shepherd
| [  544.267433]     pending: free_work
| [  544.285271] workqueue mm_percpu_wq: flags=0x8
| [  544.290950]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  544.301150]     pending: vmstat_update
| [  544.315536] pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=64s workers=2 idle: 5
| [  544.339558] pool 2: cpus=0 flags=0x5 nice=0 hung=5s workers=2 manager: 61 idle: 7
| [  790.375433] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 32s!
| [  790.435529] Showing busy workqueues and worker pools:
| [  790.455374] workqueue events: flags=0x0
| [  790.471271]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  790.481737]     in-flight: 15:vmstat_shepherd
| [  790.495314] workqueue events_power_efficient: flags=0x82
| [  790.512837]   pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3
| [  790.521833]     in-flight: 107:neigh_periodic_work
| [  790.535532] workqueue mm_percpu_wq: flags=0x8
| [  790.555139]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  790.565610]     pending: vmstat_update
| [  790.579066] pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=32s workers=2 idle: 5
| [  790.603124] pool 2: cpus=0 flags=0x4 nice=0 hung=1s workers=3 idle: 7 61
| [  950.115427] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 40s!
| [  950.177846] Showing busy workqueues and worker pools:
| [  950.183602] workqueue events: flags=0x0
| [  950.207180]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  950.217258]     pending: vmstat_shepherd
| [  992.571446] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 82s!
| [  992.662876] Showing busy workqueues and worker pools:
| [  992.668626] workqueue events: flags=0x0
| [  992.691443]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  992.701473]     pending: vmstat_shepherd
| [ 1001.181519] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
| [ 1001.186952] 	(detected by 0, t=6502 jiffies, g=3441, q=1)
| [ 1001.188828] rcu: All QSes seen, last rcu_preempt kthread activity 528 (4295139809-4295139281), jiffies_till_next_fqs=1, root ->qsmask 0x0
| [ 1001.199298] rcu: rcu_preempt kthread starved for 528 jiffies! g3441 f0x2 RCU_GP_CLEANUP(7) ->state=0x0 ->cpu=0
| [ 1001.205008] rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
| [ 1001.210324] rcu: RCU grace-period kthread stack dump:
| [ 1001.214618] task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
| [ 1001.223303] Call trace:
| [ 1001.226919]  __switch_to+0x100/0x1e0
| [ 1001.230803]  __schedule+0x2d0/0x890
| [ 1001.234685]  preempt_schedule_common+0xd4/0x1b0
| [ 1001.238831]  preempt_schedule.part.88+0x20/0x28
| [ 1001.242963]  preempt_schedule+0x20/0x28
| [ 1001.246928]  _raw_spin_unlock_irq+0x80/0x90
| [ 1001.251011]  rcu_gp_kthread+0xe5c/0x19a8
| [ 1001.255024]  kthread+0x174/0x188
| [ 1001.258821]  ret_from_fork+0x10/0x18
| [ 1001.274658] 
| [ 1001.276945] ================================
| [ 1001.279954] WARNING: inconsistent lock state
| [ 1001.283169] 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #2 Not tainted
| [ 1001.287067] --------------------------------
| [ 1001.290073] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
| [ 1001.293767] ksoftirqd/0/9 [HC0[0]:SC0[0]:HE0:SE1] takes:
| [ 1001.297148] ffffd53efd5d4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| [ 1001.305027] {IN-HARDIRQ-W} state was registered at:
| [ 1001.308401]   __lock_acquire+0x7bc/0x15b8
| [ 1001.311430]   lock_acquire+0x244/0x498
| [ 1001.314341]   _raw_spin_lock+0x5c/0x78
| [ 1001.317252]   rcu_preempt_deferred_qs_irqrestore+0x84/0x540
| [ 1001.320666]   rcu_preempt_deferred_qs+0x64/0x80
| [ 1001.323789]   rcu_sched_clock_irq+0x4f4/0xd18
| [ 1001.326881]   update_process_times+0x68/0x98
| [ 1001.329932]   tick_sched_handle.isra.16+0x54/0x80
| [ 1001.333110]   tick_sched_timer+0x64/0xd8
| [ 1001.336085]   __hrtimer_run_queues+0x2a4/0x750
| [ 1001.339194]   hrtimer_interrupt+0xf4/0x2a0
| [ 1001.342244]   arch_timer_handler_virt+0x44/0x70
| [ 1001.345419]   handle_percpu_devid_irq+0xfc/0x4d0
| [ 1001.348579]   generic_handle_irq+0x50/0x70
| [ 1001.351596]   __handle_domain_irq+0x9c/0x120
| [ 1001.354677]   gic_handle_irq+0xcc/0x108
| [ 1001.357651]   el1_irq+0xbc/0x180
| [ 1001.360429]   arch_local_irq_save+0x18/0x30
| [ 1001.363460]   __rcu_read_unlock+0x84/0x1d8
| [ 1001.366461]   check_lifetime+0x158/0x4e0
| [ 1001.369460]   process_one_work+0x2c4/0x828
| [ 1001.372486]   worker_thread+0x5c/0x518
| [ 1001.375432]   kthread+0x174/0x188
| [ 1001.378232]   ret_from_fork+0x10/0x18
| [ 1001.381101] irq event stamp: 68414
| [ 1001.383978] hardirqs last  enabled at (68413): [<ffffd53efb1856d0>] rcu_irq_exit_irqson+0x48/0x68
| [ 1001.388412] hardirqs last disabled at (68414): [<ffffd53efb0122bc>] el1_irq+0x7c/0x180
| [ 1001.392557] softirqs last  enabled at (68214): [<ffffd53efb010b58>] __do_softirq+0x650/0x6a4
| [ 1001.396858] softirqs last disabled at (68211): [<ffffd53efb0c0b80>] irq_exit+0x1a8/0x1b0
| [ 1001.400907] 
| [ 1001.400907] other info that might help us debug this:
| [ 1001.404542]  Possible unsafe locking scenario:
| [ 1001.404542] 
| [ 1001.407936]        CPU0
| [ 1001.410369]        ----
| [ 1001.412815]   lock(rcu_node_0);
| [ 1001.417183]   <Interrupt>
| [ 1001.419715]     lock(rcu_node_0);
| [ 1001.424132] 
| [ 1001.424132]  *** DEADLOCK ***
| [ 1001.424132] 
| [ 1001.427638] 1 lock held by ksoftirqd/0/9:
| [ 1001.430588]  #0: ffffd53efd5d4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| [ 1001.439283] 
| [ 1001.439283] stack backtrace:
| [ 1001.442601] CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #2
| [ 1001.447258] Hardware name: linux,dummy-virt (DT)
| [ 1001.450435] Call trace:
| [ 1001.452985]  dump_backtrace+0x0/0x278
| [ 1001.455904]  show_stack+0x30/0x80
| [ 1001.458690]  dump_stack+0x138/0x1b0
| [ 1001.461525]  print_usage_bug+0x2d8/0x2f8
| [ 1001.464511]  mark_lock.part.46+0x370/0x480
| [ 1001.467538]  mark_held_locks+0x58/0x90
| [ 1001.470495]  lockdep_hardirqs_on_prepare+0xdc/0x298
| [ 1001.473751]  trace_hardirqs_on+0x90/0x388
| [ 1001.476744]  el1_irq+0xd8/0x180
| [ 1001.479486]  arch_local_irq_restore+0x4/0x8
| [ 1001.482521]  trace_preempt_off+0x138/0x1e8
| [ 1001.485531]  preempt_schedule_notrace+0xec/0x1c0
| [ 1001.488707]  ftrace_ops_no_ops+0x174/0x250
| [ 1001.491730]  ftrace_graph_call+0x0/0xc
| [ 1001.494647]  preempt_count_add+0x1c/0x180
| [ 1001.497642]  schedule+0x44/0x108
| [ 1001.500440]  smpboot_thread_fn+0x160/0x298
| [ 1001.503470]  kthread+0x174/0x188
| [ 1001.506245]  ret_from_fork+0x10/0x18
| [ 1001.513585] BUG: scheduling while atomic: ksoftirqd/0/9/0x00000002
| [ 1001.522142] INFO: lockdep is turned off.
| [ 1001.530315] Modules linked in:
| [ 1001.542198] Preemption disabled at:
| [ 1001.546077] [<ffffd53efb219d74>] ftrace_ops_no_ops+0x174/0x250
| [ 1001.558740] CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #2
| [ 1001.563426] Hardware name: linux,dummy-virt (DT)
| [ 1001.566615] Call trace:
| [ 1001.569206]  dump_backtrace+0x0/0x278
| [ 1001.572108]  show_stack+0x30/0x80
| [ 1001.574947]  dump_stack+0x138/0x1b0
| [ 1001.577814]  __schedule_bug+0x8c/0xe8
| [ 1001.580769]  __schedule+0x7e8/0x890
| [ 1001.583679]  preempt_schedule_notrace+0x70/0x1c0
| [ 1001.586883]  ftrace_ops_no_ops+0x174/0x250
| [ 1001.589939]  ftrace_graph_call+0x0/0xc
| [ 1001.592891]  preempt_count_add+0x1c/0x180
| [ 1001.595925]  schedule+0x44/0x108
| [ 1001.598741]  smpboot_thread_fn+0x160/0x298
| [ 1001.601808]  kthread+0x174/0x188
| [ 1001.604629]  ret_from_fork+0x10/0x18

Paul E. McKenney

maintainer

2020-11-12 00:11 UTC #11 lore raw

Quoted 25 lines · Marco Elver

On Wed, Nov 11, 2020 at 11:21AM -0800, Paul E. McKenney wrote:
[...]
Quoted 23 lines
Quoted 4 lines
Quoted 1 line
rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled
Sadly, no, next-20201110 already included that one, and that's what I tested and got me all those warnings above.
Hey, I had to ask! The only uncertainty I seee is the acquisition of the lock in rcu_iw_handler(), for which I add a lockdep check in the (untested) patch below. The other thing I could do is sprinkle such checks through the stall-warning code on the assumption that something RCU is calling is enabling interrupts.
Other thoughts?
Thanx, Paul
------------------------------------------------------------------------
kernel/rcu/tree_stall.h +0 -0
index 70d48c5..3d67650 100644
@@ -189,6 +189,7 @@ static void rcu_iw_handler(struct irq_work *iwp)
 

Quoted 9 lines

kernel/rcu/tree_stall.h static void rcu_iw_handler(struct irq_work *iwp) · line 195
Quoted 6 lines
kernel/rcu/tree_stall.h +1 -0
 	rdp = container_of(iwp, struct rcu_data, rcu_iw);
 	rnp = rdp->mynode;
+	lockdep_assert_irqs_disabled();
 	raw_spin_lock_rcu_node(rnp);
 	if (!WARN_ON_ONCE(!rdp->rcu_iw_pending)) {
 		rdp->rcu_iw_gp_seq = rnp->gp_seq;
This assert didn't fire yet, I just get more of the below. I'll keep rerunning, but am not too hopeful...

Is bisection a possibility?

Failing that, please see the updated patch below. This adds a few more calls to lockdep_assert_irqs_disabled(), but perhaps more helpfully dumps the current stack of the CPU that the RCU grace-period kthread wants to run on in the case where this kthread has been starved of CPU.

Thanx, Paul

------------------------------------------------------------------------

kernel/rcu/tree_stall.h +13 -1

index 70d48c5..d203ea0 100644
@@ -189,6 +189,7 @@ static void rcu_iw_handler(struct irq_work *iwp)
 
 	rdp = container_of(iwp, struct rcu_data, rcu_iw);
 	rnp = rdp->mynode;
+	lockdep_assert_irqs_disabled();
 	raw_spin_lock_rcu_node(rnp);
 	if (!WARN_ON_ONCE(!rdp->rcu_iw_pending)) {
 		rdp->rcu_iw_gp_seq = rnp->gp_seq;

@@ -449,21 +450,32 @@ static void print_cpu_stall_info(int cpu)
 /* Complain about starvation of grace-period kthread.  */
 static void rcu_check_gp_kthread_starvation(void)
 {
+	int cpu;
 	struct task_struct *gpk = rcu_state.gp_kthread;
 	unsigned long j;
 
 	if (rcu_is_gp_kthread_starving(&j)) {
+		cpu = gpk ? task_cpu(gpk) : -1;
 		pr_err("%s kthread starved for %ld jiffies! g%ld f%#x %s(%d) ->state=%#lx ->cpu=%d\n",
 		       rcu_state.name, j,
 		       (long)rcu_seq_current(&rcu_state.gp_seq),
 		       data_race(rcu_state.gp_flags),
 		       gp_state_getname(rcu_state.gp_state), rcu_state.gp_state,
-		       gpk ? gpk->state : ~0, gpk ? task_cpu(gpk) : -1);
+		       gpk ? gpk->state : ~0, cpu);
 		if (gpk) {
 			pr_err("\tUnless %s kthread gets sufficient CPU time, OOM is now expected behavior.\n", rcu_state.name);
 			pr_err("RCU grace-period kthread stack dump:\n");
+			lockdep_assert_irqs_disabled();
 			sched_show_task(gpk);
+			lockdep_assert_irqs_disabled();
+			if (cpu >= 0) {
+				pr_err("Stack dump where RCU grace-period kthread last ran:\n");
+				if (!trigger_single_cpu_backtrace(cpu))
+					dump_cpu_task(cpu);
+			}
+			lockdep_assert_irqs_disabled();
 			wake_up_process(gpk);
+			lockdep_assert_irqs_disabled();
 		}
 	}
 }

Marco Elver

author maintainer

2020-11-12 12:49 UTC #12 lore raw

Quoted 37 lines · Paul E. McKenney

Quoted 25 lines · Marco Elver
On Wed, Nov 11, 2020 at 11:21AM -0800, Paul E. McKenney wrote:
[...]
Quoted 23 lines
Quoted 4 lines
Quoted 1 line
rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled
Sadly, no, next-20201110 already included that one, and that's what I tested and got me all those warnings above.
Hey, I had to ask! The only uncertainty I seee is the acquisition of the lock in rcu_iw_handler(), for which I add a lockdep check in the (untested) patch below. The other thing I could do is sprinkle such checks through the stall-warning code on the assumption that something RCU is calling is enabling interrupts.
Other thoughts?
Thanx, Paul
------------------------------------------------------------------------
kernel/rcu/tree_stall.h +0 -0
index 70d48c5..3d67650 100644
@@ -189,6 +189,7 @@ static void rcu_iw_handler(struct irq_work *iwp)
 
Quoted 9 lines
kernel/rcu/tree_stall.h static void rcu_iw_handler(struct irq_work *iwp) · line 195
Quoted 6 lines
kernel/rcu/tree_stall.h +1 -0
    rdp = container_of(iwp, struct rcu_data, rcu_iw);
    rnp = rdp->mynode;
+   lockdep_assert_irqs_disabled();
    raw_spin_lock_rcu_node(rnp);
    if (!WARN_ON_ONCE(!rdp->rcu_iw_pending)) {
            rdp->rcu_iw_gp_seq = rnp->gp_seq;
This assert didn't fire yet, I just get more of the below. I'll keep rerunning, but am not too hopeful...

Quoted 1 line

Is bisection a possibility?

I've been running a bisection for past ~12h, and am making slow progress. It might be another 12h, but I think it'll get there.

Quoted 4 lines

Failing that, please see the updated patch below. This adds a few more calls to lockdep_assert_irqs_disabled(), but perhaps more helpfully dumps the current stack of the CPU that the RCU grace-period kthread wants to run on in the case where this kthread has been starved of CPU.

Thanks, I will apply that after the bisection runs.

Quoted 50 lines

Thanx, Paul

------------------------------------------------------------------------

kernel/rcu/tree_stall.h +13 -1

index 70d48c5..d203ea0 100644
@@ -189,6 +189,7 @@ static void rcu_iw_handler(struct irq_work *iwp)
 
        rdp = container_of(iwp, struct rcu_data, rcu_iw);
        rnp = rdp->mynode;
+       lockdep_assert_irqs_disabled();
        raw_spin_lock_rcu_node(rnp);
        if (!WARN_ON_ONCE(!rdp->rcu_iw_pending)) {
                rdp->rcu_iw_gp_seq = rnp->gp_seq;

@@ -449,21 +450,32 @@ static void print_cpu_stall_info(int cpu)
 /* Complain about starvation of grace-period kthread.  */
 static void rcu_check_gp_kthread_starvation(void)
 {
+       int cpu;
        struct task_struct *gpk = rcu_state.gp_kthread;
        unsigned long j;
 
        if (rcu_is_gp_kthread_starving(&j)) {
+               cpu = gpk ? task_cpu(gpk) : -1;
                pr_err("%s kthread starved for %ld jiffies! g%ld f%#x %s(%d) ->state=%#lx ->cpu=%d\n",
                       rcu_state.name, j,
                       (long)rcu_seq_current(&rcu_state.gp_seq),
                       data_race(rcu_state.gp_flags),
                       gp_state_getname(rcu_state.gp_state), rcu_state.gp_state,
-                      gpk ? gpk->state : ~0, gpk ? task_cpu(gpk) : -1);
+                      gpk ? gpk->state : ~0, cpu);
                if (gpk) {
                        pr_err("\tUnless %s kthread gets sufficient CPU time, OOM is now expected behavior.\n", rcu_state.name);
                        pr_err("RCU grace-period kthread stack dump:\n");
+                       lockdep_assert_irqs_disabled();
                        sched_show_task(gpk);
+                       lockdep_assert_irqs_disabled();
+                       if (cpu >= 0) {
+                               pr_err("Stack dump where RCU grace-period kthread last ran:\n");
+                               if (!trigger_single_cpu_backtrace(cpu))
+                                       dump_cpu_task(cpu);
+                       }
+                       lockdep_assert_irqs_disabled();
                        wake_up_process(gpk);
+                       lockdep_assert_irqs_disabled();
                }
        }
 }

Marco Elver

author maintainer

2020-11-12 16:14 UTC #13 lore raw

Quoted 1 line · Marco Elver

On Thu, 12 Nov 2020 at 01:11, Paul E. McKenney <[email protected]> wrote:

[...]

Quoted 7 lines

Quoted 4 lines
Quoted 2 lines
This assert didn't fire yet, I just get more of the below. I'll keep rerunning, but am not too hopeful...
Is bisection a possibility?
I've been running a bisection for past ~12h, and am making slow progress. It might be another 12h, but I think it'll get there.

Bisection gave me this:

| git bisect start
| # bad: [c07b306d7fa5680777e2132662d2e6c19fb53579] kfence: Avoid stalling work queue task without allocations
| git bisect bad c07b306d7fa5680777e2132662d2e6c19fb53579
| # good: [3cea11cd5e3b00d91caf0b4730194039b45c5891] Linux 5.10-rc2
| git bisect good 27598e7e73260ed0b2917eb02d4a515ebb578313
| # good: [3e5acbea719e66ef3be64fe74c99cc905ca697dc] Merge remote-tracking branch 'wireless-drivers-next/master' into master
| git bisect good 3e5acbea719e66ef3be64fe74c99cc905ca697dc
| # good: [491a5a9a2fea28353d99621b8abb83b6928b4e36] Merge remote-tracking branch 'sound-asoc/for-next' into master
| git bisect good 491a5a9a2fea28353d99621b8abb83b6928b4e36
| # bad: [502f8643d6e21c7e370a0b75131130cc51609055] Merge remote-tracking branch 'phy-next/next' into master
| git bisect bad 502f8643d6e21c7e370a0b75131130cc51609055
| # good: [6693cb1fa5ea7b91ec00f9404776a095713face5] Merge remote-tracking branch 'tip/auto-latest' into master
| git bisect good 6693cb1fa5ea7b91ec00f9404776a095713face5
| # bad: [b790e3afead9357195b6d1e1b6cd9b3521503ad2] Merge branch 'tglx-pc.2020.10.30a' into HEAD
| git bisect bad b790e3afead9357195b6d1e1b6cd9b3521503ad2
| # bad: [765b512bb3d639bfad7dd43c288ee085236c7267] Merge branches 'cpuinfo.2020.11.06a', 'doc.2020.11.06a', 'fixes.2020.11.02a', 'lockdep.2020.11.02a', 'tasks.2020.11.06a' and 'torture.2020.11.06a' into HEAD
| git bisect bad 765b512bb3d639bfad7dd43c288ee085236c7267
| # good: [01f9e708d9eae6335ae9ff25ab09893c20727a55] tools/rcutorture: Fix BUG parsing of console.log
| git bisect good 01f9e708d9eae6335ae9ff25ab09893c20727a55
| # good: [1be6ab91e2db157faedb7f16ab0636a80745a073] srcu: Take early exit on memory-allocation failure
| git bisect good 1be6ab91e2db157faedb7f16ab0636a80745a073
| # good: [65e9eb1ccfe56b41a0d8bfec651ea014968413cb] rcu: Prevent RCU_LOCKDEP_WARN() from swallowing the condition
| git bisect good 65e9eb1ccfe56b41a0d8bfec651ea014968413cb
| # good: [c386e29d43728778ddd642fa73cc582bee684171] docs/rcu: Update the call_rcu() API
| git bisect good c386e29d43728778ddd642fa73cc582bee684171
| # good: [27c0f1448389baf7f309b69e62d4b531c9395e88] rcutorture: Make grace-period kthread report match RCU flavor being tested
| git bisect good 27c0f1448389baf7f309b69e62d4b531c9395e88
| # good: [3fcd6a230fa7d03bffcb831a81b40435c146c12b] x86/cpu: Avoid cpuinfo-induced IPIing of idle CPUs
| git bisect good 3fcd6a230fa7d03bffcb831a81b40435c146c12b
| # good: [75dc2da5ecd65bdcbfc4d59b9d9b7342c61fe374] rcu-tasks: Make the units of ->init_fract be jiffies
| git bisect good 75dc2da5ecd65bdcbfc4d59b9d9b7342c61fe374
| # first bad commit: [765b512bb3d639bfad7dd43c288ee085236c7267] Merge branches 'cpuinfo.2020.11.06a', 'doc.2020.11.06a', 'fixes.2020.11.02a', 'lockdep.2020.11.02a', 'tasks.2020.11.06a' and 'torture.2020.11.06a' into HEAD

This doesn't look very satisfying, given it's the merge commit. :-/

Quoted 6 lines

Quoted 4 lines
Failing that, please see the updated patch below. This adds a few more calls to lockdep_assert_irqs_disabled(), but perhaps more helpfully dumps the current stack of the CPU that the RCU grace-period kthread wants to run on in the case where this kthread has been starved of CPU.
Thanks, I will apply that after the bisection runs.

Here's a new log with it applied:

| [  118.480959] Key type dns_resolver registered
| [  118.487752] registered taskstats version 1
| [  118.489798] Running tests on all trace events:
| [  118.490164] Testing all events: OK
| [  173.304186] Running tests again, along with the function tracer
| [  173.320155] Running tests on all trace events:
| [  173.331638] Testing all events: 
| [  173.485044] hrtimer: interrupt took 14340976 ns
| [  334.160218] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 15s!
| [  334.259490] Showing busy workqueues and worker pools:
| [  334.265398] workqueue events: flags=0x0
| [  334.289070]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  334.300659]     pending: vmstat_shepherd
| [  453.541827] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!
| [  453.655731] BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 10s!
| [  453.759839] Showing busy workqueues and worker pools:
| [  453.784294] workqueue events: flags=0x0
| [  453.812207]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  453.822108]     pending: vmstat_shepherd
| [  453.839855] workqueue events_power_efficient: flags=0x82
| [  453.865152]   pwq 2: cpus=0 flags=0x4 nice=0 active=2/256 refcnt=4
| [  453.874553]     pending: neigh_periodic_work, do_cache_clean
| [  481.424362] BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 10s!
| [  481.508136] Showing busy workqueues and worker pools:
| [  481.524265] workqueue events: flags=0x0
| [  481.550480]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  481.560690]     pending: vmstat_shepherd
| [  481.571255] workqueue events_power_efficient: flags=0x82
| [  481.592515]   pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3
| [  481.601153]     pending: neigh_periodic_work
| [  532.108407] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!
| [  532.203476] Showing busy workqueues and worker pools:
| [  532.215930] workqueue events: flags=0x0
| [  532.244203]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  532.254428]     pending: vmstat_shepherd
| [  739.567892] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 19s!
| [  739.656419] Showing busy workqueues and worker pools:
| [  739.699514] workqueue events: flags=0x0
| [  739.705111]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  739.715393]     pending: vmstat_shepherd
| [  739.733403] workqueue events_power_efficient: flags=0x82
| [  739.739433]   pwq 2: cpus=0 flags=0x4 nice=0 active=2/256 refcnt=4
| [  739.748156]     pending: check_lifetime, neigh_periodic_work
| [  811.578165] BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 14s!
| [  811.602913] Showing busy workqueues and worker pools:
| [  811.620424] workqueue events: flags=0x0
| [  811.652479]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  811.662686]     pending: vmstat_shepherd
| [  811.683811] workqueue events_power_efficient: flags=0x82
| [  811.716123]   pwq 2: cpus=0 flags=0x5 nice=0 active=1/256 refcnt=3
| [  811.724857]     pending: neigh_periodic_work
| [  811.749989] pool 2: cpus=0 flags=0x5 nice=0 hung=14s workers=2 manager: 61 idle: 7
| [  822.456290] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 11s!
| [  822.600359] BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 25s!
| [  822.675814] Showing busy workqueues and worker pools:
| [  822.720098] workqueue events: flags=0x0
| [  822.747304]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  822.757174]     pending: vmstat_shepherd
| [  822.768047] workqueue events_power_efficient: flags=0x82
| [  822.799954]   pwq 2: cpus=0 flags=0x5 nice=0 active=1/256 refcnt=3
| [  822.808488]     pending: neigh_periodic_work
| [  822.831900] pool 2: cpus=0 flags=0x5 nice=0 hung=25s workers=2 manager: 61 idle: 7
| [  834.116239] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 22s!
| [  834.246557] BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 37s!
| [  834.271069] Showing busy workqueues and worker pools:
| [  834.276687] workqueue events: flags=0x0
| [  834.296267]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  834.306148]     pending: vmstat_shepherd
| [  834.324273] workqueue events_power_efficient: flags=0x82
| [  834.344433]   pwq 2: cpus=0 flags=0x5 nice=0 active=2/256 refcnt=4
| [  834.352891]     pending: neigh_periodic_work, do_cache_clean
| [  834.384530] pool 2: cpus=0 flags=0x5 nice=0 hung=37s workers=2 manager: 61 idle: 7
| [  840.906940] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
| [  840.912685] 	(detected by 0, t=3752 jiffies, g=2709, q=1)
| [  840.914587] rcu: All QSes seen, last rcu_preempt kthread activity 620 (4295099794-4295099174), jiffies_till_next_fqs=1, root ->qsmask 0x0
| [  840.925016] rcu: rcu_preempt kthread starved for 620 jiffies! g2709 f0x2 RCU_GP_CLEANUP(7) ->state=0x0 ->cpu=0
| [  840.930687] rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
| [  840.936056] rcu: RCU grace-period kthread stack dump:
| [  840.940433] task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
| [  840.949160] Call trace:
| [  840.952822]  dump_backtrace+0x0/0x278
| [  840.956816]  show_stack+0x30/0x80
| [  840.960643]  sched_show_task+0x1a8/0x240
| [  840.964684]  rcu_check_gp_kthread_starvation+0x170/0x358
| [  840.969113]  rcu_sched_clock_irq+0x744/0xd18
| [  840.973232]  update_process_times+0x68/0x98
| [  840.977308]  tick_sched_handle.isra.16+0x54/0x80
| [  840.981504]  tick_sched_timer+0x64/0xd8
| [  840.985500]  __hrtimer_run_queues+0x2a4/0x750
| [  840.989628]  hrtimer_interrupt+0xf4/0x2a0
| [  840.993669]  arch_timer_handler_virt+0x44/0x70
| [  840.997841]  handle_percpu_devid_irq+0xfc/0x4d0
| [  841.002043]  generic_handle_irq+0x50/0x70
| [  841.006098]  __handle_domain_irq+0x9c/0x120
| [  841.010188]  gic_handle_irq+0xcc/0x108
| [  841.014132]  el1_irq+0xbc/0x180
| [  841.017935]  arch_local_irq_restore+0x4/0x8
| [  841.021993]  trace_preempt_on+0xf4/0x190
| [  841.026016]  preempt_schedule_common+0x12c/0x1b0
| [  841.030193]  preempt_schedule.part.88+0x20/0x28
| [  841.034373]  preempt_schedule+0x20/0x28
| [  841.038369]  _raw_spin_unlock_irq+0x80/0x90
| [  841.042498]  rcu_gp_kthread+0xe5c/0x19a8
| [  841.046504]  kthread+0x174/0x188
| [  841.050320]  ret_from_fork+0x10/0x18
| [  841.054312] rcu: Stack dump where RCU grace-period kthread last ran:
| [  841.058980] Task dump for CPU 0:
| [  841.062736] task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
| [  841.071073] Call trace:
| [  841.074662]  dump_backtrace+0x0/0x278
| [  841.078596]  show_stack+0x30/0x80
| [  841.082386]  sched_show_task+0x1a8/0x240
| [  841.086367]  dump_cpu_task+0x48/0x58
| [  841.090311]  rcu_check_gp_kthread_starvation+0x214/0x358
| [  841.094736]  rcu_sched_clock_irq+0x744/0xd18
| [  841.098852]  update_process_times+0x68/0x98
| [  841.102949]  tick_sched_handle.isra.16+0x54/0x80
| [  841.107119]  tick_sched_timer+0x64/0xd8
| [  841.111127]  __hrtimer_run_queues+0x2a4/0x750
| [  841.115264]  hrtimer_interrupt+0xf4/0x2a0
| [  841.119319]  arch_timer_handler_virt+0x44/0x70
| [  841.123525]  handle_percpu_devid_irq+0xfc/0x4d0
| [  841.127690]  generic_handle_irq+0x50/0x70
| [  841.131702]  __handle_domain_irq+0x9c/0x120
| [  841.135779]  gic_handle_irq+0xcc/0x108
| [  841.139743]  el1_irq+0xbc/0x180
| [  841.143527]  arch_local_irq_restore+0x4/0x8
| [  841.147612]  trace_preempt_on+0xf4/0x190
| [  841.151656]  preempt_schedule_common+0x12c/0x1b0
| [  841.155869]  preempt_schedule.part.88+0x20/0x28
| [  841.160036]  preempt_schedule+0x20/0x28
| [  841.164051]  _raw_spin_unlock_irq+0x80/0x90
| [  841.168139]  rcu_gp_kthread+0xe5c/0x19a8
| [  841.172134]  kthread+0x174/0x188
| [  841.175953]  ret_from_fork+0x10/0x18
| [  841.191371] 
| [  841.193648] ================================
| [  841.196605] WARNING: inconsistent lock state
| [  841.199764] 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23 Not tainted
| [  841.203564] --------------------------------
| [  841.206550] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
| [  841.210074] rcu_preempt/10 [HC0[0]:SC0[0]:HE0:SE1] takes:
| [  841.213453] ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| [  841.221240] {IN-HARDIRQ-W} state was registered at:
| [  841.224538]   __lock_acquire+0x7bc/0x15b8
| [  841.227541]   lock_acquire+0x244/0x498
| [  841.230442]   _raw_spin_lock_irqsave+0x78/0x144
| [  841.233555]   rcu_sched_clock_irq+0x4a0/0xd18
| [  841.236621]   update_process_times+0x68/0x98
| [  841.239645]   tick_sched_handle.isra.16+0x54/0x80
| [  841.242801]   tick_sched_timer+0x64/0xd8
| [  841.245745]   __hrtimer_run_queues+0x2a4/0x750
| [  841.248842]   hrtimer_interrupt+0xf4/0x2a0
| [  841.251846]   arch_timer_handler_virt+0x44/0x70
| [  841.254976]   handle_percpu_devid_irq+0xfc/0x4d0
| [  841.258131]   generic_handle_irq+0x50/0x70
| [  841.261146]   __handle_domain_irq+0x9c/0x120
| [  841.264169]   gic_handle_irq+0xcc/0x108
| [  841.267096]   el1_irq+0xbc/0x180
| [  841.269844]   arch_local_irq_restore+0x4/0x8
| [  841.272881]   trace_preempt_on+0xf4/0x190
| [  841.275847]   preempt_schedule_common+0x12c/0x1b0
| [  841.279017]   preempt_schedule.part.88+0x20/0x28
| [  841.282149]   preempt_schedule+0x20/0x28
| [  841.285112]   _raw_spin_unlock_irq+0x80/0x90
| [  841.288154]   rcu_gp_kthread+0xe5c/0x19a8
| [  841.291175]   kthread+0x174/0x188
| [  841.293952]   ret_from_fork+0x10/0x18
| [  841.296780] irq event stamp: 39750
| [  841.299604] hardirqs last  enabled at (39749): [<ffffd787e6d85738>] rcu_irq_enter_irqson+0x48/0x68
| [  841.303961] hardirqs last disabled at (39750): [<ffffd787e6c122bc>] el1_irq+0x7c/0x180
| [  841.308042] softirqs last  enabled at (36704): [<ffffd787e6c10b58>] __do_softirq+0x650/0x6a4
| [  841.312250] softirqs last disabled at (36683): [<ffffd787e6cc0b80>] irq_exit+0x1a8/0x1b0
| [  841.316257] 
| [  841.316257] other info that might help us debug this:
| [  841.319834]  Possible unsafe locking scenario:
| [  841.319834] 
| [  841.323217]        CPU0
| [  841.325656]        ----
| [  841.328097]   lock(rcu_node_0);
| [  841.332433]   <Interrupt>
| [  841.334966]     lock(rcu_node_0);
| [  841.339379] 
| [  841.339379]  *** DEADLOCK ***
| [  841.339379] 
| [  841.342829] 1 lock held by rcu_preempt/10:
| [  841.345794]  #0: ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| [  841.354415] 
| [  841.354415] stack backtrace:
| [  841.357664] CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23
| [  841.362249] Hardware name: linux,dummy-virt (DT)
| [  841.365352] Call trace:
| [  841.367862]  dump_backtrace+0x0/0x278
| [  841.370745]  show_stack+0x30/0x80
| [  841.373517]  dump_stack+0x138/0x1b0
| [  841.376339]  print_usage_bug+0x2d8/0x2f8
| [  841.379288]  mark_lock.part.46+0x370/0x480
| [  841.382304]  mark_held_locks+0x58/0x90
| [  841.385228]  lockdep_hardirqs_on_prepare+0xdc/0x298
| [  841.388452]  trace_hardirqs_on+0x90/0x388
| [  841.391434]  el1_irq+0xd8/0x180
| [  841.394178]  arch_local_irq_restore+0x4/0x8
| [  841.397186]  trace_preempt_on+0xf4/0x190
| [  841.400127]  preempt_schedule_common+0x12c/0x1b0
| [  841.403246]  preempt_schedule.part.88+0x20/0x28
| [  841.406347]  preempt_schedule+0x20/0x28
| [  841.409278]  _raw_spin_unlock_irq+0x80/0x90
| [  841.412290]  rcu_gp_kthread+0xe5c/0x19a8
| [  841.415237]  kthread+0x174/0x188
| [  841.418011]  ret_from_fork+0x10/0x18
| [  841.423450] BUG: scheduling while atomic: rcu_preempt/10/0x00000002
| [  841.431367] INFO: lockdep is turned off.
| [  841.439132] Modules linked in:
| [  841.450608] Preemption disabled at:
| [  841.452261] [<ffffd787e7fffec0>] preempt_schedule.part.88+0x20/0x28
| [  841.467324] CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23
| [  841.471926] Hardware name: linux,dummy-virt (DT)
| [  841.475030] Call trace:
| [  841.477581]  dump_backtrace+0x0/0x278
| [  841.480451]  show_stack+0x30/0x80
| [  841.483220]  dump_stack+0x138/0x1b0
| [  841.486057]  __schedule_bug+0x8c/0xe8
| [  841.488949]  __schedule+0x7e8/0x890
| [  841.491801]  preempt_schedule_common+0x44/0x1b0
| [  841.494927]  preempt_schedule.part.88+0x20/0x28
| [  841.498048]  preempt_schedule+0x20/0x28
| [  841.500963]  _raw_spin_unlock_irq+0x80/0x90
| [  841.503988]  rcu_gp_kthread+0xe5c/0x19a8
| [  841.506965]  kthread+0x174/0x188
| [  841.509732]  ret_from_fork+0x10/0x18

Thanks,
-- Marco

Paul E. McKenney

maintainer

2020-11-12 17:54 UTC #14 lore raw

Quoted 23 lines · Marco Elver

Quoted 1 line · Marco Elver
On Thu, 12 Nov 2020 at 01:11, Paul E. McKenney <[email protected]> wrote:
[...]
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This assert didn't fire yet, I just get more of the below. I'll keep rerunning, but am not too hopeful...
Is bisection a possibility?
I've been running a bisection for past ~12h, and am making slow progress. It might be another 12h, but I think it'll get there.
Bisection gave me this:
| git bisect start
| # bad: [c07b306d7fa5680777e2132662d2e6c19fb53579] kfence: Avoid stalling work queue task without allocations
| git bisect bad c07b306d7fa5680777e2132662d2e6c19fb53579
| # good: [3cea11cd5e3b00d91caf0b4730194039b45c5891] Linux 5.10-rc2
| git bisect good 27598e7e73260ed0b2917eb02d4a515ebb578313
| # good: [3e5acbea719e66ef3be64fe74c99cc905ca697dc] Merge remote-tracking branch 'wireless-drivers-next/master' into master
| git bisect good 3e5acbea719e66ef3be64fe74c99cc905ca697dc
| # good: [491a5a9a2fea28353d99621b8abb83b6928b4e36] Merge remote-tracking branch 'sound-asoc/for-next' into master
| git bisect good 491a5a9a2fea28353d99621b8abb83b6928b4e36
| # bad: [502f8643d6e21c7e370a0b75131130cc51609055] Merge remote-tracking branch 'phy-next/next' into master

Quoted 8 lines

| git bisect bad 502f8643d6e21c7e370a0b75131130cc51609055
| # good: [6693cb1fa5ea7b91ec00f9404776a095713face5] Merge remote-tracking branch 'tip/auto-latest' into master
| git bisect good 6693cb1fa5ea7b91ec00f9404776a095713face5
| # bad: [b790e3afead9357195b6d1e1b6cd9b3521503ad2] Merge branch 'tglx-pc.2020.10.30a' into HEAD
| git bisect bad b790e3afead9357195b6d1e1b6cd9b3521503ad2
| # bad: [765b512bb3d639bfad7dd43c288ee085236c7267] Merge branches 'cpuinfo.2020.11.06a', 'doc.2020.11.06a', 'fixes.2020.11.02a', 'lockdep.2020.11.02a', 'tasks.2020.11.06a' and 'torture.2020.11.06a' into HEAD
| git bisect bad 765b512bb3d639bfad7dd43c288ee085236c7267
| # good: [01f9e708d9eae6335ae9ff25ab09893c20727a55] tools/rcutorture: Fix BUG parsing of console.log

So torture.2020.11.06a is OK.

Quoted 2 lines

| git bisect good 01f9e708d9eae6335ae9ff25ab09893c20727a55
| # good: [1be6ab91e2db157faedb7f16ab0636a80745a073] srcu: Take early exit on memory-allocation failure

As is fixes.2020.11.02a.

Quoted 2 lines

| git bisect good 1be6ab91e2db157faedb7f16ab0636a80745a073
| # good: [65e9eb1ccfe56b41a0d8bfec651ea014968413cb] rcu: Prevent RCU_LOCKDEP_WARN() from swallowing the condition

And lockdep.2020.11.02a.

Quoted 2 lines

| git bisect good 65e9eb1ccfe56b41a0d8bfec651ea014968413cb
| # good: [c386e29d43728778ddd642fa73cc582bee684171] docs/rcu: Update the call_rcu() API

And doc.2020.11.06a.

Quoted 2 lines

| git bisect good c386e29d43728778ddd642fa73cc582bee684171
| # good: [27c0f1448389baf7f309b69e62d4b531c9395e88] rcutorture: Make grace-period kthread report match RCU flavor being tested

And the first three commits of tasks.2020.11.06a.

Quoted 2 lines

| git bisect good 27c0f1448389baf7f309b69e62d4b531c9395e88
| # good: [3fcd6a230fa7d03bffcb831a81b40435c146c12b] x86/cpu: Avoid cpuinfo-induced IPIing of idle CPUs

And cpuinfo.2020.11.06a.

Quoted 2 lines

| git bisect good 3fcd6a230fa7d03bffcb831a81b40435c146c12b
| # good: [75dc2da5ecd65bdcbfc4d59b9d9b7342c61fe374] rcu-tasks: Make the units of ->init_fract be jiffies

And the remaining commit of tasks.2020.11.06a.

Quoted 4 lines

| git bisect good 75dc2da5ecd65bdcbfc4d59b9d9b7342c61fe374
| # first bad commit: [765b512bb3d639bfad7dd43c288ee085236c7267] Merge branches 'cpuinfo.2020.11.06a', 'doc.2020.11.06a', 'fixes.2020.11.02a', 'lockdep.2020.11.02a', 'tasks.2020.11.06a' and 'torture.2020.11.06a' into HEAD
This doesn't look very satisfying, given it's the merge commit. :-/

So each individual branch is just fine, but the merge of them is not. Fun.

These have been passing quite a bit of rcutorture over here, including preemptible kernels running !SMP, but admittedly on x86 rather than ARMv8.

One approach would be to binary-search the combinations of merges. Except that there are six of them, so there are 64 combinations, of which you have tested only 8 thus far (none, one each, and all).

But are you sure that the bisection points labeled "good" really are good? For example, what is the distribution of first failure times in the points labeled "bad" vs. the runtime used to make a "good" determination? Alternatively, just try a longer run on each of the commits feeding into the merge point.

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Failing that, please see the updated patch below. This adds a few more calls to lockdep_assert_irqs_disabled(), but perhaps more helpfully dumps the current stack of the CPU that the RCU grace-period kthread wants to run on in the case where this kthread has been starved of CPU.
Thanks, I will apply that after the bisection runs.
Here's a new log with it applied:

Even more strangeness! ;-)

Quoted 8 lines

| [  118.480959] Key type dns_resolver registered
| [  118.487752] registered taskstats version 1
| [  118.489798] Running tests on all trace events:
| [  118.490164] Testing all events: OK
| [  173.304186] Running tests again, along with the function tracer
| [  173.320155] Running tests on all trace events:
| [  173.331638] Testing all events: 
| [  173.485044] hrtimer: interrupt took 14340976 ns

Fourteen milliseconds, so annoying from a real-time perspective, but unlikely to be the cause of this.

Was the system responsive at this point, between three and ten minutes after boot? Similar question for the other gaps in the dmesg log. The reason for the question is that workqueue's reported stall times don't span these intervals.

Quoted 1 line

| [ 334.160218] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 15s!

It might be instructive to cause this code to provoke a backtrace. I suggest adding something like "trigger_single_cpu_backtrace(cpu)" in kernel/workqueue.c's function named wq_watchdog_timer_fn() somewhere within its "if" statement that is preceded with the "did we stall?" comment. Or just search for "BUG: workqueue lockup - pool" within kernel/workqueue.c.

Quoted 57 lines

| [  334.259490] Showing busy workqueues and worker pools:
| [  334.265398] workqueue events: flags=0x0
| [  334.289070]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  334.300659]     pending: vmstat_shepherd
| [  453.541827] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!
| [  453.655731] BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 10s!
| [  453.759839] Showing busy workqueues and worker pools:
| [  453.784294] workqueue events: flags=0x0
| [  453.812207]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  453.822108]     pending: vmstat_shepherd
| [  453.839855] workqueue events_power_efficient: flags=0x82
| [  453.865152]   pwq 2: cpus=0 flags=0x4 nice=0 active=2/256 refcnt=4
| [  453.874553]     pending: neigh_periodic_work, do_cache_clean
| [  481.424362] BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 10s!
| [  481.508136] Showing busy workqueues and worker pools:
| [  481.524265] workqueue events: flags=0x0
| [  481.550480]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  481.560690]     pending: vmstat_shepherd
| [  481.571255] workqueue events_power_efficient: flags=0x82
| [  481.592515]   pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3
| [  481.601153]     pending: neigh_periodic_work
| [  532.108407] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!
| [  532.203476] Showing busy workqueues and worker pools:
| [  532.215930] workqueue events: flags=0x0
| [  532.244203]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  532.254428]     pending: vmstat_shepherd
| [  739.567892] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 19s!
| [  739.656419] Showing busy workqueues and worker pools:
| [  739.699514] workqueue events: flags=0x0
| [  739.705111]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  739.715393]     pending: vmstat_shepherd
| [  739.733403] workqueue events_power_efficient: flags=0x82
| [  739.739433]   pwq 2: cpus=0 flags=0x4 nice=0 active=2/256 refcnt=4
| [  739.748156]     pending: check_lifetime, neigh_periodic_work
| [  811.578165] BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 14s!
| [  811.602913] Showing busy workqueues and worker pools:
| [  811.620424] workqueue events: flags=0x0
| [  811.652479]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  811.662686]     pending: vmstat_shepherd
| [  811.683811] workqueue events_power_efficient: flags=0x82
| [  811.716123]   pwq 2: cpus=0 flags=0x5 nice=0 active=1/256 refcnt=3
| [  811.724857]     pending: neigh_periodic_work
| [  811.749989] pool 2: cpus=0 flags=0x5 nice=0 hung=14s workers=2 manager: 61 idle: 7
| [  822.456290] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 11s!
| [  822.600359] BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 25s!
| [  822.675814] Showing busy workqueues and worker pools:
| [  822.720098] workqueue events: flags=0x0
| [  822.747304]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  822.757174]     pending: vmstat_shepherd
| [  822.768047] workqueue events_power_efficient: flags=0x82
| [  822.799954]   pwq 2: cpus=0 flags=0x5 nice=0 active=1/256 refcnt=3
| [  822.808488]     pending: neigh_periodic_work
| [  822.831900] pool 2: cpus=0 flags=0x5 nice=0 hung=25s workers=2 manager: 61 idle: 7
| [  834.116239] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 22s!
| [  834.246557] BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 37s!
| [  834.271069] Showing busy workqueues and worker pools:
| [  834.276687] workqueue events: flags=0x0

Quoted 8 lines

| [  834.296267]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  834.306148]     pending: vmstat_shepherd
| [  834.324273] workqueue events_power_efficient: flags=0x82
| [  834.344433]   pwq 2: cpus=0 flags=0x5 nice=0 active=2/256 refcnt=4
| [  834.352891]     pending: neigh_periodic_work, do_cache_clean
| [  834.384530] pool 2: cpus=0 flags=0x5 nice=0 hung=37s workers=2 manager: 61 idle: 7
| [  840.906940] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
| [  840.912685] 	(detected by 0, t=3752 jiffies, g=2709, q=1)

CPU 0 detected the stall.

Quoted 1 line

| [ 840.914587] rcu: All QSes seen, last rcu_preempt kthread activity 620 (4295099794-4295099174), jiffies_till_next_fqs=1, root ->qsmask 0x0

As before, the grace period is not stalled, but instead the grace-period kthread is failing to detect the end of an already-ended grace period.

Quoted 1 line

| [ 840.925016] rcu: rcu_preempt kthread starved for 620 jiffies! g2709 f0x2 RCU_GP_CLEANUP(7) ->state=0x0 ->cpu=0

And CPU 0 is where the RCU grace-period kthread was last seen running.

Quoted 24 lines

| [  840.930687] rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
| [  840.936056] rcu: RCU grace-period kthread stack dump:
| [  840.940433] task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
| [  840.949160] Call trace:
| [  840.952822]  dump_backtrace+0x0/0x278
| [  840.956816]  show_stack+0x30/0x80
| [  840.960643]  sched_show_task+0x1a8/0x240
| [  840.964684]  rcu_check_gp_kthread_starvation+0x170/0x358
| [  840.969113]  rcu_sched_clock_irq+0x744/0xd18
| [  840.973232]  update_process_times+0x68/0x98
| [  840.977308]  tick_sched_handle.isra.16+0x54/0x80
| [  840.981504]  tick_sched_timer+0x64/0xd8
| [  840.985500]  __hrtimer_run_queues+0x2a4/0x750
| [  840.989628]  hrtimer_interrupt+0xf4/0x2a0
| [  840.993669]  arch_timer_handler_virt+0x44/0x70
| [  840.997841]  handle_percpu_devid_irq+0xfc/0x4d0
| [  841.002043]  generic_handle_irq+0x50/0x70
| [  841.006098]  __handle_domain_irq+0x9c/0x120
| [  841.010188]  gic_handle_irq+0xcc/0x108
| [  841.014132]  el1_irq+0xbc/0x180
| [  841.017935]  arch_local_irq_restore+0x4/0x8
| [  841.021993]  trace_preempt_on+0xf4/0x190
| [  841.026016]  preempt_schedule_common+0x12c/0x1b0
| [  841.030193]  preempt_schedule.part.88+0x20/0x28

Quoted 8 lines

| [  841.034373]  preempt_schedule+0x20/0x28
| [  841.038369]  _raw_spin_unlock_irq+0x80/0x90
| [  841.042498]  rcu_gp_kthread+0xe5c/0x19a8
| [  841.046504]  kthread+0x174/0x188
| [  841.050320]  ret_from_fork+0x10/0x18
| [  841.054312] rcu: Stack dump where RCU grace-period kthread last ran:
| [  841.058980] Task dump for CPU 0:
| [  841.062736] task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428

And RCU's grace-period kthread really is running on CPU 0 right now. It is just not making any forward progress.

Quoted 10 lines

| [  841.071073] Call trace:
| [  841.074662]  dump_backtrace+0x0/0x278
| [  841.078596]  show_stack+0x30/0x80
| [  841.082386]  sched_show_task+0x1a8/0x240
| [  841.086367]  dump_cpu_task+0x48/0x58
| [  841.090311]  rcu_check_gp_kthread_starvation+0x214/0x358
| [  841.094736]  rcu_sched_clock_irq+0x744/0xd18
| [  841.098852]  update_process_times+0x68/0x98
| [  841.102949]  tick_sched_handle.isra.16+0x54/0x80
| [  841.107119]  tick_sched_timer+0x64/0xd8

Quoted 8 lines

| [  841.111127]  __hrtimer_run_queues+0x2a4/0x750
| [  841.115264]  hrtimer_interrupt+0xf4/0x2a0
| [  841.119319]  arch_timer_handler_virt+0x44/0x70
| [  841.123525]  handle_percpu_devid_irq+0xfc/0x4d0
| [  841.127690]  generic_handle_irq+0x50/0x70
| [  841.131702]  __handle_domain_irq+0x9c/0x120
| [  841.135779]  gic_handle_irq+0xcc/0x108
| [  841.139743]  el1_irq+0xbc/0x180

The code above this point was detecting and printing the RCU CPU stall warning. The code below this point was doing what?

Any chance of getting file names and line numbers for the rest of this stack?

Quoted 1 line

| [ 841.143527] arch_local_irq_restore+0x4/0x8

So we are just now restoring interrupts, hence our getting the interrupt at this point..

Quoted 1 line

| [ 841.147612] trace_preempt_on+0xf4/0x190

From within the trace code, which is apparently recording the fact that preemption is being enabled.

Quoted 3 lines

| [  841.151656]  preempt_schedule_common+0x12c/0x1b0
| [  841.155869]  preempt_schedule.part.88+0x20/0x28
| [  841.160036]  preempt_schedule+0x20/0x28

I was not aware that releasing a raw spinlock could result in a direct call to preempt_schedule().

Quoted 2 lines

| [  841.164051]  _raw_spin_unlock_irq+0x80/0x90
| [  841.168139]  rcu_gp_kthread+0xe5c/0x19a8

So the RCU grace-period kthread has spent many seconds attempting to release a lock? Am I reading this correctly? Mark Rutland, am I missing something here?

Quoted 7 lines

| [  841.172134]  kthread+0x174/0x188
| [  841.175953]  ret_from_fork+0x10/0x18
| [  841.191371] 
| [  841.193648] ================================
| [  841.196605] WARNING: inconsistent lock state
| [  841.199764] 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23 Not tainted
| [  841.203564] --------------------------------

Has lockdep recorded the fact that the lock is actually released? It had better, given that interrupts are now enabled.

Quoted 93 lines

| [  841.206550] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
| [  841.210074] rcu_preempt/10 [HC0[0]:SC0[0]:HE0:SE1] takes:
| [  841.213453] ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| [  841.221240] {IN-HARDIRQ-W} state was registered at:
| [  841.224538]   __lock_acquire+0x7bc/0x15b8
| [  841.227541]   lock_acquire+0x244/0x498
| [  841.230442]   _raw_spin_lock_irqsave+0x78/0x144
| [  841.233555]   rcu_sched_clock_irq+0x4a0/0xd18
| [  841.236621]   update_process_times+0x68/0x98
| [  841.239645]   tick_sched_handle.isra.16+0x54/0x80
| [  841.242801]   tick_sched_timer+0x64/0xd8
| [  841.245745]   __hrtimer_run_queues+0x2a4/0x750
| [  841.248842]   hrtimer_interrupt+0xf4/0x2a0
| [  841.251846]   arch_timer_handler_virt+0x44/0x70
| [  841.254976]   handle_percpu_devid_irq+0xfc/0x4d0
| [  841.258131]   generic_handle_irq+0x50/0x70
| [  841.261146]   __handle_domain_irq+0x9c/0x120
| [  841.264169]   gic_handle_irq+0xcc/0x108
| [  841.267096]   el1_irq+0xbc/0x180
| [  841.269844]   arch_local_irq_restore+0x4/0x8
| [  841.272881]   trace_preempt_on+0xf4/0x190
| [  841.275847]   preempt_schedule_common+0x12c/0x1b0
| [  841.279017]   preempt_schedule.part.88+0x20/0x28
| [  841.282149]   preempt_schedule+0x20/0x28
| [  841.285112]   _raw_spin_unlock_irq+0x80/0x90
| [  841.288154]   rcu_gp_kthread+0xe5c/0x19a8
| [  841.291175]   kthread+0x174/0x188
| [  841.293952]   ret_from_fork+0x10/0x18
| [  841.296780] irq event stamp: 39750
| [  841.299604] hardirqs last  enabled at (39749): [<ffffd787e6d85738>] rcu_irq_enter_irqson+0x48/0x68
| [  841.303961] hardirqs last disabled at (39750): [<ffffd787e6c122bc>] el1_irq+0x7c/0x180
| [  841.308042] softirqs last  enabled at (36704): [<ffffd787e6c10b58>] __do_softirq+0x650/0x6a4
| [  841.312250] softirqs last disabled at (36683): [<ffffd787e6cc0b80>] irq_exit+0x1a8/0x1b0
| [  841.316257] 
| [  841.316257] other info that might help us debug this:
| [  841.319834]  Possible unsafe locking scenario:
| [  841.319834] 
| [  841.323217]        CPU0
| [  841.325656]        ----
| [  841.328097]   lock(rcu_node_0);
| [  841.332433]   <Interrupt>
| [  841.334966]     lock(rcu_node_0);
| [  841.339379] 
| [  841.339379]  *** DEADLOCK ***
| [  841.339379] 
| [  841.342829] 1 lock held by rcu_preempt/10:
| [  841.345794]  #0: ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| [  841.354415] 
| [  841.354415] stack backtrace:
| [  841.357664] CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23
| [  841.362249] Hardware name: linux,dummy-virt (DT)
| [  841.365352] Call trace:
| [  841.367862]  dump_backtrace+0x0/0x278
| [  841.370745]  show_stack+0x30/0x80
| [  841.373517]  dump_stack+0x138/0x1b0
| [  841.376339]  print_usage_bug+0x2d8/0x2f8
| [  841.379288]  mark_lock.part.46+0x370/0x480
| [  841.382304]  mark_held_locks+0x58/0x90
| [  841.385228]  lockdep_hardirqs_on_prepare+0xdc/0x298
| [  841.388452]  trace_hardirqs_on+0x90/0x388
| [  841.391434]  el1_irq+0xd8/0x180
| [  841.394178]  arch_local_irq_restore+0x4/0x8
| [  841.397186]  trace_preempt_on+0xf4/0x190
| [  841.400127]  preempt_schedule_common+0x12c/0x1b0
| [  841.403246]  preempt_schedule.part.88+0x20/0x28
| [  841.406347]  preempt_schedule+0x20/0x28
| [  841.409278]  _raw_spin_unlock_irq+0x80/0x90
| [  841.412290]  rcu_gp_kthread+0xe5c/0x19a8
| [  841.415237]  kthread+0x174/0x188
| [  841.418011]  ret_from_fork+0x10/0x18
| [  841.423450] BUG: scheduling while atomic: rcu_preempt/10/0x00000002
| [  841.431367] INFO: lockdep is turned off.
| [  841.439132] Modules linked in:
| [  841.450608] Preemption disabled at:
| [  841.452261] [<ffffd787e7fffec0>] preempt_schedule.part.88+0x20/0x28
| [  841.467324] CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23
| [  841.471926] Hardware name: linux,dummy-virt (DT)
| [  841.475030] Call trace:
| [  841.477581]  dump_backtrace+0x0/0x278
| [  841.480451]  show_stack+0x30/0x80
| [  841.483220]  dump_stack+0x138/0x1b0
| [  841.486057]  __schedule_bug+0x8c/0xe8
| [  841.488949]  __schedule+0x7e8/0x890
| [  841.491801]  preempt_schedule_common+0x44/0x1b0
| [  841.494927]  preempt_schedule.part.88+0x20/0x28
| [  841.498048]  preempt_schedule+0x20/0x28
| [  841.500963]  _raw_spin_unlock_irq+0x80/0x90
| [  841.503988]  rcu_gp_kthread+0xe5c/0x19a8
| [  841.506965]  kthread+0x174/0x188
| [  841.509732]  ret_from_fork+0x10/0x18

Thanks,
-- Marco

Marco Elver

author maintainer

2020-11-12 18:13 UTC #15 lore raw

Quoted 68 lines · Paul E. McKenney

Quoted 23 lines · Marco Elver
Quoted 1 line · Marco Elver
On Thu, 12 Nov 2020 at 01:11, Paul E. McKenney <[email protected]> wrote:
[...]
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This assert didn't fire yet, I just get more of the below. I'll keep rerunning, but am not too hopeful...
Is bisection a possibility?
I've been running a bisection for past ~12h, and am making slow progress. It might be another 12h, but I think it'll get there.
Bisection gave me this:
| git bisect start
| # bad: [c07b306d7fa5680777e2132662d2e6c19fb53579] kfence: Avoid stalling work queue task without allocations
| git bisect bad c07b306d7fa5680777e2132662d2e6c19fb53579
| # good: [3cea11cd5e3b00d91caf0b4730194039b45c5891] Linux 5.10-rc2
| git bisect good 27598e7e73260ed0b2917eb02d4a515ebb578313
| # good: [3e5acbea719e66ef3be64fe74c99cc905ca697dc] Merge remote-tracking branch 'wireless-drivers-next/master' into master
| git bisect good 3e5acbea719e66ef3be64fe74c99cc905ca697dc
| # good: [491a5a9a2fea28353d99621b8abb83b6928b4e36] Merge remote-tracking branch 'sound-asoc/for-next' into master
| git bisect good 491a5a9a2fea28353d99621b8abb83b6928b4e36
| # bad: [502f8643d6e21c7e370a0b75131130cc51609055] Merge remote-tracking branch 'phy-next/next' into master
Quoted 8 lines
| git bisect bad 502f8643d6e21c7e370a0b75131130cc51609055
| # good: [6693cb1fa5ea7b91ec00f9404776a095713face5] Merge remote-tracking branch 'tip/auto-latest' into master
| git bisect good 6693cb1fa5ea7b91ec00f9404776a095713face5
| # bad: [b790e3afead9357195b6d1e1b6cd9b3521503ad2] Merge branch 'tglx-pc.2020.10.30a' into HEAD
| git bisect bad b790e3afead9357195b6d1e1b6cd9b3521503ad2
| # bad: [765b512bb3d639bfad7dd43c288ee085236c7267] Merge branches 'cpuinfo.2020.11.06a', 'doc.2020.11.06a', 'fixes.2020.11.02a', 'lockdep.2020.11.02a', 'tasks.2020.11.06a' and 'torture.2020.11.06a' into HEAD
| git bisect bad 765b512bb3d639bfad7dd43c288ee085236c7267
| # good: [01f9e708d9eae6335ae9ff25ab09893c20727a55] tools/rcutorture: Fix BUG parsing of console.log
So torture.2020.11.06a is OK.
Quoted 2 lines
| git bisect good 01f9e708d9eae6335ae9ff25ab09893c20727a55
| # good: [1be6ab91e2db157faedb7f16ab0636a80745a073] srcu: Take early exit on memory-allocation failure
As is fixes.2020.11.02a.
Quoted 2 lines
| git bisect good 1be6ab91e2db157faedb7f16ab0636a80745a073
| # good: [65e9eb1ccfe56b41a0d8bfec651ea014968413cb] rcu: Prevent RCU_LOCKDEP_WARN() from swallowing the condition
And lockdep.2020.11.02a.
Quoted 2 lines
| git bisect good 65e9eb1ccfe56b41a0d8bfec651ea014968413cb
| # good: [c386e29d43728778ddd642fa73cc582bee684171] docs/rcu: Update the call_rcu() API
And doc.2020.11.06a.
Quoted 2 lines
| git bisect good c386e29d43728778ddd642fa73cc582bee684171
| # good: [27c0f1448389baf7f309b69e62d4b531c9395e88] rcutorture: Make grace-period kthread report match RCU flavor being tested
And the first three commits of tasks.2020.11.06a.
Quoted 2 lines
| git bisect good 27c0f1448389baf7f309b69e62d4b531c9395e88
| # good: [3fcd6a230fa7d03bffcb831a81b40435c146c12b] x86/cpu: Avoid cpuinfo-induced IPIing of idle CPUs
And cpuinfo.2020.11.06a.
Quoted 2 lines
| git bisect good 3fcd6a230fa7d03bffcb831a81b40435c146c12b
| # good: [75dc2da5ecd65bdcbfc4d59b9d9b7342c61fe374] rcu-tasks: Make the units of ->init_fract be jiffies
And the remaining commit of tasks.2020.11.06a.
Quoted 3 lines
| git bisect good 75dc2da5ecd65bdcbfc4d59b9d9b7342c61fe374
| # first bad commit: [765b512bb3d639bfad7dd43c288ee085236c7267] Merge branches 'cpuinfo.2020.11.06a', 'doc.2020.11.06a', 'fixes.2020.11.02a', 'lockdep.2020.11.02a', 'tasks.2020.11.06a' and 'torture.2020.11.06a' into HEAD

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This doesn't look very satisfying, given it's the merge commit. :-/
So each individual branch is just fine, but the merge of them is not. Fun.
These have been passing quite a bit of rcutorture over here, including preemptible kernels running !SMP, but admittedly on x86 rather than ARMv8.

Note that this is ARMv8 on QEMU on an x86 host i.e. emulated. And it's really slow as a result. Together with a bunch of debug tools including lockdep.

Quoted 9 lines

One approach would be to binary-search the combinations of merges. Except that there are six of them, so there are 64 combinations, of which you have tested only 8 thus far (none, one each, and all).
But are you sure that the bisection points labeled "good" really are good? For example, what is the distribution of first failure times in the points labeled "bad" vs. the runtime used to make a "good" determination? Alternatively, just try a longer run on each of the commits feeding into the merge point.

Yeah, I'm having doubts, and this might be even more non-deterministic that I thought and some 'good' could maybe be 'bad' if I had re-run them? I don't know. One thing I can try is to make sure I run it more than once, but I'm definitely not doing that manually, so let me try and script something so I don't have to hand-hold the bisection overnight. :-)

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Failing that, please see the updated patch below. This adds a few more calls to lockdep_assert_irqs_disabled(), but perhaps more helpfully dumps the current stack of the CPU that the RCU grace-period kthread wants to run on in the case where this kthread has been starved of CPU.
Thanks, I will apply that after the bisection runs.
Here's a new log with it applied:
Even more strangeness! ;-)
Quoted 8 lines
| [  118.480959] Key type dns_resolver registered
| [  118.487752] registered taskstats version 1
| [  118.489798] Running tests on all trace events:
| [  118.490164] Testing all events: OK
| [  173.304186] Running tests again, along with the function tracer
| [  173.320155] Running tests on all trace events:
| [  173.331638] Testing all events: 
| [  173.485044] hrtimer: interrupt took 14340976 ns

Quoted 7 lines

Fourteen milliseconds, so annoying from a real-time perspective, but unlikely to be the cause of this.
Was the system responsive at this point, between three and ten minutes after boot? Similar question for the other gaps in the dmesg log. The reason for the question is that workqueue's reported stall times don't span these intervals.

The system is so slow at this point that I can't get much out of it either way, other than waiting and seeing if it proceeds...

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| [ 334.160218] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 15s!

Quoted 57 lines

| [  334.259490] Showing busy workqueues and worker pools:
| [  334.265398] workqueue events: flags=0x0
| [  334.289070]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  334.300659]     pending: vmstat_shepherd
| [  453.541827] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!
| [  453.655731] BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 10s!
| [  453.759839] Showing busy workqueues and worker pools:
| [  453.784294] workqueue events: flags=0x0
| [  453.812207]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  453.822108]     pending: vmstat_shepherd
| [  453.839855] workqueue events_power_efficient: flags=0x82
| [  453.865152]   pwq 2: cpus=0 flags=0x4 nice=0 active=2/256 refcnt=4
| [  453.874553]     pending: neigh_periodic_work, do_cache_clean
| [  481.424362] BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 10s!
| [  481.508136] Showing busy workqueues and worker pools:
| [  481.524265] workqueue events: flags=0x0
| [  481.550480]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  481.560690]     pending: vmstat_shepherd
| [  481.571255] workqueue events_power_efficient: flags=0x82
| [  481.592515]   pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3
| [  481.601153]     pending: neigh_periodic_work
| [  532.108407] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!
| [  532.203476] Showing busy workqueues and worker pools:
| [  532.215930] workqueue events: flags=0x0
| [  532.244203]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  532.254428]     pending: vmstat_shepherd
| [  739.567892] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 19s!
| [  739.656419] Showing busy workqueues and worker pools:
| [  739.699514] workqueue events: flags=0x0
| [  739.705111]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  739.715393]     pending: vmstat_shepherd
| [  739.733403] workqueue events_power_efficient: flags=0x82
| [  739.739433]   pwq 2: cpus=0 flags=0x4 nice=0 active=2/256 refcnt=4
| [  739.748156]     pending: check_lifetime, neigh_periodic_work
| [  811.578165] BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 14s!
| [  811.602913] Showing busy workqueues and worker pools:
| [  811.620424] workqueue events: flags=0x0
| [  811.652479]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  811.662686]     pending: vmstat_shepherd
| [  811.683811] workqueue events_power_efficient: flags=0x82
| [  811.716123]   pwq 2: cpus=0 flags=0x5 nice=0 active=1/256 refcnt=3
| [  811.724857]     pending: neigh_periodic_work
| [  811.749989] pool 2: cpus=0 flags=0x5 nice=0 hung=14s workers=2 manager: 61 idle: 7
| [  822.456290] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 11s!
| [  822.600359] BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 25s!
| [  822.675814] Showing busy workqueues and worker pools:
| [  822.720098] workqueue events: flags=0x0
| [  822.747304]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  822.757174]     pending: vmstat_shepherd
| [  822.768047] workqueue events_power_efficient: flags=0x82
| [  822.799954]   pwq 2: cpus=0 flags=0x5 nice=0 active=1/256 refcnt=3
| [  822.808488]     pending: neigh_periodic_work
| [  822.831900] pool 2: cpus=0 flags=0x5 nice=0 hung=25s workers=2 manager: 61 idle: 7
| [  834.116239] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 22s!
| [  834.246557] BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 37s!
| [  834.271069] Showing busy workqueues and worker pools:
| [  834.276687] workqueue events: flags=0x0

Quoted 8 lines

| [  834.296267]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  834.306148]     pending: vmstat_shepherd
| [  834.324273] workqueue events_power_efficient: flags=0x82
| [  834.344433]   pwq 2: cpus=0 flags=0x5 nice=0 active=2/256 refcnt=4
| [  834.352891]     pending: neigh_periodic_work, do_cache_clean
| [  834.384530] pool 2: cpus=0 flags=0x5 nice=0 hung=37s workers=2 manager: 61 idle: 7
| [  840.906940] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
| [  840.912685] 	(detected by 0, t=3752 jiffies, g=2709, q=1)

CPU 0 detected the stall.

Quoted 1 line

| [ 840.914587] rcu: All QSes seen, last rcu_preempt kthread activity 620 (4295099794-4295099174), jiffies_till_next_fqs=1, root ->qsmask 0x0

As before, the grace period is not stalled, but instead the grace-period kthread is failing to detect the end of an already-ended grace period.

Quoted 1 line

| [ 840.925016] rcu: rcu_preempt kthread starved for 620 jiffies! g2709 f0x2 RCU_GP_CLEANUP(7) ->state=0x0 ->cpu=0

And CPU 0 is where the RCU grace-period kthread was last seen running.

Quoted 24 lines

| [  840.930687] rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
| [  840.936056] rcu: RCU grace-period kthread stack dump:
| [  840.940433] task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
| [  840.949160] Call trace:
| [  840.952822]  dump_backtrace+0x0/0x278
| [  840.956816]  show_stack+0x30/0x80
| [  840.960643]  sched_show_task+0x1a8/0x240
| [  840.964684]  rcu_check_gp_kthread_starvation+0x170/0x358
| [  840.969113]  rcu_sched_clock_irq+0x744/0xd18
| [  840.973232]  update_process_times+0x68/0x98
| [  840.977308]  tick_sched_handle.isra.16+0x54/0x80
| [  840.981504]  tick_sched_timer+0x64/0xd8
| [  840.985500]  __hrtimer_run_queues+0x2a4/0x750
| [  840.989628]  hrtimer_interrupt+0xf4/0x2a0
| [  840.993669]  arch_timer_handler_virt+0x44/0x70
| [  840.997841]  handle_percpu_devid_irq+0xfc/0x4d0
| [  841.002043]  generic_handle_irq+0x50/0x70
| [  841.006098]  __handle_domain_irq+0x9c/0x120
| [  841.010188]  gic_handle_irq+0xcc/0x108
| [  841.014132]  el1_irq+0xbc/0x180
| [  841.017935]  arch_local_irq_restore+0x4/0x8
| [  841.021993]  trace_preempt_on+0xf4/0x190
| [  841.026016]  preempt_schedule_common+0x12c/0x1b0
| [  841.030193]  preempt_schedule.part.88+0x20/0x28

Quoted 8 lines

| [  841.034373]  preempt_schedule+0x20/0x28
| [  841.038369]  _raw_spin_unlock_irq+0x80/0x90
| [  841.042498]  rcu_gp_kthread+0xe5c/0x19a8
| [  841.046504]  kthread+0x174/0x188
| [  841.050320]  ret_from_fork+0x10/0x18
| [  841.054312] rcu: Stack dump where RCU grace-period kthread last ran:
| [  841.058980] Task dump for CPU 0:
| [  841.062736] task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428

And RCU's grace-period kthread really is running on CPU 0 right now. It is just not making any forward progress.

Quoted 10 lines

| [  841.071073] Call trace:
| [  841.074662]  dump_backtrace+0x0/0x278
| [  841.078596]  show_stack+0x30/0x80
| [  841.082386]  sched_show_task+0x1a8/0x240
| [  841.086367]  dump_cpu_task+0x48/0x58
| [  841.090311]  rcu_check_gp_kthread_starvation+0x214/0x358
| [  841.094736]  rcu_sched_clock_irq+0x744/0xd18
| [  841.098852]  update_process_times+0x68/0x98
| [  841.102949]  tick_sched_handle.isra.16+0x54/0x80
| [  841.107119]  tick_sched_timer+0x64/0xd8

Quoted 8 lines

| [  841.111127]  __hrtimer_run_queues+0x2a4/0x750
| [  841.115264]  hrtimer_interrupt+0xf4/0x2a0
| [  841.119319]  arch_timer_handler_virt+0x44/0x70
| [  841.123525]  handle_percpu_devid_irq+0xfc/0x4d0
| [  841.127690]  generic_handle_irq+0x50/0x70
| [  841.131702]  __handle_domain_irq+0x9c/0x120
| [  841.135779]  gic_handle_irq+0xcc/0x108
| [  841.139743]  el1_irq+0xbc/0x180

Quoted 5 lines

The code above this point was detecting and printing the RCU CPU stall warning. The code below this point was doing what?
Any chance of getting file names and line numbers for the rest of this stack?

I've attached a version of the log with line numbers.

Quoted 32 lines

Quoted 1 line
| [ 841.143527] arch_local_irq_restore+0x4/0x8
So we are just now restoring interrupts, hence our getting the interrupt at this point..
Quoted 1 line
| [ 841.147612] trace_preempt_on+0xf4/0x190
From within the trace code, which is apparently recording the fact that preemption is being enabled.
Quoted 3 lines
| [  841.151656]  preempt_schedule_common+0x12c/0x1b0
| [  841.155869]  preempt_schedule.part.88+0x20/0x28
| [  841.160036]  preempt_schedule+0x20/0x28
I was not aware that releasing a raw spinlock could result in a direct call to preempt_schedule().
Quoted 2 lines
| [  841.164051]  _raw_spin_unlock_irq+0x80/0x90
| [  841.168139]  rcu_gp_kthread+0xe5c/0x19a8
So the RCU grace-period kthread has spent many seconds attempting to release a lock? Am I reading this correctly? Mark Rutland, am I missing something here?
Quoted 7 lines
| [  841.172134]  kthread+0x174/0x188
| [  841.175953]  ret_from_fork+0x10/0x18
| [  841.191371] 
| [  841.193648] ================================
| [  841.196605] WARNING: inconsistent lock state
| [  841.199764] 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23 Not tainted
| [  841.203564] --------------------------------

Quoted 93 lines

Has lockdep recorded the fact that the lock is actually released? It had better, given that interrupts are now enabled.

Quoted 90 lines

| [  841.206550] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
| [  841.210074] rcu_preempt/10 [HC0[0]:SC0[0]:HE0:SE1] takes:
| [  841.213453] ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| [  841.221240] {IN-HARDIRQ-W} state was registered at:
| [  841.224538]   __lock_acquire+0x7bc/0x15b8
| [  841.227541]   lock_acquire+0x244/0x498
| [  841.230442]   _raw_spin_lock_irqsave+0x78/0x144
| [  841.233555]   rcu_sched_clock_irq+0x4a0/0xd18
| [  841.236621]   update_process_times+0x68/0x98
| [  841.239645]   tick_sched_handle.isra.16+0x54/0x80
| [  841.242801]   tick_sched_timer+0x64/0xd8
| [  841.245745]   __hrtimer_run_queues+0x2a4/0x750
| [  841.248842]   hrtimer_interrupt+0xf4/0x2a0
| [  841.251846]   arch_timer_handler_virt+0x44/0x70
| [  841.254976]   handle_percpu_devid_irq+0xfc/0x4d0
| [  841.258131]   generic_handle_irq+0x50/0x70
| [  841.261146]   __handle_domain_irq+0x9c/0x120
| [  841.264169]   gic_handle_irq+0xcc/0x108
| [  841.267096]   el1_irq+0xbc/0x180
| [  841.269844]   arch_local_irq_restore+0x4/0x8
| [  841.272881]   trace_preempt_on+0xf4/0x190
| [  841.275847]   preempt_schedule_common+0x12c/0x1b0
| [  841.279017]   preempt_schedule.part.88+0x20/0x28
| [  841.282149]   preempt_schedule+0x20/0x28
| [  841.285112]   _raw_spin_unlock_irq+0x80/0x90
| [  841.288154]   rcu_gp_kthread+0xe5c/0x19a8
| [  841.291175]   kthread+0x174/0x188
| [  841.293952]   ret_from_fork+0x10/0x18
| [  841.296780] irq event stamp: 39750
| [  841.299604] hardirqs last  enabled at (39749): [<ffffd787e6d85738>] rcu_irq_enter_irqson+0x48/0x68
| [  841.303961] hardirqs last disabled at (39750): [<ffffd787e6c122bc>] el1_irq+0x7c/0x180
| [  841.308042] softirqs last  enabled at (36704): [<ffffd787e6c10b58>] __do_softirq+0x650/0x6a4
| [  841.312250] softirqs last disabled at (36683): [<ffffd787e6cc0b80>] irq_exit+0x1a8/0x1b0
| [  841.316257] 
| [  841.316257] other info that might help us debug this:
| [  841.319834]  Possible unsafe locking scenario:
| [  841.319834] 
| [  841.323217]        CPU0
| [  841.325656]        ----
| [  841.328097]   lock(rcu_node_0);
| [  841.332433]   <Interrupt>
| [  841.334966]     lock(rcu_node_0);
| [  841.339379] 
| [  841.339379]  *** DEADLOCK ***
| [  841.339379] 
| [  841.342829] 1 lock held by rcu_preempt/10:
| [  841.345794]  #0: ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| [  841.354415] 
| [  841.354415] stack backtrace:
| [  841.357664] CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23
| [  841.362249] Hardware name: linux,dummy-virt (DT)
| [  841.365352] Call trace:
| [  841.367862]  dump_backtrace+0x0/0x278
| [  841.370745]  show_stack+0x30/0x80
| [  841.373517]  dump_stack+0x138/0x1b0
| [  841.376339]  print_usage_bug+0x2d8/0x2f8
| [  841.379288]  mark_lock.part.46+0x370/0x480
| [  841.382304]  mark_held_locks+0x58/0x90
| [  841.385228]  lockdep_hardirqs_on_prepare+0xdc/0x298
| [  841.388452]  trace_hardirqs_on+0x90/0x388
| [  841.391434]  el1_irq+0xd8/0x180
| [  841.394178]  arch_local_irq_restore+0x4/0x8
| [  841.397186]  trace_preempt_on+0xf4/0x190
| [  841.400127]  preempt_schedule_common+0x12c/0x1b0
| [  841.403246]  preempt_schedule.part.88+0x20/0x28
| [  841.406347]  preempt_schedule+0x20/0x28
| [  841.409278]  _raw_spin_unlock_irq+0x80/0x90
| [  841.412290]  rcu_gp_kthread+0xe5c/0x19a8
| [  841.415237]  kthread+0x174/0x188
| [  841.418011]  ret_from_fork+0x10/0x18
| [  841.423450] BUG: scheduling while atomic: rcu_preempt/10/0x00000002
| [  841.431367] INFO: lockdep is turned off.
| [  841.439132] Modules linked in:
| [  841.450608] Preemption disabled at:
| [  841.452261] [<ffffd787e7fffec0>] preempt_schedule.part.88+0x20/0x28
| [  841.467324] CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23
| [  841.471926] Hardware name: linux,dummy-virt (DT)
| [  841.475030] Call trace:
| [  841.477581]  dump_backtrace+0x0/0x278
| [  841.480451]  show_stack+0x30/0x80
| [  841.483220]  dump_stack+0x138/0x1b0
| [  841.486057]  __schedule_bug+0x8c/0xe8
| [  841.488949]  __schedule+0x7e8/0x890
| [  841.491801]  preempt_schedule_common+0x44/0x1b0
| [  841.494927]  preempt_schedule.part.88+0x20/0x28
| [  841.498048]  preempt_schedule+0x20/0x28
| [  841.500963]  _raw_spin_unlock_irq+0x80/0x90
| [  841.503988]  rcu_gp_kthread+0xe5c/0x19a8
| [  841.506965]  kthread+0x174/0x188
| [  841.509732]  ret_from_fork+0x10/0x18

Testing all events: OK
Running tests again, along with the function tracer Running tests on all trace events:
Testing all events:
hrtimer: interrupt took 14340976 ns

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 15s!

Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!
BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 10s!

BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 10s!

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!

Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 19s!

BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 14s!

Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd
workqueue events_power_efficient: flags=0x82
pwq 2: cpus=0 flags=0x5 nice=0 active=1/256 refcnt=3
pending: neigh_periodic_work
pool 2: cpus=0 flags=0x5 nice=0 hung=14s workers=2 manager: 61 idle: 7

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 11s!
BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 25s!

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 22s!
BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 37s!

Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd
workqueue events_power_efficient: flags=0x82
pwq 2: cpus=0 flags=0x5 nice=0 active=2/256 refcnt=4
pending: neigh_periodic_work, do_cache_clean
pool 2: cpus=0 flags=0x5 nice=0 hung=37s workers=2 manager: 61 idle: 7

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=3752 jiffies, g=2709, q=1)

rcu: All QSes seen, last rcu_preempt kthread activity 620 (4295099794-4295099174), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 620 jiffies! g2709 f0x2 RCU_GP_CLEANUP(7) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack: 0 pid: 10 ppid: 2 flags:0x00000428

Call trace:
 dump_backtrace+0x0/0x278 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x30/0x80 arch/arm64/kernel/stacktrace.c:196
 sched_show_task+0x1a8/0x240 kernel/sched/core.c:6445
 rcu_check_gp_kthread_starvation+0x170/0x358 kernel/rcu/tree_stall.h:469
 print_other_cpu_stall kernel/rcu/tree_stall.h:544 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:664 [inline]
 rcu_pending kernel/rcu/tree.c:3752 [inline]
 rcu_sched_clock_irq+0x744/0xd18 kernel/rcu/tree.c:2581
 update_process_times+0x68/0x98 kernel/time/timer.c:1709
 tick_sched_handle.isra.16+0x54/0x80 kernel/time/tick-sched.c:176
 tick_sched_timer+0x64/0xd8 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
 __hrtimer_run_queues+0x2a4/0x750 kernel/time/hrtimer.c:1583
 hrtimer_interrupt+0xf4/0x2a0 kernel/time/hrtimer.c:1645
 timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline]
 arch_timer_handler_virt+0x44/0x70 drivers/clocksource/arm_arch_timer.c:658
 handle_percpu_devid_irq+0xfc/0x4d0 kernel/irq/chip.c:930
 generic_handle_irq_desc include/linux/irqdesc.h:152 [inline]
 generic_handle_irq+0x50/0x70 kernel/irq/irqdesc.c:650
 __handle_domain_irq+0x9c/0x120 kernel/irq/irqdesc.c:687
 handle_domain_irq include/linux/irqdesc.h:170 [inline]
 gic_handle_irq+0xcc/0x108 drivers/irqchip/irq-gic.c:370
 el1_irq+0xbc/0x180 arch/arm64/kernel/entry.S:651
 arch_local_irq_restore+0x4/0x8 arch/arm64/include/asm/irqflags.h:124
 trace_preempt_enable_rcuidle include/trace/events/preemptirq.h:55 [inline]
 trace_preempt_on+0xf4/0x190 kernel/trace/trace_preemptirq.c:123
 preempt_latency_stop kernel/sched/core.c:4197 [inline]
 preempt_schedule_common+0x12c/0x1b0 kernel/sched/core.c:4682
 preempt_schedule.part.88+0x20/0x28 kernel/sched/core.c:4706
 preempt_schedule+0x20/0x28 kernel/sched/core.c:4707
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x80/0x90 kernel/locking/spinlock.c:199
 rcu_gp_cleanup kernel/rcu/tree.c:2046 [inline]
 rcu_gp_kthread+0xe5c/0x19a8 kernel/rcu/tree.c:2119
 kthread+0x174/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x18 arch/arm64/kernel/entry.S:961
rcu: Stack dump where RCU grace-period kthread last ran:
Task dump for CPU 0:
task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
Call trace:
 dump_backtrace+0x0/0x278 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x30/0x80 arch/arm64/kernel/stacktrace.c:196
 sched_show_task+0x1a8/0x240 kernel/sched/core.c:6445
 dump_cpu_task+0x48/0x58 kernel/sched/core.c:8428
 rcu_check_gp_kthread_starvation+0x214/0x358 kernel/rcu/tree_stall.h:474
 print_other_cpu_stall kernel/rcu/tree_stall.h:544 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:664 [inline]
 rcu_pending kernel/rcu/tree.c:3752 [inline]
 rcu_sched_clock_irq+0x744/0xd18 kernel/rcu/tree.c:2581
 update_process_times+0x68/0x98 kernel/time/timer.c:1709
 tick_sched_handle.isra.16+0x54/0x80 kernel/time/tick-sched.c:176
 tick_sched_timer+0x64/0xd8 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
 __hrtimer_run_queues+0x2a4/0x750 kernel/time/hrtimer.c:1583
 hrtimer_interrupt+0xf4/0x2a0 kernel/time/hrtimer.c:1645
 timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline]
 arch_timer_handler_virt+0x44/0x70 drivers/clocksource/arm_arch_timer.c:658
 handle_percpu_devid_irq+0xfc/0x4d0 kernel/irq/chip.c:930
 generic_handle_irq_desc include/linux/irqdesc.h:152 [inline]
 generic_handle_irq+0x50/0x70 kernel/irq/irqdesc.c:650
 __handle_domain_irq+0x9c/0x120 kernel/irq/irqdesc.c:687
 handle_domain_irq include/linux/irqdesc.h:170 [inline]
 gic_handle_irq+0xcc/0x108 drivers/irqchip/irq-gic.c:370
 el1_irq+0xbc/0x180 arch/arm64/kernel/entry.S:651
 arch_local_irq_restore+0x4/0x8 arch/arm64/include/asm/irqflags.h:124
 trace_preempt_enable_rcuidle include/trace/events/preemptirq.h:55 [inline]
 trace_preempt_on+0xf4/0x190 kernel/trace/trace_preemptirq.c:123
 preempt_latency_stop kernel/sched/core.c:4197 [inline]
 preempt_schedule_common+0x12c/0x1b0 kernel/sched/core.c:4682
 preempt_schedule.part.88+0x20/0x28 kernel/sched/core.c:4706
 preempt_schedule+0x20/0x28 kernel/sched/core.c:4707
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x80/0x90 kernel/locking/spinlock.c:199
 rcu_gp_cleanup kernel/rcu/tree.c:2046 [inline]
 rcu_gp_kthread+0xe5c/0x19a8 kernel/rcu/tree.c:2119
 kthread+0x174/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x18 arch/arm64/kernel/entry.S:961

================================
WARNING: inconsistent lock state
5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23 Not tainted
--------------------------------
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
rcu_preempt/10 [HC0[0]:SC0[0]:HE0:SE1] takes:
ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:505 [inline] ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:664 [inline] ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline] ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18 kernel/rcu/tree.c:2581 {IN-HARDIRQ-W} state was registered at:

  mark_lock kernel/locking/lockdep.c:4293 [inline]
  mark_usage kernel/locking/lockdep.c:4302 [inline]
  __lock_acquire+0x7bc/0x15b8 kernel/locking/lockdep.c:4785
  lock_acquire+0x244/0x498 kernel/locking/lockdep.c:5436
  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
  _raw_spin_lock_irqsave+0x78/0x144 kernel/locking/spinlock.c:159
  print_other_cpu_stall kernel/rcu/tree_stall.h:505 [inline]
  check_cpu_stall kernel/rcu/tree_stall.h:664 [inline]
  rcu_pending kernel/rcu/tree.c:3752 [inline]
  rcu_sched_clock_irq+0x4a0/0xd18 kernel/rcu/tree.c:2581
  update_process_times+0x68/0x98 kernel/time/timer.c:1709
  tick_sched_handle.isra.16+0x54/0x80 kernel/time/tick-sched.c:176
  tick_sched_timer+0x64/0xd8 kernel/time/tick-sched.c:1328
  __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
  __hrtimer_run_queues+0x2a4/0x750 kernel/time/hrtimer.c:1583
  hrtimer_interrupt+0xf4/0x2a0 kernel/time/hrtimer.c:1645
  timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline]
  arch_timer_handler_virt+0x44/0x70 drivers/clocksource/arm_arch_timer.c:658
  handle_percpu_devid_irq+0xfc/0x4d0 kernel/irq/chip.c:930
  generic_handle_irq_desc include/linux/irqdesc.h:152 [inline]
  generic_handle_irq+0x50/0x70 kernel/irq/irqdesc.c:650
  __handle_domain_irq+0x9c/0x120 kernel/irq/irqdesc.c:687
  handle_domain_irq include/linux/irqdesc.h:170 [inline]
  gic_handle_irq+0xcc/0x108 drivers/irqchip/irq-gic.c:370
  el1_irq+0xbc/0x180 arch/arm64/kernel/entry.S:651
  arch_local_irq_restore+0x4/0x8 arch/arm64/include/asm/irqflags.h:124
  trace_preempt_enable_rcuidle include/trace/events/preemptirq.h:55 [inline]
  trace_preempt_on+0xf4/0x190 kernel/trace/trace_preemptirq.c:123
  preempt_latency_stop kernel/sched/core.c:4197 [inline]
  preempt_schedule_common+0x12c/0x1b0 kernel/sched/core.c:4682
  preempt_schedule.part.88+0x20/0x28 kernel/sched/core.c:4706
  preempt_schedule+0x20/0x28 kernel/sched/core.c:4707
  __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
  _raw_spin_unlock_irq+0x80/0x90 kernel/locking/spinlock.c:199
  rcu_gp_cleanup kernel/rcu/tree.c:2046 [inline]
  rcu_gp_kthread+0xe5c/0x19a8 kernel/rcu/tree.c:2119
  kthread+0x174/0x188 kernel/kthread.c:292
  ret_from_fork+0x10/0x18 arch/arm64/kernel/entry.S:961
irq event stamp: 39750
hardirqs last  enabled at (39749): [<ffffd787e6d85738>] rcu_irq_enter_irqson+0x48/0x68 kernel/rcu/tree.c:1078
hardirqs last disabled at (39750): [<ffffd787e6c122bc>] el1_irq+0x7c/0x180 arch/arm64/kernel/entry.S:648
softirqs last  enabled at (36704): [<ffffd787e6c10b58>] __do_softirq+0x650/0x6a4 kernel/softirq.c:325
softirqs last disabled at (36683): [<ffffd787e6cc0b80>] do_softirq_own_stack include/linux/interrupt.h:568 [inline]
softirqs last disabled at (36683): [<ffffd787e6cc0b80>] invoke_softirq kernel/softirq.c:393 [inline]
softirqs last disabled at (36683): [<ffffd787e6cc0b80>] __irq_exit_rcu kernel/softirq.c:423 [inline]
softirqs last disabled at (36683): [<ffffd787e6cc0b80>] irq_exit+0x1a8/0x1b0 kernel/softirq.c:447

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0
       ----
  lock(rcu_node_0);
  <Interrupt>
    lock(rcu_node_0);

*** DEADLOCK ***

1 lock held by rcu_preempt/10:
#0: ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:505 [inline] #0: ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:664 [inline] #0: ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline] #0: ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18 kernel/rcu/tree.c:2581

stack backtrace:
CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x0/0x278 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x30/0x80 arch/arm64/kernel/stacktrace.c:196
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x138/0x1b0 lib/dump_stack.c:118
 print_usage_bug+0x2d8/0x2f8 kernel/locking/lockdep.c:3739
 valid_state kernel/locking/lockdep.c:3750 [inline]
 mark_lock_irq kernel/locking/lockdep.c:3953 [inline]
 mark_lock.part.46+0x370/0x480 kernel/locking/lockdep.c:4410
 mark_lock kernel/locking/lockdep.c:4008 [inline]
 mark_held_locks+0x58/0x90 kernel/locking/lockdep.c:4011
 __trace_hardirqs_on_caller kernel/locking/lockdep.c:4029 [inline]
 lockdep_hardirqs_on_prepare+0xdc/0x298 kernel/locking/lockdep.c:4097
 trace_hardirqs_on+0x90/0x388 kernel/trace/trace_preemptirq.c:49
 el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:685
 arch_local_irq_restore+0x4/0x8 arch/arm64/include/asm/irqflags.h:124
 trace_preempt_enable_rcuidle include/trace/events/preemptirq.h:55 [inline]
 trace_preempt_on+0xf4/0x190 kernel/trace/trace_preemptirq.c:123
 preempt_latency_stop kernel/sched/core.c:4197 [inline]
 preempt_schedule_common+0x12c/0x1b0 kernel/sched/core.c:4682
 preempt_schedule.part.88+0x20/0x28 kernel/sched/core.c:4706
 preempt_schedule+0x20/0x28 kernel/sched/core.c:4707
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x80/0x90 kernel/locking/spinlock.c:199
 rcu_gp_cleanup kernel/rcu/tree.c:2046 [inline]
 rcu_gp_kthread+0xe5c/0x19a8 kernel/rcu/tree.c:2119
 kthread+0x174/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x18 arch/arm64/kernel/entry.S:961
BUG: scheduling while atomic: rcu_preempt/10/0x00000002
INFO: lockdep is turned off.
Modules linked in:
Preemption disabled at:
[<ffffd787e7fffec0>] preempt_schedule.part.88+0x20/0x28 kernel/sched/core.c:4706
CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x0/0x278 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x30/0x80 arch/arm64/kernel/stacktrace.c:196
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x138/0x1b0 lib/dump_stack.c:118
 __schedule_bug+0x8c/0xe8 kernel/sched/core.c:4262
 schedule_debug kernel/sched/core.c:4289 [inline]
 __schedule+0x7e8/0x890 kernel/sched/core.c:4417
 preempt_schedule_common+0x44/0x1b0 kernel/sched/core.c:4681
 preempt_schedule.part.88+0x20/0x28 kernel/sched/core.c:4706
 preempt_schedule+0x20/0x28 kernel/sched/core.c:4707
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x80/0x90 kernel/locking/spinlock.c:199
 rcu_gp_cleanup kernel/rcu/tree.c:2046 [inline]
 rcu_gp_kthread+0xe5c/0x19a8 kernel/rcu/tree.c:2119
 kthread+0x174/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x18 arch/arm64/kernel/entry.S:961

Paul E. McKenney

maintainer

2020-11-12 20:00 UTC #16 lore raw

Quoted 71 lines · Marco Elver

Quoted 70 lines · Paul E. McKenney
Quoted 23 lines · Marco Elver
Quoted 1 line · Marco Elver
On Thu, 12 Nov 2020 at 01:11, Paul E. McKenney <[email protected]> wrote:
[...]
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This assert didn't fire yet, I just get more of the below. I'll keep rerunning, but am not too hopeful...
Is bisection a possibility?
I've been running a bisection for past ~12h, and am making slow progress. It might be another 12h, but I think it'll get there.
Bisection gave me this:
| git bisect start
| # bad: [c07b306d7fa5680777e2132662d2e6c19fb53579] kfence: Avoid stalling work queue task without allocations
| git bisect bad c07b306d7fa5680777e2132662d2e6c19fb53579
| # good: [3cea11cd5e3b00d91caf0b4730194039b45c5891] Linux 5.10-rc2
| git bisect good 27598e7e73260ed0b2917eb02d4a515ebb578313
| # good: [3e5acbea719e66ef3be64fe74c99cc905ca697dc] Merge remote-tracking branch 'wireless-drivers-next/master' into master
| git bisect good 3e5acbea719e66ef3be64fe74c99cc905ca697dc
| # good: [491a5a9a2fea28353d99621b8abb83b6928b4e36] Merge remote-tracking branch 'sound-asoc/for-next' into master
| git bisect good 491a5a9a2fea28353d99621b8abb83b6928b4e36
| # bad: [502f8643d6e21c7e370a0b75131130cc51609055] Merge remote-tracking branch 'phy-next/next' into master
Quoted 8 lines
| git bisect bad 502f8643d6e21c7e370a0b75131130cc51609055
| # good: [6693cb1fa5ea7b91ec00f9404776a095713face5] Merge remote-tracking branch 'tip/auto-latest' into master
| git bisect good 6693cb1fa5ea7b91ec00f9404776a095713face5
| # bad: [b790e3afead9357195b6d1e1b6cd9b3521503ad2] Merge branch 'tglx-pc.2020.10.30a' into HEAD
| git bisect bad b790e3afead9357195b6d1e1b6cd9b3521503ad2
| # bad: [765b512bb3d639bfad7dd43c288ee085236c7267] Merge branches 'cpuinfo.2020.11.06a', 'doc.2020.11.06a', 'fixes.2020.11.02a', 'lockdep.2020.11.02a', 'tasks.2020.11.06a' and 'torture.2020.11.06a' into HEAD
| git bisect bad 765b512bb3d639bfad7dd43c288ee085236c7267
| # good: [01f9e708d9eae6335ae9ff25ab09893c20727a55] tools/rcutorture: Fix BUG parsing of console.log
So torture.2020.11.06a is OK.
Quoted 2 lines
| git bisect good 01f9e708d9eae6335ae9ff25ab09893c20727a55
| # good: [1be6ab91e2db157faedb7f16ab0636a80745a073] srcu: Take early exit on memory-allocation failure
As is fixes.2020.11.02a.
Quoted 2 lines
| git bisect good 1be6ab91e2db157faedb7f16ab0636a80745a073
| # good: [65e9eb1ccfe56b41a0d8bfec651ea014968413cb] rcu: Prevent RCU_LOCKDEP_WARN() from swallowing the condition
And lockdep.2020.11.02a.
Quoted 2 lines
| git bisect good 65e9eb1ccfe56b41a0d8bfec651ea014968413cb
| # good: [c386e29d43728778ddd642fa73cc582bee684171] docs/rcu: Update the call_rcu() API
And doc.2020.11.06a.
Quoted 2 lines
| git bisect good c386e29d43728778ddd642fa73cc582bee684171
| # good: [27c0f1448389baf7f309b69e62d4b531c9395e88] rcutorture: Make grace-period kthread report match RCU flavor being tested
And the first three commits of tasks.2020.11.06a.
Quoted 2 lines
| git bisect good 27c0f1448389baf7f309b69e62d4b531c9395e88
| # good: [3fcd6a230fa7d03bffcb831a81b40435c146c12b] x86/cpu: Avoid cpuinfo-induced IPIing of idle CPUs
And cpuinfo.2020.11.06a.
Quoted 2 lines
| git bisect good 3fcd6a230fa7d03bffcb831a81b40435c146c12b
| # good: [75dc2da5ecd65bdcbfc4d59b9d9b7342c61fe374] rcu-tasks: Make the units of ->init_fract be jiffies
And the remaining commit of tasks.2020.11.06a.
Quoted 4 lines
| git bisect good 75dc2da5ecd65bdcbfc4d59b9d9b7342c61fe374
| # first bad commit: [765b512bb3d639bfad7dd43c288ee085236c7267] Merge branches 'cpuinfo.2020.11.06a', 'doc.2020.11.06a', 'fixes.2020.11.02a', 'lockdep.2020.11.02a', 'tasks.2020.11.06a' and 'torture.2020.11.06a' into HEAD
This doesn't look very satisfying, given it's the merge commit. :-/

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So each individual branch is just fine, but the merge of them is not. Fun.
These have been passing quite a bit of rcutorture over here, including preemptible kernels running !SMP, but admittedly on x86 rather than ARMv8.
Note that this is ARMv8 on QEMU on an x86 host i.e. emulated. And it's really slow as a result. Together with a bunch of debug tools including lockdep.

Then I don't envy you the bisection process! ;-)

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One approach would be to binary-search the combinations of merges. Except that there are six of them, so there are 64 combinations, of which you have tested only 8 thus far (none, one each, and all).
But are you sure that the bisection points labeled "good" really are good? For example, what is the distribution of first failure times in the points labeled "bad" vs. the runtime used to make a "good" determination? Alternatively, just try a longer run on each of the commits feeding into the merge point.

Quoted 6 lines

Yeah, I'm having doubts, and this might be even more non-deterministic that I thought and some 'good' could maybe be 'bad' if I had re-run them? I don't know. One thing I can try is to make sure I run it more than once, but I'm definitely not doing that manually, so let me try and script something so I don't have to hand-hold the bisection overnight. :-)

I know that feeling. A similar experience motivated me to upgrade my tooling, with more upgrades in the queue.

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Failing that, please see the updated patch below. This adds a few more calls to lockdep_assert_irqs_disabled(), but perhaps more helpfully dumps the current stack of the CPU that the RCU grace-period kthread wants to run on in the case where this kthread has been starved of CPU.
Thanks, I will apply that after the bisection runs.
Here's a new log with it applied:
Even more strangeness! ;-)
Quoted 8 lines
| [  118.480959] Key type dns_resolver registered
| [  118.487752] registered taskstats version 1
| [  118.489798] Running tests on all trace events:
| [  118.490164] Testing all events: OK
| [  173.304186] Running tests again, along with the function tracer
| [  173.320155] Running tests on all trace events:
| [  173.331638] Testing all events: 
| [  173.485044] hrtimer: interrupt took 14340976 ns
Fourteen milliseconds, so annoying from a real-time perspective, but unlikely to be the cause of this.

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Was the system responsive at this point, between three and ten minutes after boot? Similar question for the other gaps in the dmesg log. The reason for the question is that workqueue's reported stall times don't span these intervals.
The system is so slow at this point that I can't get much out of it either way, other than waiting and seeing if it proceeds...

Hey, I had to ask!

Quoted 141 lines

Quoted 1 line

| [ 334.160218] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 15s!

Quoted 57 lines

| [  334.259490] Showing busy workqueues and worker pools:
| [  334.265398] workqueue events: flags=0x0
| [  334.289070]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  334.300659]     pending: vmstat_shepherd
| [  453.541827] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!
| [  453.655731] BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 10s!
| [  453.759839] Showing busy workqueues and worker pools:
| [  453.784294] workqueue events: flags=0x0
| [  453.812207]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  453.822108]     pending: vmstat_shepherd
| [  453.839855] workqueue events_power_efficient: flags=0x82
| [  453.865152]   pwq 2: cpus=0 flags=0x4 nice=0 active=2/256 refcnt=4
| [  453.874553]     pending: neigh_periodic_work, do_cache_clean
| [  481.424362] BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 10s!
| [  481.508136] Showing busy workqueues and worker pools:
| [  481.524265] workqueue events: flags=0x0
| [  481.550480]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  481.560690]     pending: vmstat_shepherd
| [  481.571255] workqueue events_power_efficient: flags=0x82
| [  481.592515]   pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3
| [  481.601153]     pending: neigh_periodic_work
| [  532.108407] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!
| [  532.203476] Showing busy workqueues and worker pools:
| [  532.215930] workqueue events: flags=0x0
| [  532.244203]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  532.254428]     pending: vmstat_shepherd
| [  739.567892] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 19s!
| [  739.656419] Showing busy workqueues and worker pools:
| [  739.699514] workqueue events: flags=0x0
| [  739.705111]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  739.715393]     pending: vmstat_shepherd
| [  739.733403] workqueue events_power_efficient: flags=0x82
| [  739.739433]   pwq 2: cpus=0 flags=0x4 nice=0 active=2/256 refcnt=4
| [  739.748156]     pending: check_lifetime, neigh_periodic_work
| [  811.578165] BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 14s!
| [  811.602913] Showing busy workqueues and worker pools:
| [  811.620424] workqueue events: flags=0x0
| [  811.652479]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  811.662686]     pending: vmstat_shepherd
| [  811.683811] workqueue events_power_efficient: flags=0x82
| [  811.716123]   pwq 2: cpus=0 flags=0x5 nice=0 active=1/256 refcnt=3
| [  811.724857]     pending: neigh_periodic_work
| [  811.749989] pool 2: cpus=0 flags=0x5 nice=0 hung=14s workers=2 manager: 61 idle: 7
| [  822.456290] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 11s!
| [  822.600359] BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 25s!
| [  822.675814] Showing busy workqueues and worker pools:
| [  822.720098] workqueue events: flags=0x0
| [  822.747304]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  822.757174]     pending: vmstat_shepherd
| [  822.768047] workqueue events_power_efficient: flags=0x82
| [  822.799954]   pwq 2: cpus=0 flags=0x5 nice=0 active=1/256 refcnt=3
| [  822.808488]     pending: neigh_periodic_work
| [  822.831900] pool 2: cpus=0 flags=0x5 nice=0 hung=25s workers=2 manager: 61 idle: 7
| [  834.116239] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 22s!
| [  834.246557] BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 37s!
| [  834.271069] Showing busy workqueues and worker pools:
| [  834.276687] workqueue events: flags=0x0

Quoted 8 lines

| [  834.296267]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  834.306148]     pending: vmstat_shepherd
| [  834.324273] workqueue events_power_efficient: flags=0x82
| [  834.344433]   pwq 2: cpus=0 flags=0x5 nice=0 active=2/256 refcnt=4
| [  834.352891]     pending: neigh_periodic_work, do_cache_clean
| [  834.384530] pool 2: cpus=0 flags=0x5 nice=0 hung=37s workers=2 manager: 61 idle: 7
| [  840.906940] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
| [  840.912685] 	(detected by 0, t=3752 jiffies, g=2709, q=1)

CPU 0 detected the stall.

Quoted 1 line

| [ 840.914587] rcu: All QSes seen, last rcu_preempt kthread activity 620 (4295099794-4295099174), jiffies_till_next_fqs=1, root ->qsmask 0x0

As before, the grace period is not stalled, but instead the grace-period kthread is failing to detect the end of an already-ended grace period.

Quoted 1 line

| [ 840.925016] rcu: rcu_preempt kthread starved for 620 jiffies! g2709 f0x2 RCU_GP_CLEANUP(7) ->state=0x0 ->cpu=0

And CPU 0 is where the RCU grace-period kthread was last seen running.

Quoted 24 lines

| [  840.930687] rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
| [  840.936056] rcu: RCU grace-period kthread stack dump:
| [  840.940433] task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
| [  840.949160] Call trace:
| [  840.952822]  dump_backtrace+0x0/0x278
| [  840.956816]  show_stack+0x30/0x80
| [  840.960643]  sched_show_task+0x1a8/0x240
| [  840.964684]  rcu_check_gp_kthread_starvation+0x170/0x358
| [  840.969113]  rcu_sched_clock_irq+0x744/0xd18
| [  840.973232]  update_process_times+0x68/0x98
| [  840.977308]  tick_sched_handle.isra.16+0x54/0x80
| [  840.981504]  tick_sched_timer+0x64/0xd8
| [  840.985500]  __hrtimer_run_queues+0x2a4/0x750
| [  840.989628]  hrtimer_interrupt+0xf4/0x2a0
| [  840.993669]  arch_timer_handler_virt+0x44/0x70
| [  840.997841]  handle_percpu_devid_irq+0xfc/0x4d0
| [  841.002043]  generic_handle_irq+0x50/0x70
| [  841.006098]  __handle_domain_irq+0x9c/0x120
| [  841.010188]  gic_handle_irq+0xcc/0x108
| [  841.014132]  el1_irq+0xbc/0x180
| [  841.017935]  arch_local_irq_restore+0x4/0x8
| [  841.021993]  trace_preempt_on+0xf4/0x190
| [  841.026016]  preempt_schedule_common+0x12c/0x1b0
| [  841.030193]  preempt_schedule.part.88+0x20/0x28

Quoted 8 lines

| [  841.034373]  preempt_schedule+0x20/0x28
| [  841.038369]  _raw_spin_unlock_irq+0x80/0x90
| [  841.042498]  rcu_gp_kthread+0xe5c/0x19a8
| [  841.046504]  kthread+0x174/0x188
| [  841.050320]  ret_from_fork+0x10/0x18
| [  841.054312] rcu: Stack dump where RCU grace-period kthread last ran:
| [  841.058980] Task dump for CPU 0:
| [  841.062736] task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428

And RCU's grace-period kthread really is running on CPU 0 right now. It is just not making any forward progress.

Quoted 18 lines

| [  841.071073] Call trace:
| [  841.074662]  dump_backtrace+0x0/0x278
| [  841.078596]  show_stack+0x30/0x80
| [  841.082386]  sched_show_task+0x1a8/0x240
| [  841.086367]  dump_cpu_task+0x48/0x58
| [  841.090311]  rcu_check_gp_kthread_starvation+0x214/0x358
| [  841.094736]  rcu_sched_clock_irq+0x744/0xd18
| [  841.098852]  update_process_times+0x68/0x98
| [  841.102949]  tick_sched_handle.isra.16+0x54/0x80
| [  841.107119]  tick_sched_timer+0x64/0xd8
| [  841.111127]  __hrtimer_run_queues+0x2a4/0x750
| [  841.115264]  hrtimer_interrupt+0xf4/0x2a0
| [  841.119319]  arch_timer_handler_virt+0x44/0x70
| [  841.123525]  handle_percpu_devid_irq+0xfc/0x4d0
| [  841.127690]  generic_handle_irq+0x50/0x70
| [  841.131702]  __handle_domain_irq+0x9c/0x120
| [  841.135779]  gic_handle_irq+0xcc/0x108
| [  841.139743]  el1_irq+0xbc/0x180

Quoted 7 lines

Quoted 5 lines
The code above this point was detecting and printing the RCU CPU stall warning. The code below this point was doing what?
Any chance of getting file names and line numbers for the rest of this stack?
I've attached a version of the log with line numbers.

Thank you!

Quoted 17 lines

Quoted 17 lines
Quoted 1 line
| [ 841.143527] arch_local_irq_restore+0x4/0x8
So we are just now restoring interrupts, hence our getting the interrupt at this point..
Quoted 1 line
| [ 841.147612] trace_preempt_on+0xf4/0x190
From within the trace code, which is apparently recording the fact that preemption is being enabled.
Quoted 3 lines
| [  841.151656]  preempt_schedule_common+0x12c/0x1b0
| [  841.155869]  preempt_schedule.part.88+0x20/0x28
| [  841.160036]  preempt_schedule+0x20/0x28
I was not aware that releasing a raw spinlock could result in a direct call to preempt_schedule().

Quoted 6 lines

Quoted 6 lines
Quoted 2 lines
| [  841.164051]  _raw_spin_unlock_irq+0x80/0x90
| [  841.168139]  rcu_gp_kthread+0xe5c/0x19a8
So the RCU grace-period kthread has spent many seconds attempting to release a lock? Am I reading this correctly? Mark Rutland, am I missing something here?

And yes, this is the RCU grace-period kthread releasing a lock.

I have no idea why that would take so long. It is acting like a self-deadlock or similar hang, except that in that case, lockdep should have complained before the RCU CPU stall warning rather than after.

The only thing I can suggest is sprinkling lockdep_assert_irqs_disabled() calls hither and yon. All of the code that lockdep is complaining about runs in the context of the scheduling-clock interrupt, so interrupts had jolly well be disabled! ;-)

Rerunning some of the allegedly good bisects might be more productive.

Thanx, Paul

Quoted 387 lines

Quoted 8 lines

Quoted 7 lines

| [  841.172134]  kthread+0x174/0x188
| [  841.175953]  ret_from_fork+0x10/0x18
| [  841.191371] 
| [  841.193648] ================================
| [  841.196605] WARNING: inconsistent lock state
| [  841.199764] 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23 Not tainted
| [  841.203564] --------------------------------

Quoted 93 lines

Has lockdep recorded the fact that the lock is actually released? It had better, given that interrupts are now enabled.

Quoted 90 lines

| [  841.206550] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
| [  841.210074] rcu_preempt/10 [HC0[0]:SC0[0]:HE0:SE1] takes:
| [  841.213453] ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| [  841.221240] {IN-HARDIRQ-W} state was registered at:
| [  841.224538]   __lock_acquire+0x7bc/0x15b8
| [  841.227541]   lock_acquire+0x244/0x498
| [  841.230442]   _raw_spin_lock_irqsave+0x78/0x144
| [  841.233555]   rcu_sched_clock_irq+0x4a0/0xd18
| [  841.236621]   update_process_times+0x68/0x98
| [  841.239645]   tick_sched_handle.isra.16+0x54/0x80
| [  841.242801]   tick_sched_timer+0x64/0xd8
| [  841.245745]   __hrtimer_run_queues+0x2a4/0x750
| [  841.248842]   hrtimer_interrupt+0xf4/0x2a0
| [  841.251846]   arch_timer_handler_virt+0x44/0x70
| [  841.254976]   handle_percpu_devid_irq+0xfc/0x4d0
| [  841.258131]   generic_handle_irq+0x50/0x70
| [  841.261146]   __handle_domain_irq+0x9c/0x120
| [  841.264169]   gic_handle_irq+0xcc/0x108
| [  841.267096]   el1_irq+0xbc/0x180
| [  841.269844]   arch_local_irq_restore+0x4/0x8
| [  841.272881]   trace_preempt_on+0xf4/0x190
| [  841.275847]   preempt_schedule_common+0x12c/0x1b0
| [  841.279017]   preempt_schedule.part.88+0x20/0x28
| [  841.282149]   preempt_schedule+0x20/0x28
| [  841.285112]   _raw_spin_unlock_irq+0x80/0x90
| [  841.288154]   rcu_gp_kthread+0xe5c/0x19a8
| [  841.291175]   kthread+0x174/0x188
| [  841.293952]   ret_from_fork+0x10/0x18
| [  841.296780] irq event stamp: 39750
| [  841.299604] hardirqs last  enabled at (39749): [<ffffd787e6d85738>] rcu_irq_enter_irqson+0x48/0x68
| [  841.303961] hardirqs last disabled at (39750): [<ffffd787e6c122bc>] el1_irq+0x7c/0x180
| [  841.308042] softirqs last  enabled at (36704): [<ffffd787e6c10b58>] __do_softirq+0x650/0x6a4
| [  841.312250] softirqs last disabled at (36683): [<ffffd787e6cc0b80>] irq_exit+0x1a8/0x1b0
| [  841.316257] 
| [  841.316257] other info that might help us debug this:
| [  841.319834]  Possible unsafe locking scenario:
| [  841.319834] 
| [  841.323217]        CPU0
| [  841.325656]        ----
| [  841.328097]   lock(rcu_node_0);
| [  841.332433]   <Interrupt>
| [  841.334966]     lock(rcu_node_0);
| [  841.339379] 
| [  841.339379]  *** DEADLOCK ***
| [  841.339379] 
| [  841.342829] 1 lock held by rcu_preempt/10:
| [  841.345794]  #0: ffffd787e91d4358 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x4a0/0xd18
| [  841.354415] 
| [  841.354415] stack backtrace:
| [  841.357664] CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23
| [  841.362249] Hardware name: linux,dummy-virt (DT)
| [  841.365352] Call trace:
| [  841.367862]  dump_backtrace+0x0/0x278
| [  841.370745]  show_stack+0x30/0x80
| [  841.373517]  dump_stack+0x138/0x1b0
| [  841.376339]  print_usage_bug+0x2d8/0x2f8
| [  841.379288]  mark_lock.part.46+0x370/0x480
| [  841.382304]  mark_held_locks+0x58/0x90
| [  841.385228]  lockdep_hardirqs_on_prepare+0xdc/0x298
| [  841.388452]  trace_hardirqs_on+0x90/0x388
| [  841.391434]  el1_irq+0xd8/0x180
| [  841.394178]  arch_local_irq_restore+0x4/0x8
| [  841.397186]  trace_preempt_on+0xf4/0x190
| [  841.400127]  preempt_schedule_common+0x12c/0x1b0
| [  841.403246]  preempt_schedule.part.88+0x20/0x28
| [  841.406347]  preempt_schedule+0x20/0x28
| [  841.409278]  _raw_spin_unlock_irq+0x80/0x90
| [  841.412290]  rcu_gp_kthread+0xe5c/0x19a8
| [  841.415237]  kthread+0x174/0x188
| [  841.418011]  ret_from_fork+0x10/0x18
| [  841.423450] BUG: scheduling while atomic: rcu_preempt/10/0x00000002
| [  841.431367] INFO: lockdep is turned off.
| [  841.439132] Modules linked in:
| [  841.450608] Preemption disabled at:
| [  841.452261] [<ffffd787e7fffec0>] preempt_schedule.part.88+0x20/0x28
| [  841.467324] CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23
| [  841.471926] Hardware name: linux,dummy-virt (DT)
| [  841.475030] Call trace:
| [  841.477581]  dump_backtrace+0x0/0x278
| [  841.480451]  show_stack+0x30/0x80
| [  841.483220]  dump_stack+0x138/0x1b0
| [  841.486057]  __schedule_bug+0x8c/0xe8
| [  841.488949]  __schedule+0x7e8/0x890
| [  841.491801]  preempt_schedule_common+0x44/0x1b0
| [  841.494927]  preempt_schedule.part.88+0x20/0x28
| [  841.498048]  preempt_schedule+0x20/0x28
| [  841.500963]  _raw_spin_unlock_irq+0x80/0x90
| [  841.503988]  rcu_gp_kthread+0xe5c/0x19a8
| [  841.506965]  kthread+0x174/0x188
| [  841.509732]  ret_from_fork+0x10/0x18

Testing all events: OK
Running tests again, along with the function tracer Running tests on all trace events:
Testing all events:
hrtimer: interrupt took 14340976 ns

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 15s!

Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!
BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 10s!

BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 10s!

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!

Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 19s!

BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 14s!

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 11s!
BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 25s!

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 22s!
BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 37s!

Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd
workqueue events_power_efficient: flags=0x82
pwq 2: cpus=0 flags=0x5 nice=0 active=2/256 refcnt=4
pending: neigh_periodic_work, do_cache_clean
pool 2: cpus=0 flags=0x5 nice=0 hung=37s workers=2 manager: 61 idle: 7

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=3752 jiffies, g=2709, q=1)

Call trace:
 dump_backtrace+0x0/0x278 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x30/0x80 arch/arm64/kernel/stacktrace.c:196
 sched_show_task+0x1a8/0x240 kernel/sched/core.c:6445
 rcu_check_gp_kthread_starvation+0x170/0x358 kernel/rcu/tree_stall.h:469
 print_other_cpu_stall kernel/rcu/tree_stall.h:544 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:664 [inline]
 rcu_pending kernel/rcu/tree.c:3752 [inline]
 rcu_sched_clock_irq+0x744/0xd18 kernel/rcu/tree.c:2581
 update_process_times+0x68/0x98 kernel/time/timer.c:1709
 tick_sched_handle.isra.16+0x54/0x80 kernel/time/tick-sched.c:176
 tick_sched_timer+0x64/0xd8 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
 __hrtimer_run_queues+0x2a4/0x750 kernel/time/hrtimer.c:1583
 hrtimer_interrupt+0xf4/0x2a0 kernel/time/hrtimer.c:1645
 timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline]
 arch_timer_handler_virt+0x44/0x70 drivers/clocksource/arm_arch_timer.c:658
 handle_percpu_devid_irq+0xfc/0x4d0 kernel/irq/chip.c:930
 generic_handle_irq_desc include/linux/irqdesc.h:152 [inline]
 generic_handle_irq+0x50/0x70 kernel/irq/irqdesc.c:650
 __handle_domain_irq+0x9c/0x120 kernel/irq/irqdesc.c:687
 handle_domain_irq include/linux/irqdesc.h:170 [inline]
 gic_handle_irq+0xcc/0x108 drivers/irqchip/irq-gic.c:370
 el1_irq+0xbc/0x180 arch/arm64/kernel/entry.S:651
 arch_local_irq_restore+0x4/0x8 arch/arm64/include/asm/irqflags.h:124
 trace_preempt_enable_rcuidle include/trace/events/preemptirq.h:55 [inline]
 trace_preempt_on+0xf4/0x190 kernel/trace/trace_preemptirq.c:123
 preempt_latency_stop kernel/sched/core.c:4197 [inline]
 preempt_schedule_common+0x12c/0x1b0 kernel/sched/core.c:4682
 preempt_schedule.part.88+0x20/0x28 kernel/sched/core.c:4706
 preempt_schedule+0x20/0x28 kernel/sched/core.c:4707
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x80/0x90 kernel/locking/spinlock.c:199
 rcu_gp_cleanup kernel/rcu/tree.c:2046 [inline]
 rcu_gp_kthread+0xe5c/0x19a8 kernel/rcu/tree.c:2119
 kthread+0x174/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x18 arch/arm64/kernel/entry.S:961
rcu: Stack dump where RCU grace-period kthread last ran:
Task dump for CPU 0:
task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
Call trace:
 dump_backtrace+0x0/0x278 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x30/0x80 arch/arm64/kernel/stacktrace.c:196
 sched_show_task+0x1a8/0x240 kernel/sched/core.c:6445
 dump_cpu_task+0x48/0x58 kernel/sched/core.c:8428
 rcu_check_gp_kthread_starvation+0x214/0x358 kernel/rcu/tree_stall.h:474
 print_other_cpu_stall kernel/rcu/tree_stall.h:544 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:664 [inline]
 rcu_pending kernel/rcu/tree.c:3752 [inline]
 rcu_sched_clock_irq+0x744/0xd18 kernel/rcu/tree.c:2581
 update_process_times+0x68/0x98 kernel/time/timer.c:1709
 tick_sched_handle.isra.16+0x54/0x80 kernel/time/tick-sched.c:176
 tick_sched_timer+0x64/0xd8 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
 __hrtimer_run_queues+0x2a4/0x750 kernel/time/hrtimer.c:1583
 hrtimer_interrupt+0xf4/0x2a0 kernel/time/hrtimer.c:1645
 timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline]
 arch_timer_handler_virt+0x44/0x70 drivers/clocksource/arm_arch_timer.c:658
 handle_percpu_devid_irq+0xfc/0x4d0 kernel/irq/chip.c:930
 generic_handle_irq_desc include/linux/irqdesc.h:152 [inline]
 generic_handle_irq+0x50/0x70 kernel/irq/irqdesc.c:650
 __handle_domain_irq+0x9c/0x120 kernel/irq/irqdesc.c:687
 handle_domain_irq include/linux/irqdesc.h:170 [inline]
 gic_handle_irq+0xcc/0x108 drivers/irqchip/irq-gic.c:370
 el1_irq+0xbc/0x180 arch/arm64/kernel/entry.S:651
 arch_local_irq_restore+0x4/0x8 arch/arm64/include/asm/irqflags.h:124
 trace_preempt_enable_rcuidle include/trace/events/preemptirq.h:55 [inline]
 trace_preempt_on+0xf4/0x190 kernel/trace/trace_preemptirq.c:123
 preempt_latency_stop kernel/sched/core.c:4197 [inline]
 preempt_schedule_common+0x12c/0x1b0 kernel/sched/core.c:4682
 preempt_schedule.part.88+0x20/0x28 kernel/sched/core.c:4706
 preempt_schedule+0x20/0x28 kernel/sched/core.c:4707
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x80/0x90 kernel/locking/spinlock.c:199
 rcu_gp_cleanup kernel/rcu/tree.c:2046 [inline]
 rcu_gp_kthread+0xe5c/0x19a8 kernel/rcu/tree.c:2119
 kthread+0x174/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x18 arch/arm64/kernel/entry.S:961

  mark_lock kernel/locking/lockdep.c:4293 [inline]
  mark_usage kernel/locking/lockdep.c:4302 [inline]
  __lock_acquire+0x7bc/0x15b8 kernel/locking/lockdep.c:4785
  lock_acquire+0x244/0x498 kernel/locking/lockdep.c:5436
  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
  _raw_spin_lock_irqsave+0x78/0x144 kernel/locking/spinlock.c:159
  print_other_cpu_stall kernel/rcu/tree_stall.h:505 [inline]
  check_cpu_stall kernel/rcu/tree_stall.h:664 [inline]
  rcu_pending kernel/rcu/tree.c:3752 [inline]
  rcu_sched_clock_irq+0x4a0/0xd18 kernel/rcu/tree.c:2581
  update_process_times+0x68/0x98 kernel/time/timer.c:1709
  tick_sched_handle.isra.16+0x54/0x80 kernel/time/tick-sched.c:176
  tick_sched_timer+0x64/0xd8 kernel/time/tick-sched.c:1328
  __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
  __hrtimer_run_queues+0x2a4/0x750 kernel/time/hrtimer.c:1583
  hrtimer_interrupt+0xf4/0x2a0 kernel/time/hrtimer.c:1645
  timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline]
  arch_timer_handler_virt+0x44/0x70 drivers/clocksource/arm_arch_timer.c:658
  handle_percpu_devid_irq+0xfc/0x4d0 kernel/irq/chip.c:930
  generic_handle_irq_desc include/linux/irqdesc.h:152 [inline]
  generic_handle_irq+0x50/0x70 kernel/irq/irqdesc.c:650
  __handle_domain_irq+0x9c/0x120 kernel/irq/irqdesc.c:687
  handle_domain_irq include/linux/irqdesc.h:170 [inline]
  gic_handle_irq+0xcc/0x108 drivers/irqchip/irq-gic.c:370
  el1_irq+0xbc/0x180 arch/arm64/kernel/entry.S:651
  arch_local_irq_restore+0x4/0x8 arch/arm64/include/asm/irqflags.h:124
  trace_preempt_enable_rcuidle include/trace/events/preemptirq.h:55 [inline]
  trace_preempt_on+0xf4/0x190 kernel/trace/trace_preemptirq.c:123
  preempt_latency_stop kernel/sched/core.c:4197 [inline]
  preempt_schedule_common+0x12c/0x1b0 kernel/sched/core.c:4682
  preempt_schedule.part.88+0x20/0x28 kernel/sched/core.c:4706
  preempt_schedule+0x20/0x28 kernel/sched/core.c:4707
  __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
  _raw_spin_unlock_irq+0x80/0x90 kernel/locking/spinlock.c:199
  rcu_gp_cleanup kernel/rcu/tree.c:2046 [inline]
  rcu_gp_kthread+0xe5c/0x19a8 kernel/rcu/tree.c:2119
  kthread+0x174/0x188 kernel/kthread.c:292
  ret_from_fork+0x10/0x18 arch/arm64/kernel/entry.S:961
irq event stamp: 39750
hardirqs last  enabled at (39749): [<ffffd787e6d85738>] rcu_irq_enter_irqson+0x48/0x68 kernel/rcu/tree.c:1078
hardirqs last disabled at (39750): [<ffffd787e6c122bc>] el1_irq+0x7c/0x180 arch/arm64/kernel/entry.S:648
softirqs last  enabled at (36704): [<ffffd787e6c10b58>] __do_softirq+0x650/0x6a4 kernel/softirq.c:325
softirqs last disabled at (36683): [<ffffd787e6cc0b80>] do_softirq_own_stack include/linux/interrupt.h:568 [inline]
softirqs last disabled at (36683): [<ffffd787e6cc0b80>] invoke_softirq kernel/softirq.c:393 [inline]
softirqs last disabled at (36683): [<ffffd787e6cc0b80>] __irq_exit_rcu kernel/softirq.c:423 [inline]
softirqs last disabled at (36683): [<ffffd787e6cc0b80>] irq_exit+0x1a8/0x1b0 kernel/softirq.c:447

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0
       ----
  lock(rcu_node_0);
  <Interrupt>
    lock(rcu_node_0);

*** DEADLOCK ***

stack backtrace:
CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x0/0x278 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x30/0x80 arch/arm64/kernel/stacktrace.c:196
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x138/0x1b0 lib/dump_stack.c:118
 print_usage_bug+0x2d8/0x2f8 kernel/locking/lockdep.c:3739
 valid_state kernel/locking/lockdep.c:3750 [inline]
 mark_lock_irq kernel/locking/lockdep.c:3953 [inline]
 mark_lock.part.46+0x370/0x480 kernel/locking/lockdep.c:4410
 mark_lock kernel/locking/lockdep.c:4008 [inline]
 mark_held_locks+0x58/0x90 kernel/locking/lockdep.c:4011
 __trace_hardirqs_on_caller kernel/locking/lockdep.c:4029 [inline]
 lockdep_hardirqs_on_prepare+0xdc/0x298 kernel/locking/lockdep.c:4097
 trace_hardirqs_on+0x90/0x388 kernel/trace/trace_preemptirq.c:49
 el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:685
 arch_local_irq_restore+0x4/0x8 arch/arm64/include/asm/irqflags.h:124
 trace_preempt_enable_rcuidle include/trace/events/preemptirq.h:55 [inline]
 trace_preempt_on+0xf4/0x190 kernel/trace/trace_preemptirq.c:123
 preempt_latency_stop kernel/sched/core.c:4197 [inline]
 preempt_schedule_common+0x12c/0x1b0 kernel/sched/core.c:4682
 preempt_schedule.part.88+0x20/0x28 kernel/sched/core.c:4706
 preempt_schedule+0x20/0x28 kernel/sched/core.c:4707
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x80/0x90 kernel/locking/spinlock.c:199
 rcu_gp_cleanup kernel/rcu/tree.c:2046 [inline]
 rcu_gp_kthread+0xe5c/0x19a8 kernel/rcu/tree.c:2119
 kthread+0x174/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x18 arch/arm64/kernel/entry.S:961
BUG: scheduling while atomic: rcu_preempt/10/0x00000002
INFO: lockdep is turned off.
Modules linked in:
Preemption disabled at:
[<ffffd787e7fffec0>] preempt_schedule.part.88+0x20/0x28 kernel/sched/core.c:4706
CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #23
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x0/0x278 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x30/0x80 arch/arm64/kernel/stacktrace.c:196
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x138/0x1b0 lib/dump_stack.c:118
 __schedule_bug+0x8c/0xe8 kernel/sched/core.c:4262
 schedule_debug kernel/sched/core.c:4289 [inline]
 __schedule+0x7e8/0x890 kernel/sched/core.c:4417
 preempt_schedule_common+0x44/0x1b0 kernel/sched/core.c:4681
 preempt_schedule.part.88+0x20/0x28 kernel/sched/core.c:4706
 preempt_schedule+0x20/0x28 kernel/sched/core.c:4707
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x80/0x90 kernel/locking/spinlock.c:199
 rcu_gp_cleanup kernel/rcu/tree.c:2046 [inline]
 rcu_gp_kthread+0xe5c/0x19a8 kernel/rcu/tree.c:2119
 kthread+0x174/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x18 arch/arm64/kernel/entry.S:961

Marco Elver

author maintainer

2020-11-13 11:06 UTC #17 lore raw

Quoted 102 lines · Paul E. McKenney

Quoted 71 lines · Marco Elver
Quoted 70 lines · Paul E. McKenney
Quoted 23 lines · Marco Elver
Quoted 1 line · Marco Elver
On Thu, 12 Nov 2020 at 01:11, Paul E. McKenney <[email protected]> wrote:
[...]
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This assert didn't fire yet, I just get more of the below. I'll keep rerunning, but am not too hopeful...
Is bisection a possibility?
I've been running a bisection for past ~12h, and am making slow progress. It might be another 12h, but I think it'll get there.
Bisection gave me this:
| git bisect start
| # bad: [c07b306d7fa5680777e2132662d2e6c19fb53579] kfence: Avoid stalling work queue task without allocations
| git bisect bad c07b306d7fa5680777e2132662d2e6c19fb53579
| # good: [3cea11cd5e3b00d91caf0b4730194039b45c5891] Linux 5.10-rc2
| git bisect good 27598e7e73260ed0b2917eb02d4a515ebb578313
| # good: [3e5acbea719e66ef3be64fe74c99cc905ca697dc] Merge remote-tracking branch 'wireless-drivers-next/master' into master
| git bisect good 3e5acbea719e66ef3be64fe74c99cc905ca697dc
| # good: [491a5a9a2fea28353d99621b8abb83b6928b4e36] Merge remote-tracking branch 'sound-asoc/for-next' into master
| git bisect good 491a5a9a2fea28353d99621b8abb83b6928b4e36
| # bad: [502f8643d6e21c7e370a0b75131130cc51609055] Merge remote-tracking branch 'phy-next/next' into master
Quoted 8 lines
| git bisect bad 502f8643d6e21c7e370a0b75131130cc51609055
| # good: [6693cb1fa5ea7b91ec00f9404776a095713face5] Merge remote-tracking branch 'tip/auto-latest' into master
| git bisect good 6693cb1fa5ea7b91ec00f9404776a095713face5
| # bad: [b790e3afead9357195b6d1e1b6cd9b3521503ad2] Merge branch 'tglx-pc.2020.10.30a' into HEAD
| git bisect bad b790e3afead9357195b6d1e1b6cd9b3521503ad2
| # bad: [765b512bb3d639bfad7dd43c288ee085236c7267] Merge branches 'cpuinfo.2020.11.06a', 'doc.2020.11.06a', 'fixes.2020.11.02a', 'lockdep.2020.11.02a', 'tasks.2020.11.06a' and 'torture.2020.11.06a' into HEAD
| git bisect bad 765b512bb3d639bfad7dd43c288ee085236c7267
| # good: [01f9e708d9eae6335ae9ff25ab09893c20727a55] tools/rcutorture: Fix BUG parsing of console.log
So torture.2020.11.06a is OK.
Quoted 2 lines
| git bisect good 01f9e708d9eae6335ae9ff25ab09893c20727a55
| # good: [1be6ab91e2db157faedb7f16ab0636a80745a073] srcu: Take early exit on memory-allocation failure
As is fixes.2020.11.02a.
Quoted 2 lines
| git bisect good 1be6ab91e2db157faedb7f16ab0636a80745a073
| # good: [65e9eb1ccfe56b41a0d8bfec651ea014968413cb] rcu: Prevent RCU_LOCKDEP_WARN() from swallowing the condition
And lockdep.2020.11.02a.
Quoted 2 lines
| git bisect good 65e9eb1ccfe56b41a0d8bfec651ea014968413cb
| # good: [c386e29d43728778ddd642fa73cc582bee684171] docs/rcu: Update the call_rcu() API
And doc.2020.11.06a.
Quoted 2 lines
| git bisect good c386e29d43728778ddd642fa73cc582bee684171
| # good: [27c0f1448389baf7f309b69e62d4b531c9395e88] rcutorture: Make grace-period kthread report match RCU flavor being tested
And the first three commits of tasks.2020.11.06a.
Quoted 2 lines
| git bisect good 27c0f1448389baf7f309b69e62d4b531c9395e88
| # good: [3fcd6a230fa7d03bffcb831a81b40435c146c12b] x86/cpu: Avoid cpuinfo-induced IPIing of idle CPUs
And cpuinfo.2020.11.06a.
Quoted 2 lines
| git bisect good 3fcd6a230fa7d03bffcb831a81b40435c146c12b
| # good: [75dc2da5ecd65bdcbfc4d59b9d9b7342c61fe374] rcu-tasks: Make the units of ->init_fract be jiffies
And the remaining commit of tasks.2020.11.06a.
Quoted 4 lines
| git bisect good 75dc2da5ecd65bdcbfc4d59b9d9b7342c61fe374
| # first bad commit: [765b512bb3d639bfad7dd43c288ee085236c7267] Merge branches 'cpuinfo.2020.11.06a', 'doc.2020.11.06a', 'fixes.2020.11.02a', 'lockdep.2020.11.02a', 'tasks.2020.11.06a' and 'torture.2020.11.06a' into HEAD
This doesn't look very satisfying, given it's the merge commit. :-/
Quoted 8 lines
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So each individual branch is just fine, but the merge of them is not. Fun.
These have been passing quite a bit of rcutorture over here, including preemptible kernels running !SMP, but admittedly on x86 rather than ARMv8.
Note that this is ARMv8 on QEMU on an x86 host i.e. emulated. And it's really slow as a result. Together with a bunch of debug tools including lockdep.
Then I don't envy you the bisection process! ;-)
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One approach would be to binary-search the combinations of merges. Except that there are six of them, so there are 64 combinations, of which you have tested only 8 thus far (none, one each, and all).
But are you sure that the bisection points labeled "good" really are good? For example, what is the distribution of first failure times in the points labeled "bad" vs. the runtime used to make a "good" determination? Alternatively, just try a longer run on each of the commits feeding into the merge point.
Quoted 6 lines
Yeah, I'm having doubts, and this might be even more non-deterministic that I thought and some 'good' could maybe be 'bad' if I had re-run them? I don't know. One thing I can try is to make sure I run it more than once, but I'm definitely not doing that manually, so let me try and script something so I don't have to hand-hold the bisection overnight. :-)
I know that feeling. A similar experience motivated me to upgrade my tooling, with more upgrades in the queue.

[.....]

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| [ 841.143527] arch_local_irq_restore+0x4/0x8
So we are just now restoring interrupts, hence our getting the interrupt at this point..
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| [ 841.147612] trace_preempt_on+0xf4/0x190
From within the trace code, which is apparently recording the fact that preemption is being enabled.
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| [  841.151656]  preempt_schedule_common+0x12c/0x1b0
| [  841.155869]  preempt_schedule.part.88+0x20/0x28
| [  841.160036]  preempt_schedule+0x20/0x28
I was not aware that releasing a raw spinlock could result in a direct call to preempt_schedule().
Quoted 6 lines
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| [  841.164051]  _raw_spin_unlock_irq+0x80/0x90
| [  841.168139]  rcu_gp_kthread+0xe5c/0x19a8
So the RCU grace-period kthread has spent many seconds attempting to release a lock? Am I reading this correctly? Mark Rutland, am I missing something here?
And yes, this is the RCU grace-period kthread releasing a lock.
I have no idea why that would take so long. It is acting like a self-deadlock or similar hang, except that in that case, lockdep should have complained before the RCU CPU stall warning rather than after.

Quoted 6 lines

The only thing I can suggest is sprinkling lockdep_assert_irqs_disabled() calls hither and yon. All of the code that lockdep is complaining about runs in the context of the scheduling-clock interrupt, so interrupts had jolly well be disabled! ;-)
Rerunning some of the allegedly good bisects might be more productive.

Oof, so I reran bisection, and this time confirming 3x each good run. This is what I get:

| git bisect start
| # bad: [c07b306d7fa5680777e2132662d2e6c19fb53579] kfence: Avoid stalling work queue task without allocations
| git bisect bad c07b306d7fa5680777e2132662d2e6c19fb53579
| # good: [3cea11cd5e3b00d91caf0b4730194039b45c5891] Linux 5.10-rc2
| git bisect good 27598e7e73260ed0b2917eb02d4a515ebb578313
| # good: [3e5acbea719e66ef3be64fe74c99cc905ca697dc] Merge remote-tracking branch 'wireless-drivers-next/master' into master
| git bisect good 3e5acbea719e66ef3be64fe74c99cc905ca697dc
| # good: [491a5a9a2fea28353d99621b8abb83b6928b4e36] Merge remote-tracking branch 'sound-asoc/for-next' into master
| git bisect good 491a5a9a2fea28353d99621b8abb83b6928b4e36
| # bad: [502f8643d6e21c7e370a0b75131130cc51609055] Merge remote-tracking branch 'phy-next/next' into master
| git bisect bad 502f8643d6e21c7e370a0b75131130cc51609055
| # good: [6693cb1fa5ea7b91ec00f9404776a095713face5] Merge remote-tracking branch 'tip/auto-latest' into master
| git bisect good 6693cb1fa5ea7b91ec00f9404776a095713face5
| # good: [b790e3afead9357195b6d1e1b6cd9b3521503ad2] Merge branch 'tglx-pc.2020.10.30a' into HEAD
| git bisect good b790e3afead9357195b6d1e1b6cd9b3521503ad2
| # bad: [7bd5bb161657717d576798f62b0e8d5b44653139] Merge remote-tracking branch 'drivers-x86/for-next' into master
| git bisect bad 7bd5bb161657717d576798f62b0e8d5b44653139
| # bad: [e71eb4c4d42bcf36a3a7ede30fd320d47b3c8cb8] Merge remote-tracking branch 'xen-tip/linux-next' into master
| git bisect bad e71eb4c4d42bcf36a3a7ede30fd320d47b3c8cb8
| # bad: [c0a41bf9dbc751692c8cb1a44bfd48e70e8bef7f] docs: Remove redundant "``" from Requirements.rst
| git bisect bad c0a41bf9dbc751692c8cb1a44bfd48e70e8bef7f
| # bad: [c293fb8f7de6c2fce11cb01a0218d668df326bcd] torture: Make --kcsan specify lockdep
| git bisect bad c293fb8f7de6c2fce11cb01a0218d668df326bcd
| # good: [5068ab7dcb6a526a401054ebe0d416f979efb3e1] rcutorture: Add testing for RCU's global memory ordering
| git bisect good 5068ab7dcb6a526a401054ebe0d416f979efb3e1
| # good: [bea68a13bbbdc575a2c868dabd7b454c2eddc618] rcu/segcblist: Add additional comments to explain smp_mb()
| git bisect good bea68a13bbbdc575a2c868dabd7b454c2eddc618
| # first bad commit: [c293fb8f7de6c2fce11cb01a0218d668df326bcd] torture: Make --kcsan specify lockdep

Which clearly is ridiculous! So my guess is this probably had existed before, but something in -next is making it more visible.

Short of giving up, I can try your suggestion of sprinkling lockdep_assert_irqs_disabled() everywhere, or if you have a patch to apply that would give some other debug output you wanted I can run that too.

Thanks,
-- Marco

Paul E. McKenney

maintainer

2020-11-13 17:20 UTC #18 lore raw

Quoted 175 lines · Marco Elver

Quoted 102 lines · Paul E. McKenney
Quoted 71 lines · Marco Elver
Quoted 70 lines · Paul E. McKenney
Quoted 23 lines · Marco Elver
Quoted 1 line · Marco Elver
On Thu, 12 Nov 2020 at 01:11, Paul E. McKenney <[email protected]> wrote:
[...]
Quoted 7 lines
Quoted 4 lines
Quoted 2 lines
This assert didn't fire yet, I just get more of the below. I'll keep rerunning, but am not too hopeful...
Is bisection a possibility?
I've been running a bisection for past ~12h, and am making slow progress. It might be another 12h, but I think it'll get there.
Bisection gave me this:
| git bisect start
| # bad: [c07b306d7fa5680777e2132662d2e6c19fb53579] kfence: Avoid stalling work queue task without allocations
| git bisect bad c07b306d7fa5680777e2132662d2e6c19fb53579
| # good: [3cea11cd5e3b00d91caf0b4730194039b45c5891] Linux 5.10-rc2
| git bisect good 27598e7e73260ed0b2917eb02d4a515ebb578313
| # good: [3e5acbea719e66ef3be64fe74c99cc905ca697dc] Merge remote-tracking branch 'wireless-drivers-next/master' into master
| git bisect good 3e5acbea719e66ef3be64fe74c99cc905ca697dc
| # good: [491a5a9a2fea28353d99621b8abb83b6928b4e36] Merge remote-tracking branch 'sound-asoc/for-next' into master
| git bisect good 491a5a9a2fea28353d99621b8abb83b6928b4e36
| # bad: [502f8643d6e21c7e370a0b75131130cc51609055] Merge remote-tracking branch 'phy-next/next' into master
Quoted 8 lines
| git bisect bad 502f8643d6e21c7e370a0b75131130cc51609055
| # good: [6693cb1fa5ea7b91ec00f9404776a095713face5] Merge remote-tracking branch 'tip/auto-latest' into master
| git bisect good 6693cb1fa5ea7b91ec00f9404776a095713face5
| # bad: [b790e3afead9357195b6d1e1b6cd9b3521503ad2] Merge branch 'tglx-pc.2020.10.30a' into HEAD
| git bisect bad b790e3afead9357195b6d1e1b6cd9b3521503ad2
| # bad: [765b512bb3d639bfad7dd43c288ee085236c7267] Merge branches 'cpuinfo.2020.11.06a', 'doc.2020.11.06a', 'fixes.2020.11.02a', 'lockdep.2020.11.02a', 'tasks.2020.11.06a' and 'torture.2020.11.06a' into HEAD
| git bisect bad 765b512bb3d639bfad7dd43c288ee085236c7267
| # good: [01f9e708d9eae6335ae9ff25ab09893c20727a55] tools/rcutorture: Fix BUG parsing of console.log
So torture.2020.11.06a is OK.
Quoted 2 lines
| git bisect good 01f9e708d9eae6335ae9ff25ab09893c20727a55
| # good: [1be6ab91e2db157faedb7f16ab0636a80745a073] srcu: Take early exit on memory-allocation failure
As is fixes.2020.11.02a.
Quoted 2 lines
| git bisect good 1be6ab91e2db157faedb7f16ab0636a80745a073
| # good: [65e9eb1ccfe56b41a0d8bfec651ea014968413cb] rcu: Prevent RCU_LOCKDEP_WARN() from swallowing the condition
And lockdep.2020.11.02a.
Quoted 2 lines
| git bisect good 65e9eb1ccfe56b41a0d8bfec651ea014968413cb
| # good: [c386e29d43728778ddd642fa73cc582bee684171] docs/rcu: Update the call_rcu() API
And doc.2020.11.06a.
Quoted 2 lines
| git bisect good c386e29d43728778ddd642fa73cc582bee684171
| # good: [27c0f1448389baf7f309b69e62d4b531c9395e88] rcutorture: Make grace-period kthread report match RCU flavor being tested
And the first three commits of tasks.2020.11.06a.
Quoted 2 lines
| git bisect good 27c0f1448389baf7f309b69e62d4b531c9395e88
| # good: [3fcd6a230fa7d03bffcb831a81b40435c146c12b] x86/cpu: Avoid cpuinfo-induced IPIing of idle CPUs
And cpuinfo.2020.11.06a.
Quoted 2 lines
| git bisect good 3fcd6a230fa7d03bffcb831a81b40435c146c12b
| # good: [75dc2da5ecd65bdcbfc4d59b9d9b7342c61fe374] rcu-tasks: Make the units of ->init_fract be jiffies
And the remaining commit of tasks.2020.11.06a.
Quoted 4 lines
| git bisect good 75dc2da5ecd65bdcbfc4d59b9d9b7342c61fe374
| # first bad commit: [765b512bb3d639bfad7dd43c288ee085236c7267] Merge branches 'cpuinfo.2020.11.06a', 'doc.2020.11.06a', 'fixes.2020.11.02a', 'lockdep.2020.11.02a', 'tasks.2020.11.06a' and 'torture.2020.11.06a' into HEAD
This doesn't look very satisfying, given it's the merge commit. :-/
Quoted 8 lines
Quoted 4 lines
So each individual branch is just fine, but the merge of them is not. Fun.
These have been passing quite a bit of rcutorture over here, including preemptible kernels running !SMP, but admittedly on x86 rather than ARMv8.
Note that this is ARMv8 on QEMU on an x86 host i.e. emulated. And it's really slow as a result. Together with a bunch of debug tools including lockdep.
Then I don't envy you the bisection process! ;-)
Quoted 10 lines
Quoted 9 lines
One approach would be to binary-search the combinations of merges. Except that there are six of them, so there are 64 combinations, of which you have tested only 8 thus far (none, one each, and all).
But are you sure that the bisection points labeled "good" really are good? For example, what is the distribution of first failure times in the points labeled "bad" vs. the runtime used to make a "good" determination? Alternatively, just try a longer run on each of the commits feeding into the merge point.
Quoted 6 lines
Yeah, I'm having doubts, and this might be even more non-deterministic that I thought and some 'good' could maybe be 'bad' if I had re-run them? I don't know. One thing I can try is to make sure I run it more than once, but I'm definitely not doing that manually, so let me try and script something so I don't have to hand-hold the bisection overnight. :-)
I know that feeling. A similar experience motivated me to upgrade my tooling, with more upgrades in the queue.
[.....]
Quoted 30 lines
Quoted 17 lines
Quoted 17 lines
Quoted 1 line
| [ 841.143527] arch_local_irq_restore+0x4/0x8
So we are just now restoring interrupts, hence our getting the interrupt at this point..
Quoted 1 line
| [ 841.147612] trace_preempt_on+0xf4/0x190
From within the trace code, which is apparently recording the fact that preemption is being enabled.
Quoted 3 lines
| [  841.151656]  preempt_schedule_common+0x12c/0x1b0
| [  841.155869]  preempt_schedule.part.88+0x20/0x28
| [  841.160036]  preempt_schedule+0x20/0x28
I was not aware that releasing a raw spinlock could result in a direct call to preempt_schedule().
Quoted 6 lines
Quoted 6 lines
Quoted 2 lines
| [  841.164051]  _raw_spin_unlock_irq+0x80/0x90
| [  841.168139]  rcu_gp_kthread+0xe5c/0x19a8
So the RCU grace-period kthread has spent many seconds attempting to release a lock? Am I reading this correctly? Mark Rutland, am I missing something here?
And yes, this is the RCU grace-period kthread releasing a lock.
I have no idea why that would take so long. It is acting like a self-deadlock or similar hang, except that in that case, lockdep should have complained before the RCU CPU stall warning rather than after.
Quoted 6 lines
The only thing I can suggest is sprinkling lockdep_assert_irqs_disabled() calls hither and yon. All of the code that lockdep is complaining about runs in the context of the scheduling-clock interrupt, so interrupts had jolly well be disabled! ;-)
Rerunning some of the allegedly good bisects might be more productive.
Oof, so I reran bisection, and this time confirming 3x each good run. This is what I get:
| git bisect start
| # bad: [c07b306d7fa5680777e2132662d2e6c19fb53579] kfence: Avoid stalling work queue task without allocations
| git bisect bad c07b306d7fa5680777e2132662d2e6c19fb53579
| # good: [3cea11cd5e3b00d91caf0b4730194039b45c5891] Linux 5.10-rc2
| git bisect good 27598e7e73260ed0b2917eb02d4a515ebb578313
| # good: [3e5acbea719e66ef3be64fe74c99cc905ca697dc] Merge remote-tracking branch 'wireless-drivers-next/master' into master
| git bisect good 3e5acbea719e66ef3be64fe74c99cc905ca697dc
| # good: [491a5a9a2fea28353d99621b8abb83b6928b4e36] Merge remote-tracking branch 'sound-asoc/for-next' into master
| git bisect good 491a5a9a2fea28353d99621b8abb83b6928b4e36
| # bad: [502f8643d6e21c7e370a0b75131130cc51609055] Merge remote-tracking branch 'phy-next/next' into master
| git bisect bad 502f8643d6e21c7e370a0b75131130cc51609055
| # good: [6693cb1fa5ea7b91ec00f9404776a095713face5] Merge remote-tracking branch 'tip/auto-latest' into master
| git bisect good 6693cb1fa5ea7b91ec00f9404776a095713face5
| # good: [b790e3afead9357195b6d1e1b6cd9b3521503ad2] Merge branch 'tglx-pc.2020.10.30a' into HEAD
| git bisect good b790e3afead9357195b6d1e1b6cd9b3521503ad2
| # bad: [7bd5bb161657717d576798f62b0e8d5b44653139] Merge remote-tracking branch 'drivers-x86/for-next' into master
| git bisect bad 7bd5bb161657717d576798f62b0e8d5b44653139
| # bad: [e71eb4c4d42bcf36a3a7ede30fd320d47b3c8cb8] Merge remote-tracking branch 'xen-tip/linux-next' into master
| git bisect bad e71eb4c4d42bcf36a3a7ede30fd320d47b3c8cb8
| # bad: [c0a41bf9dbc751692c8cb1a44bfd48e70e8bef7f] docs: Remove redundant "``" from Requirements.rst
| git bisect bad c0a41bf9dbc751692c8cb1a44bfd48e70e8bef7f
| # bad: [c293fb8f7de6c2fce11cb01a0218d668df326bcd] torture: Make --kcsan specify lockdep
| git bisect bad c293fb8f7de6c2fce11cb01a0218d668df326bcd
| # good: [5068ab7dcb6a526a401054ebe0d416f979efb3e1] rcutorture: Add testing for RCU's global memory ordering
| git bisect good 5068ab7dcb6a526a401054ebe0d416f979efb3e1
| # good: [bea68a13bbbdc575a2c868dabd7b454c2eddc618] rcu/segcblist: Add additional comments to explain smp_mb()
| git bisect good bea68a13bbbdc575a2c868dabd7b454c2eddc618
| # first bad commit: [c293fb8f7de6c2fce11cb01a0218d668df326bcd] torture: Make --kcsan specify lockdep

Quoted 7 lines

Which clearly is ridiculous! So my guess is this probably had existed before, but something in -next is making it more visible.
Short of giving up, I can try your suggestion of sprinkling lockdep_assert_irqs_disabled() everywhere, or if you have a patch to apply that would give some other debug output you wanted I can run that too.

I don't have a patch, but if you are still seeing lots of workqueue lockups before the RCU CPU stall warning, I again suggest adding the backtrace as called out in my earlier email. The idea here is to see what is causing these lockups.

I can send a formal patch for this if you wish, but today is crazy, so I cannot promise it before this evening, Pacific Time.

Thanx, Paul

Paul E. McKenney

maintainer

2020-11-13 17:57 UTC #19 lore raw

In reply to Paul E. McKenney

Quoted 1 line · Paul E. McKenney

On Thu, Nov 12, 2020 at 05:14:39PM +0100, Marco Elver wrote:

[ . . . ]

Quoted 8 lines

Quoted 1 line
| [ 334.160218] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 15s!
It might be instructive to cause this code to provoke a backtrace. I suggest adding something like "trigger_single_cpu_backtrace(cpu)" in kernel/workqueue.c's function named wq_watchdog_timer_fn() somewhere within its "if" statement that is preceded with the "did we stall?" comment. Or just search for "BUG: workqueue lockup - pool" within kernel/workqueue.c.

And I did get a small but unexpected gift of time, so here is an (untested) patch.

Thanx, Paul

------------------------------------------------------------------------

kernel/workqueue.c +1 -0

index 437935e..f3d4ff7 100644
@@ -5792,6 +5792,7 @@ static void wq_watchdog_timer_fn(struct timer_list *unused)
 			pr_cont_pool_info(pool);
 			pr_cont(" stuck for %us!\n",
 				jiffies_to_msecs(jiffies - pool_ts) / 1000);
+			trigger_single_cpu_backtrace(cpu);
 		}
 	}

Marco Elver

author maintainer

2020-11-17 10:52 UTC #20 lore raw

Quoted 26 lines · Paul E. McKenney

Quoted 1 line · Paul E. McKenney
On Thu, Nov 12, 2020 at 05:14:39PM +0100, Marco Elver wrote:
[ . . . ]
Quoted 8 lines
Quoted 1 line
| [ 334.160218] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 15s!
It might be instructive to cause this code to provoke a backtrace. I suggest adding something like "trigger_single_cpu_backtrace(cpu)" in kernel/workqueue.c's function named wq_watchdog_timer_fn() somewhere within its "if" statement that is preceded with the "did we stall?" comment. Or just search for "BUG: workqueue lockup - pool" within kernel/workqueue.c.
And I did get a small but unexpected gift of time, so here is an (untested) patch.
Thanx, Paul
------------------------------------------------------------------------
kernel/workqueue.c +0 -0
index 437935e..f3d4ff7 100644

kernel/workqueue.c static void wq_watchdog_timer_fn(struct timer_list *unused) · line 5798

Quoted 7 lines

kernel/workqueue.c +1 -0

@@ -5792,6 +5792,7 @@ static void wq_watchdog_timer_fn(struct timer_list *unused)
 			pr_cont_pool_info(pool);
 			pr_cont(" stuck for %us!\n",
 				jiffies_to_msecs(jiffies - pool_ts) / 1000);
+			trigger_single_cpu_backtrace(cpu);
 		}
 	}

That didn't quite work, although the system this is running on only has 1 CPU, so dump_stack() should give us the information we want (see below). Not sure if that helps though.

Thanks,
-- Marco

------ >8 ------

| Testing all events: OK
| Running tests again, along with the function tracer
| Running tests on all trace events:
| Testing all events: 
| hrtimer: interrupt took 10322624 ns
| BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 19s!
| CPU: 0 PID: 26 Comm: kcompactd0 Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #2
| Hardware name: linux,dummy-virt (DT)
| Call trace:
|  dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
|  show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
|  __dump_stack lib/dump_stack.c:77 [inline]
|  dump_stack+0x140/0x1bc lib/dump_stack.c:118
|  wq_watchdog_timer_fn+0x338/0x340 kernel/workqueue.c:5796
|  call_timer_fn+0xe8/0x480 kernel/time/timer.c:1410
|  expire_timers kernel/time/timer.c:1455 [inline]
|  __run_timers.part.0+0x2e8/0x470 kernel/time/timer.c:1747
|  __run_timers kernel/time/timer.c:1728 [inline]
|  run_timer_softirq+0x90/0xa8 kernel/time/timer.c:1762
|  __do_softirq+0x188/0x6b4 kernel/softirq.c:298
|  do_softirq_own_stack include/linux/interrupt.h:568 [inline]
|  invoke_softirq kernel/softirq.c:393 [inline]
|  __irq_exit_rcu kernel/softirq.c:423 [inline]
|  irq_exit+0x1cc/0x1e0 kernel/softirq.c:447
|  __handle_domain_irq+0xb4/0x130 kernel/irq/irqdesc.c:690
|  handle_domain_irq include/linux/irqdesc.h:170 [inline]
|  gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
|  el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
|  arch_local_irq_restore arch/arm64/include/asm/irqflags.h:124 [inline]
|  rcu_irq_exit_irqson+0x40/0x78 kernel/rcu/tree.c:832
|  trace_preempt_enable_rcuidle include/trace/events/preemptirq.h:55 [inline]
|  trace_preempt_on+0x144/0x1a0 kernel/trace/trace_preemptirq.c:123
|  preempt_latency_stop kernel/sched/core.c:4197 [inline]
|  preempt_latency_stop kernel/sched/core.c:4194 [inline]
|  preempt_schedule_common+0xf8/0x1a8 kernel/sched/core.c:4682
|  preempt_schedule+0x38/0x40 kernel/sched/core.c:4706
|  __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
|  _raw_spin_unlock_irqrestore+0x90/0xa0 kernel/locking/spinlock.c:191
|  spin_unlock_irqrestore include/linux/spinlock.h:409 [inline]
|  finish_wait+0x78/0xa0 kernel/sched/wait.c:382
|  kcompactd+0x3a0/0x4b8 mm/compaction.c:2817
|  kthread+0x13c/0x188 kernel/kthread.c:292
|  ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
| Showing busy workqueues and worker pools:
| workqueue events: flags=0x0
|   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
|     pending: vmstat_shepherd
| workqueue events_power_efficient: flags=0x82
|   pwq 2: cpus=0 flags=0x4 nice=0 active=3/256 refcnt=5
|     in-flight: 7:check_lifetime
|     pending: do_cache_clean, neigh_periodic_work
| pool 2: cpus=0 flags=0x4 nice=0 hung=19s workers=2 idle: 61
| rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
| 	(detected by 0, t=3752 jiffies, g=2501, q=1)
| rcu: All QSes seen, last rcu_preempt kthread activity 2981 (4295017301-4295014320), jiffies_till_next_fqs=1, root ->qsmask 0x0
| rcu: rcu_preempt kthread starved for 2981 jiffies! g2501 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
| rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
| rcu: RCU grace-period kthread stack dump:
| task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
| Call trace:
|  __switch_to+0x10c/0x200 arch/arm64/kernel/process.c:578
|  context_switch kernel/sched/core.c:3773 [inline]
|  __schedule+0x2d8/0x980 kernel/sched/core.c:4522
|  preempt_schedule_notrace+0x70/0x1c0 kernel/sched/core.c:4754
|  __ftrace_ops_list_func kernel/trace/ftrace.c:6956 [inline]
|  ftrace_ops_list_func+0x108/0x230 kernel/trace/ftrace.c:6977
|  ftrace_graph_call+0x0/0x4
|  preempt_count_add+0x8/0x1a0 arch/arm64/include/asm/atomic.h:65
|  schedule+0x44/0x100 kernel/sched/core.c:4599
|  schedule_timeout+0x240/0x538 kernel/time/timer.c:1871
|  rcu_gp_fqs_loop kernel/rcu/tree.c:1942 [inline]
|  rcu_gp_kthread+0x618/0x1bd8 kernel/rcu/tree.c:2115
|  kthread+0x13c/0x188 kernel/kthread.c:292
|  ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
| 
| ================================
| WARNING: inconsistent lock state
| 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #2 Not tainted
| --------------------------------
| inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
| event_benchmark/105 [HC0[0]:SC0[0]:HE0:SE1] takes:
| ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline]
| ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
| ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline]
| ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581
| {IN-HARDIRQ-W} state was registered at:
|   mark_lock kernel/locking/lockdep.c:4374 [inline]
|   mark_usage kernel/locking/lockdep.c:4302 [inline]
|   __lock_acquire+0xab8/0x1a50 kernel/locking/lockdep.c:4785
|   lock_acquire kernel/locking/lockdep.c:5436 [inline]
|   lock_acquire+0x268/0x508 kernel/locking/lockdep.c:5401
|   __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
|   _raw_spin_lock_irqsave+0x78/0x14c kernel/locking/spinlock.c:159
|   print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline]
|   check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
|   rcu_pending kernel/rcu/tree.c:3752 [inline]
|   rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581
|   update_process_times+0x6c/0xb8 kernel/time/timer.c:1709
|   tick_sched_handle.isra.0+0x58/0x88 kernel/time/tick-sched.c:176
|   tick_sched_timer+0x68/0xe0 kernel/time/tick-sched.c:1328
|   __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
|   __hrtimer_run_queues+0x288/0x730 kernel/time/hrtimer.c:1583
|   hrtimer_interrupt+0x114/0x288 kernel/time/hrtimer.c:1645
|   timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline]
|   arch_timer_handler_virt+0x50/0x70 drivers/clocksource/arm_arch_timer.c:658
|   handle_percpu_devid_irq+0x104/0x4c0 kernel/irq/chip.c:930
|   generic_handle_irq_desc include/linux/irqdesc.h:152 [inline]
|   generic_handle_irq+0x54/0x78 kernel/irq/irqdesc.c:650
|   __handle_domain_irq+0xac/0x130 kernel/irq/irqdesc.c:687
|   handle_domain_irq include/linux/irqdesc.h:170 [inline]
|   gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
|   el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
|   arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline]
|   preempt_schedule_irq+0x44/0xa0 kernel/sched/core.c:4782
|   arm64_preempt_schedule_irq+0xd0/0x118 arch/arm64/kernel/process.c:726
|   el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:664
|   arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline]
|   trace_do_benchmark kernel/trace/trace_benchmark.c:56 [inline]
|   benchmark_event_kthread+0x144/0x4b0 kernel/trace/trace_benchmark.c:154
|   kthread+0x13c/0x188 kernel/kthread.c:292
|   ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
| irq event stamp: 12978
| hardirqs last  enabled at (12977): [<ffffbb6e0a62ea50>] preempt_schedule_irq+0x40/0xa0 kernel/sched/core.c:4782
| hardirqs last disabled at (12978): [<ffffbb6e092123c0>] el1_irq+0x80/0x180 arch/arm64/kernel/entry.S:648
| softirqs last  enabled at (8540): [<ffffbb6e09210b80>] __do_softirq+0x630/0x6b4 kernel/softirq.c:325
| softirqs last disabled at (8531): [<ffffbb6e092c6c54>] do_softirq_own_stack include/linux/interrupt.h:568 [inline]
| softirqs last disabled at (8531): [<ffffbb6e092c6c54>] invoke_softirq kernel/softirq.c:393 [inline]
| softirqs last disabled at (8531): [<ffffbb6e092c6c54>] __irq_exit_rcu kernel/softirq.c:423 [inline]
| softirqs last disabled at (8531): [<ffffbb6e092c6c54>] irq_exit+0x1cc/0x1e0 kernel/softirq.c:447
| 
| other info that might help us debug this:
|  Possible unsafe locking scenario:
| 
|        CPU0
|        ----
|   lock(rcu_node_0);
|   <Interrupt>
|     lock(rcu_node_0);
| 
|  *** DEADLOCK ***
| 
| 1 lock held by event_benchmark/105:
|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline]
|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline]
|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581
| 
| stack backtrace:
| CPU: 0 PID: 105 Comm: event_benchmark Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #2
| Hardware name: linux,dummy-virt (DT)
| Call trace:
|  dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
|  show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
|  __dump_stack lib/dump_stack.c:77 [inline]
|  dump_stack+0x140/0x1bc lib/dump_stack.c:118
|  print_usage_bug kernel/locking/lockdep.c:3739 [inline]
|  print_usage_bug+0x2a0/0x2f0 kernel/locking/lockdep.c:3706
|  valid_state kernel/locking/lockdep.c:3750 [inline]
|  mark_lock_irq kernel/locking/lockdep.c:3953 [inline]
|  mark_lock.part.0+0x438/0x4e8 kernel/locking/lockdep.c:4410
|  mark_lock kernel/locking/lockdep.c:4008 [inline]
|  mark_held_locks+0x54/0x90 kernel/locking/lockdep.c:4011
|  __trace_hardirqs_on_caller kernel/locking/lockdep.c:4029 [inline]
|  lockdep_hardirqs_on_prepare+0xe0/0x290 kernel/locking/lockdep.c:4097
|  trace_hardirqs_on+0x90/0x370 kernel/trace/trace_preemptirq.c:49
|  el1_irq+0xdc/0x180 arch/arm64/kernel/entry.S:685
|  arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline]
|  preempt_schedule_irq+0x44/0xa0 kernel/sched/core.c:4782
|  arm64_preempt_schedule_irq+0xd0/0x118 arch/arm64/kernel/process.c:726
|  el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:664
|  arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline]
|  trace_do_benchmark kernel/trace/trace_benchmark.c:56 [inline]
|  benchmark_event_kthread+0x144/0x4b0 kernel/trace/trace_benchmark.c:154
|  kthread+0x13c/0x188 kernel/kthread.c:292
|  ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
| BUG: scheduling while atomic: event_benchmark/105/0x00000002
| INFO: lockdep is turned off.
| Modules linked in:
| Preemption disabled at:
| [<ffffbb6e0a62ea4c>] preempt_schedule_irq+0x3c/0xa0 kernel/sched/core.c:4781
| CPU: 0 PID: 105 Comm: event_benchmark Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #2
| Hardware name: linux,dummy-virt (DT)
| Call trace:
|  dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
|  show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
|  __dump_stack lib/dump_stack.c:77 [inline]
|  dump_stack+0x140/0x1bc lib/dump_stack.c:118
|  __schedule_bug+0xcc/0xe0 kernel/sched/core.c:4262
|  schedule_debug kernel/sched/core.c:4289 [inline]
|  __schedule+0x878/0x980 kernel/sched/core.c:4417
|  preempt_schedule_irq+0x4c/0xa0 kernel/sched/core.c:4783
|  arm64_preempt_schedule_irq+0xd0/0x118 arch/arm64/kernel/process.c:726
|  el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:664
|  arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline]
|  trace_do_benchmark kernel/trace/trace_benchmark.c:56 [inline]
|  benchmark_event_kthread+0x144/0x4b0 kernel/trace/trace_benchmark.c:154
|  kthread+0x13c/0x188 kernel/kthread.c:292
|  ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961

Paul E. McKenney

maintainer

2020-11-17 18:29 UTC #21 lore raw

Quoted 22 lines · Marco Elver

Quoted 21 lines · Paul E. McKenney
Quoted 1 line · Paul E. McKenney
On Thu, Nov 12, 2020 at 05:14:39PM +0100, Marco Elver wrote:
[ . . . ]
Quoted 8 lines
Quoted 1 line
| [ 334.160218] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 15s!
It might be instructive to cause this code to provoke a backtrace. I suggest adding something like "trigger_single_cpu_backtrace(cpu)" in kernel/workqueue.c's function named wq_watchdog_timer_fn() somewhere within its "if" statement that is preceded with the "did we stall?" comment. Or just search for "BUG: workqueue lockup - pool" within kernel/workqueue.c.
And I did get a small but unexpected gift of time, so here is an (untested) patch.
Thanx, Paul
------------------------------------------------------------------------

Quoted 16 lines

kernel/workqueue.c static void wq_watchdog_timer_fn(struct timer_list *unused) · line 5798
Quoted 12 lines
kernel/workqueue.c +1 -0
index 437935e..f3d4ff7 100644
@@ -5792,6 +5792,7 @@ static void wq_watchdog_timer_fn(struct timer_list *unused)
 			pr_cont_pool_info(pool);
 			pr_cont(" stuck for %us!\n",
 				jiffies_to_msecs(jiffies - pool_ts) / 1000);
+			trigger_single_cpu_backtrace(cpu);
 		}
 	}
 
That didn't quite work, although the system this is running on only has 1 CPU, so dump_stack() should give us the information we want (see below). Not sure if that helps though.

In that case, whatever was blocking things should be on the stack on the one hand, or we should have just now returned from an interrupt on the other. Hoping for the former...

Quoted 5 lines

Thanks,
-- Marco
------ >8 ------

Quoted 15 lines

| Testing all events: OK
| Running tests again, along with the function tracer
| Running tests on all trace events:
| Testing all events: 
| hrtimer: interrupt took 10322624 ns
| BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 19s!
| CPU: 0 PID: 26 Comm: kcompactd0 Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #2
| Hardware name: linux,dummy-virt (DT)
| Call trace:
|  dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
|  show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
|  __dump_stack lib/dump_stack.c:77 [inline]
|  dump_stack+0x140/0x1bc lib/dump_stack.c:118
|  wq_watchdog_timer_fn+0x338/0x340 kernel/workqueue.c:5796
|  call_timer_fn+0xe8/0x480 kernel/time/timer.c:1410

Up to here is definitely just reporting the lockup.

Quoted 7 lines

|  expire_timers kernel/time/timer.c:1455 [inline]
|  __run_timers.part.0+0x2e8/0x470 kernel/time/timer.c:1747
|  __run_timers kernel/time/timer.c:1728 [inline]
|  run_timer_softirq+0x90/0xa8 kernel/time/timer.c:1762
|  __do_softirq+0x188/0x6b4 kernel/softirq.c:298
|  do_softirq_own_stack include/linux/interrupt.h:568 [inline]
|  invoke_softirq kernel/softirq.c:393 [inline]

Up to here -might- be just reporting the lockup, or we might have had a very long timeout handler. I am not seeing any convenient trace events to check this.

Quoted 10 lines

|  __irq_exit_rcu kernel/softirq.c:423 [inline]
|  irq_exit+0x1cc/0x1e0 kernel/softirq.c:447
|  __handle_domain_irq+0xb4/0x130 kernel/irq/irqdesc.c:690
|  handle_domain_irq include/linux/irqdesc.h:170 [inline]
|  gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
|  el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
|  arch_local_irq_restore arch/arm64/include/asm/irqflags.h:124 [inline]
|  rcu_irq_exit_irqson+0x40/0x78 kernel/rcu/tree.c:832
|  trace_preempt_enable_rcuidle include/trace/events/preemptirq.h:55 [inline]
|  trace_preempt_on+0x144/0x1a0 kernel/trace/trace_preemptirq.c:123

This is taking an interrupt, and perhaps some of the later stuff is also. Of course, there might have been an immediately preceding interrupt (or series of interrupts) that took too long. The 10-millisecond interrupt called out above is nowhere near long enough to make this happen.

Quoted 8 lines

|  preempt_latency_stop kernel/sched/core.c:4197 [inline]
|  preempt_latency_stop kernel/sched/core.c:4194 [inline]
|  preempt_schedule_common+0xf8/0x1a8 kernel/sched/core.c:4682
|  preempt_schedule+0x38/0x40 kernel/sched/core.c:4706
|  __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
|  _raw_spin_unlock_irqrestore+0x90/0xa0 kernel/locking/spinlock.c:191
|  spin_unlock_irqrestore include/linux/spinlock.h:409 [inline]
|  finish_wait+0x78/0xa0 kernel/sched/wait.c:382

The above is waking up in the while-loop in kcompactd(). You are (or at least were) running CONFIG_PREEMPT=y, so the lack of cond_resched() calls should not be affecting you.

But it would be good to get the kcompactd() people to look at this (not immediately seeing who they are in MAINTAINERS). Perhaps preemption is disabled somehow and I am failing to see it.

Failing that, maybe someone knows of a way to check for overly long timeout handlers.

Thanx, Paul

Quoted 159 lines

|  kcompactd+0x3a0/0x4b8 mm/compaction.c:2817
|  kthread+0x13c/0x188 kernel/kthread.c:292
|  ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
| Showing busy workqueues and worker pools:
| workqueue events: flags=0x0
|   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
|     pending: vmstat_shepherd
| workqueue events_power_efficient: flags=0x82
|   pwq 2: cpus=0 flags=0x4 nice=0 active=3/256 refcnt=5
|     in-flight: 7:check_lifetime
|     pending: do_cache_clean, neigh_periodic_work
| pool 2: cpus=0 flags=0x4 nice=0 hung=19s workers=2 idle: 61
| rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
| 	(detected by 0, t=3752 jiffies, g=2501, q=1)
| rcu: All QSes seen, last rcu_preempt kthread activity 2981 (4295017301-4295014320), jiffies_till_next_fqs=1, root ->qsmask 0x0
| rcu: rcu_preempt kthread starved for 2981 jiffies! g2501 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
| rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
| rcu: RCU grace-period kthread stack dump:
| task:rcu_preempt     state:R  running task     stack:    0 pid:   10 ppid:     2 flags:0x00000428
| Call trace:
|  __switch_to+0x10c/0x200 arch/arm64/kernel/process.c:578
|  context_switch kernel/sched/core.c:3773 [inline]
|  __schedule+0x2d8/0x980 kernel/sched/core.c:4522
|  preempt_schedule_notrace+0x70/0x1c0 kernel/sched/core.c:4754
|  __ftrace_ops_list_func kernel/trace/ftrace.c:6956 [inline]
|  ftrace_ops_list_func+0x108/0x230 kernel/trace/ftrace.c:6977
|  ftrace_graph_call+0x0/0x4
|  preempt_count_add+0x8/0x1a0 arch/arm64/include/asm/atomic.h:65
|  schedule+0x44/0x100 kernel/sched/core.c:4599
|  schedule_timeout+0x240/0x538 kernel/time/timer.c:1871
|  rcu_gp_fqs_loop kernel/rcu/tree.c:1942 [inline]
|  rcu_gp_kthread+0x618/0x1bd8 kernel/rcu/tree.c:2115
|  kthread+0x13c/0x188 kernel/kthread.c:292
|  ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
| 
| ================================
| WARNING: inconsistent lock state
| 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #2 Not tainted
| --------------------------------
| inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
| event_benchmark/105 [HC0[0]:SC0[0]:HE0:SE1] takes:
| ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline]
| ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
| ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline]
| ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581
| {IN-HARDIRQ-W} state was registered at:
|   mark_lock kernel/locking/lockdep.c:4374 [inline]
|   mark_usage kernel/locking/lockdep.c:4302 [inline]
|   __lock_acquire+0xab8/0x1a50 kernel/locking/lockdep.c:4785
|   lock_acquire kernel/locking/lockdep.c:5436 [inline]
|   lock_acquire+0x268/0x508 kernel/locking/lockdep.c:5401
|   __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
|   _raw_spin_lock_irqsave+0x78/0x14c kernel/locking/spinlock.c:159
|   print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline]
|   check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
|   rcu_pending kernel/rcu/tree.c:3752 [inline]
|   rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581
|   update_process_times+0x6c/0xb8 kernel/time/timer.c:1709
|   tick_sched_handle.isra.0+0x58/0x88 kernel/time/tick-sched.c:176
|   tick_sched_timer+0x68/0xe0 kernel/time/tick-sched.c:1328
|   __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
|   __hrtimer_run_queues+0x288/0x730 kernel/time/hrtimer.c:1583
|   hrtimer_interrupt+0x114/0x288 kernel/time/hrtimer.c:1645
|   timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline]
|   arch_timer_handler_virt+0x50/0x70 drivers/clocksource/arm_arch_timer.c:658
|   handle_percpu_devid_irq+0x104/0x4c0 kernel/irq/chip.c:930
|   generic_handle_irq_desc include/linux/irqdesc.h:152 [inline]
|   generic_handle_irq+0x54/0x78 kernel/irq/irqdesc.c:650
|   __handle_domain_irq+0xac/0x130 kernel/irq/irqdesc.c:687
|   handle_domain_irq include/linux/irqdesc.h:170 [inline]
|   gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
|   el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
|   arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline]
|   preempt_schedule_irq+0x44/0xa0 kernel/sched/core.c:4782
|   arm64_preempt_schedule_irq+0xd0/0x118 arch/arm64/kernel/process.c:726
|   el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:664
|   arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline]
|   trace_do_benchmark kernel/trace/trace_benchmark.c:56 [inline]
|   benchmark_event_kthread+0x144/0x4b0 kernel/trace/trace_benchmark.c:154
|   kthread+0x13c/0x188 kernel/kthread.c:292
|   ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
| irq event stamp: 12978
| hardirqs last  enabled at (12977): [<ffffbb6e0a62ea50>] preempt_schedule_irq+0x40/0xa0 kernel/sched/core.c:4782
| hardirqs last disabled at (12978): [<ffffbb6e092123c0>] el1_irq+0x80/0x180 arch/arm64/kernel/entry.S:648
| softirqs last  enabled at (8540): [<ffffbb6e09210b80>] __do_softirq+0x630/0x6b4 kernel/softirq.c:325
| softirqs last disabled at (8531): [<ffffbb6e092c6c54>] do_softirq_own_stack include/linux/interrupt.h:568 [inline]
| softirqs last disabled at (8531): [<ffffbb6e092c6c54>] invoke_softirq kernel/softirq.c:393 [inline]
| softirqs last disabled at (8531): [<ffffbb6e092c6c54>] __irq_exit_rcu kernel/softirq.c:423 [inline]
| softirqs last disabled at (8531): [<ffffbb6e092c6c54>] irq_exit+0x1cc/0x1e0 kernel/softirq.c:447
| 
| other info that might help us debug this:
|  Possible unsafe locking scenario:
| 
|        CPU0
|        ----
|   lock(rcu_node_0);
|   <Interrupt>
|     lock(rcu_node_0);
| 
|  *** DEADLOCK ***
| 
| 1 lock held by event_benchmark/105:
|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline]
|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline]
|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581
| 
| stack backtrace:
| CPU: 0 PID: 105 Comm: event_benchmark Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #2
| Hardware name: linux,dummy-virt (DT)
| Call trace:
|  dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
|  show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
|  __dump_stack lib/dump_stack.c:77 [inline]
|  dump_stack+0x140/0x1bc lib/dump_stack.c:118
|  print_usage_bug kernel/locking/lockdep.c:3739 [inline]
|  print_usage_bug+0x2a0/0x2f0 kernel/locking/lockdep.c:3706
|  valid_state kernel/locking/lockdep.c:3750 [inline]
|  mark_lock_irq kernel/locking/lockdep.c:3953 [inline]
|  mark_lock.part.0+0x438/0x4e8 kernel/locking/lockdep.c:4410
|  mark_lock kernel/locking/lockdep.c:4008 [inline]
|  mark_held_locks+0x54/0x90 kernel/locking/lockdep.c:4011
|  __trace_hardirqs_on_caller kernel/locking/lockdep.c:4029 [inline]
|  lockdep_hardirqs_on_prepare+0xe0/0x290 kernel/locking/lockdep.c:4097
|  trace_hardirqs_on+0x90/0x370 kernel/trace/trace_preemptirq.c:49
|  el1_irq+0xdc/0x180 arch/arm64/kernel/entry.S:685
|  arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline]
|  preempt_schedule_irq+0x44/0xa0 kernel/sched/core.c:4782
|  arm64_preempt_schedule_irq+0xd0/0x118 arch/arm64/kernel/process.c:726
|  el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:664
|  arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline]
|  trace_do_benchmark kernel/trace/trace_benchmark.c:56 [inline]
|  benchmark_event_kthread+0x144/0x4b0 kernel/trace/trace_benchmark.c:154
|  kthread+0x13c/0x188 kernel/kthread.c:292
|  ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
| BUG: scheduling while atomic: event_benchmark/105/0x00000002
| INFO: lockdep is turned off.
| Modules linked in:
| Preemption disabled at:
| [<ffffbb6e0a62ea4c>] preempt_schedule_irq+0x3c/0xa0 kernel/sched/core.c:4781
| CPU: 0 PID: 105 Comm: event_benchmark Not tainted 5.10.0-rc3-next-20201110-00001-gc07b306d7fa5-dirty #2
| Hardware name: linux,dummy-virt (DT)
| Call trace:
|  dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
|  show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
|  __dump_stack lib/dump_stack.c:77 [inline]
|  dump_stack+0x140/0x1bc lib/dump_stack.c:118
|  __schedule_bug+0xcc/0xe0 kernel/sched/core.c:4262
|  schedule_debug kernel/sched/core.c:4289 [inline]
|  __schedule+0x878/0x980 kernel/sched/core.c:4417
|  preempt_schedule_irq+0x4c/0xa0 kernel/sched/core.c:4783
|  arm64_preempt_schedule_irq+0xd0/0x118 arch/arm64/kernel/process.c:726
|  el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:664
|  arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline]
|  trace_do_benchmark kernel/trace/trace_benchmark.c:56 [inline]
|  benchmark_event_kthread+0x144/0x4b0 kernel/trace/trace_benchmark.c:154
|  kthread+0x13c/0x188 kernel/kthread.c:292
|  ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961

Marco Elver

author maintainer

2020-11-18 22:56 UTC #22 lore raw

On Tue, Nov 17, 2020 at 10:29AM -0800, Paul E. McKenney wrote:
[...]

Quoted 6 lines

But it would be good to get the kcompactd() people to look at this (not immediately seeing who they are in MAINTAINERS). Perhaps preemption is disabled somehow and I am failing to see it.
Failing that, maybe someone knows of a way to check for overly long timeout handlers.

I think I figured out one piece of the puzzle. Bisection keeps pointing me at some -rcu merge commit, which kept throwing me off. Nor did it help that reproduction is a bit flaky. However, I think there are 2 independent problems, but the manifestation of 1 problem triggers the 2nd problem:

1. problem: slowed forward progress (workqueue lockup / RCU stall reports)

2. problem: DEADLOCK which causes complete system lockup

	| ...
	|        CPU0
	|        ----
	|   lock(rcu_node_0);
	|   <Interrupt>
	|     lock(rcu_node_0);
	| 
	|  *** DEADLOCK ***
	| 
	| 1 lock held by event_benchmark/105:
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581
	| ...

Problem 2 can with reasonable confidence (5 trials) be fixed by reverting:

rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled

At which point the system always boots to user space -- albeit with a bunch of warnings still (attached). The supposed "good" version doesn't end up with all those warnings deterministically, so I couldn't say if the warnings are expected due to recent changes or not (Arm64 QEMU emulation, 1 CPU, and lots of debugging tools on).

Does any of that make sense?

Thanks,
-- Marco

Testing all events: OK
Running tests again, along with the function tracer Running tests on all trace events:
Testing all events:
hrtimer: interrupt took 10156432 ns

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=3752 jiffies, g=2785, q=6)

rcu: All QSes seen, last rcu_preempt kthread activity 3752 (4295396561-4295392809), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 3752 jiffies! g2785 f0x0 RCU_GP_ONOFF(3) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack: 0 pid: 10 ppid: 2 flags:0x00000428

Call trace:
 __switch_to+0x10c/0x200 arch/arm64/kernel/process.c:578
 context_switch kernel/sched/core.c:3773 [inline]
 __schedule+0x2d8/0x980 kernel/sched/core.c:4522
 preempt_schedule_common+0x4c/0x1a8 kernel/sched/core.c:4681
 preempt_schedule+0x38/0x40 kernel/sched/core.c:4706
 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock+0x94/0xa8 kernel/locking/spinlock.c:183
 rcu_gp_init kernel/rcu/tree.c:1820 [inline]
 rcu_gp_kthread+0x34c/0x1bd8 kernel/rcu/tree.c:2105
 kthread+0x13c/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=3752 jiffies, g=2817, q=6)

rcu: All QSes seen, last rcu_preempt kthread activity 856 (4295412565-4295411709), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 856 jiffies! g2817 f0x2 RCU_GP_CLEANUP(7) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack: 0 pid: 10 ppid: 2 flags:0x00000428

Call trace:
 __switch_to+0x10c/0x200 arch/arm64/kernel/process.c:578
 context_switch kernel/sched/core.c:3773 [inline]
 __schedule+0x2d8/0x980 kernel/sched/core.c:4522
 preempt_schedule_common+0x4c/0x1a8 kernel/sched/core.c:4681
 preempt_schedule+0x38/0x40 kernel/sched/core.c:4706
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x84/0x98 kernel/locking/spinlock.c:199
 rcu_gp_cleanup kernel/rcu/tree.c:2015 [inline]
 rcu_gp_kthread+0x1038/0x1bd8 kernel/rcu/tree.c:2119
 kthread+0x13c/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 16s!

Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd
workqueue events_power_efficient: flags=0x82
pwq 2: cpus=0 flags=0x4 nice=0 active=2/256 refcnt=4
pending: neigh_periodic_work, do_cache_clean
workqueue rcu_gp: flags=0x8
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
in-flight: 15:srcu_invoke_callbacks
pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=0s workers=3 idle: 111 5

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=3752 jiffies, g=2829, q=6)

rcu: All QSes seen, last rcu_preempt kthread activity 1522 (4295422970-4295421448), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 1522 jiffies! g2829 f0x2 RCU_GP_CLEANUP(7) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack: 0 pid: 10 ppid: 2 flags:0x00000428

Call trace:
 dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
 sched_show_task kernel/sched/core.c:6445 [inline]
 sched_show_task+0x1fc/0x228 kernel/sched/core.c:6420
 rcu_check_gp_kthread_starvation+0xc8/0xe4 kernel/rcu/tree_stall.h:452
 print_other_cpu_stall kernel/rcu/tree_stall.h:520 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:640 [inline]
 rcu_pending kernel/rcu/tree.c:3752 [inline]
 rcu_sched_clock_irq+0xb34/0xc48 kernel/rcu/tree.c:2581
 update_process_times+0x6c/0xb8 kernel/time/timer.c:1709
 tick_sched_handle.isra.0+0x58/0x88 kernel/time/tick-sched.c:176
 tick_sched_timer+0x68/0xe0 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
 __hrtimer_run_queues+0x288/0x730 kernel/time/hrtimer.c:1583
 hrtimer_interrupt+0x114/0x288 kernel/time/hrtimer.c:1645
 timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline]
 arch_timer_handler_virt+0x50/0x70 drivers/clocksource/arm_arch_timer.c:658
 handle_percpu_devid_irq+0x104/0x4c0 kernel/irq/chip.c:930
 generic_handle_irq_desc include/linux/irqdesc.h:152 [inline]
 generic_handle_irq+0x54/0x78 kernel/irq/irqdesc.c:650
 __handle_domain_irq+0xac/0x130 kernel/irq/irqdesc.c:687
 handle_domain_irq include/linux/irqdesc.h:170 [inline]
 gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
 el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
 arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline]
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline]
 _raw_spin_unlock_irq+0x50/0x98 kernel/locking/spinlock.c:199
 finish_lock_switch kernel/sched/core.c:3513 [inline]
 finish_task_switch+0xa8/0x290 kernel/sched/core.c:3613
 context_switch kernel/sched/core.c:3776 [inline]
 __schedule+0x2dc/0x980 kernel/sched/core.c:4522
 preempt_schedule_common+0x4c/0x1a8 kernel/sched/core.c:4681
 preempt_schedule+0x38/0x40 kernel/sched/core.c:4706
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x84/0x98 kernel/locking/spinlock.c:199
 rcu_gp_cleanup kernel/rcu/tree.c:2046 [inline]
 rcu_gp_kthread+0x1144/0x1bd8 kernel/rcu/tree.c:2119
 kthread+0x13c/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=3752 jiffies, g=2845, q=6)

rcu: All QSes seen, last rcu_preempt kthread activity 2796 (4295435367-4295432571), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 2796 jiffies! g2845 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack: 0 pid: 10 ppid: 2 flags:0x0000042a

Call trace:
 dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
 sched_show_task kernel/sched/core.c:6445 [inline]
 sched_show_task+0x1fc/0x228 kernel/sched/core.c:6420
 rcu_check_gp_kthread_starvation+0xc8/0xe4 kernel/rcu/tree_stall.h:452
 print_other_cpu_stall kernel/rcu/tree_stall.h:520 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:640 [inline]
 rcu_pending kernel/rcu/tree.c:3752 [inline]
 rcu_sched_clock_irq+0xb34/0xc48 kernel/rcu/tree.c:2581
 update_process_times+0x6c/0xb8 kernel/time/timer.c:1709
 tick_sched_handle.isra.0+0x58/0x88 kernel/time/tick-sched.c:176
 tick_sched_timer+0x68/0xe0 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
 __hrtimer_run_queues+0x288/0x730 kernel/time/hrtimer.c:1583
 hrtimer_interrupt+0x114/0x288 kernel/time/hrtimer.c:1645
 timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline]
 arch_timer_handler_virt+0x50/0x70 drivers/clocksource/arm_arch_timer.c:658
 handle_percpu_devid_irq+0x104/0x4c0 kernel/irq/chip.c:930
 generic_handle_irq_desc include/linux/irqdesc.h:152 [inline]
 generic_handle_irq+0x54/0x78 kernel/irq/irqdesc.c:650
 __handle_domain_irq+0xac/0x130 kernel/irq/irqdesc.c:687
 handle_domain_irq include/linux/irqdesc.h:170 [inline]
 gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
 el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:124 [inline]
 rcu_irq_enter_irqson+0x40/0x78 kernel/rcu/tree.c:1078
 trace_preempt_disable_rcuidle include/trace/events/preemptirq.h:51 [inline]
 trace_preempt_off+0x108/0x1f8 kernel/trace/trace_preemptirq.c:130
 preempt_latency_start kernel/sched/core.c:4164 [inline]
 preempt_latency_start kernel/sched/core.c:4157 [inline]
 preempt_schedule_notrace+0x170/0x1c0 kernel/sched/core.c:4747
 __ftrace_ops_list_func kernel/trace/ftrace.c:6956 [inline]
 ftrace_ops_list_func+0x108/0x230 kernel/trace/ftrace.c:6977
 ftrace_graph_call+0x0/0x4
 preempt_count_add+0x8/0x1a0 arch/arm64/include/asm/atomic.h:65
 schedule+0x44/0x100 kernel/sched/core.c:4599
 schedule_timeout+0x240/0x538 kernel/time/timer.c:1871
 rcu_gp_fqs_loop kernel/rcu/tree.c:1942 [inline]
 rcu_gp_kthread+0x618/0x1bd8 kernel/rcu/tree.c:2115
 kthread+0x13c/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961

Paul E. McKenney

maintainer

2020-11-18 23:38 UTC #23 lore raw

Quoted 39 lines · Marco Elver

On Tue, Nov 17, 2020 at 10:29AM -0800, Paul E. McKenney wrote:
[...]
Quoted 6 lines
But it would be good to get the kcompactd() people to look at this (not immediately seeing who they are in MAINTAINERS). Perhaps preemption is disabled somehow and I am failing to see it.
Failing that, maybe someone knows of a way to check for overly long timeout handlers.
I think I figured out one piece of the puzzle. Bisection keeps pointing me at some -rcu merge commit, which kept throwing me off. Nor did it help that reproduction is a bit flaky. However, I think there are 2 independent problems, but the manifestation of 1 problem triggers the 2nd problem:
1. problem: slowed forward progress (workqueue lockup / RCU stall reports)
2. problem: DEADLOCK which causes complete system lockup
	| ...
	|        CPU0
	|        ----
	|   lock(rcu_node_0);
	|   <Interrupt>
	|     lock(rcu_node_0);
	| 
	|  *** DEADLOCK ***
	| 
	| 1 lock held by event_benchmark/105:
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581
	| ...
Problem 2 can with reasonable confidence (5 trials) be fixed by reverting:
rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled

Quoted 7 lines

At which point the system always boots to user space -- albeit with a bunch of warnings still (attached). The supposed "good" version doesn't end up with all those warnings deterministically, so I couldn't say if the warnings are expected due to recent changes or not (Arm64 QEMU emulation, 1 CPU, and lots of debugging tools on).
Does any of that make sense?

Marco, it makes all too much sense! :-/

Does the patch below help?

Thanx, Paul

------------------------------------------------------------------------

commit 444ef3bbd0f243b912fdfd51f326704f8ee872bf

Author: Peter Zijlstra <[email protected]>
Date:   Sat Aug 29 10:22:24 2020 -0700

sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled

The try_invoke_on_locked_down_task() function currently requires that interrupts be enabled, but it is called with interrupts disabled from rcu_print_task_stall(), resulting in an "IRQs not enabled as expected" diagnostic. This commit therefore updates try_invoke_on_locked_down_task() to use raw_spin_lock_irqsave() instead of raw_spin_lock_irq(), thus allowing use from either context.

Link https://lore.kernel.org/lkml/[email protected]/ open here

Reported-by [email protected]

Signed-off-by Peter Zijlstra <[email protected]>

Signed-off-by Paul E. McKenney <[email protected]>

kernel/sched/core.c +4 -5

index e172f2d..09ef5cf 100644
@@ -2984,7 +2984,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
 
 /**
  * try_invoke_on_locked_down_task - Invoke a function on task in fixed state
- * @p: Process for which the function is to be invoked.
+ * @p: Process for which the function is to be invoked, can be @current.
  * @func: Function to invoke.
  * @arg: Argument to function.
  *

@@ -3002,12 +3002,11 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
  */
 bool try_invoke_on_locked_down_task(struct task_struct *p, bool (*func)(struct task_struct *t, void *arg), void *arg)
 {
-	bool ret = false;
 	struct rq_flags rf;
+	bool ret = false;
 	struct rq *rq;
 
-	lockdep_assert_irqs_enabled();
-	raw_spin_lock_irq(&p->pi_lock);
+	raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
 	if (p->on_rq) {
 		rq = __task_rq_lock(p, &rf);
 		if (task_rq(p) == rq)

@@ -3024,7 +3023,7 @@ bool try_invoke_on_locked_down_task(struct task_struct *p, bool (*func)(struct t
 				ret = func(p, arg);
 		}
 	}
-	raw_spin_unlock_irq(&p->pi_lock);
+	raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags);
 	return ret;
 }

Marco Elver

author maintainer

2020-11-19 12:54 UTC #24 lore raw

Quoted 46 lines · Paul E. McKenney

Quoted 31 lines · Marco Elver
[...]
I think I figured out one piece of the puzzle. Bisection keeps pointing me at some -rcu merge commit, which kept throwing me off. Nor did it help that reproduction is a bit flaky. However, I think there are 2 independent problems, but the manifestation of 1 problem triggers the 2nd problem:
1. problem: slowed forward progress (workqueue lockup / RCU stall reports)
2. problem: DEADLOCK which causes complete system lockup
	| ...
	|        CPU0
	|        ----
	|   lock(rcu_node_0);
	|   <Interrupt>
	|     lock(rcu_node_0);
	| 
	|  *** DEADLOCK ***
	| 
	| 1 lock held by event_benchmark/105:
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581
	| ...
Problem 2 can with reasonable confidence (5 trials) be fixed by reverting:
rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled
Quoted 7 lines
At which point the system always boots to user space -- albeit with a bunch of warnings still (attached). The supposed "good" version doesn't end up with all those warnings deterministically, so I couldn't say if the warnings are expected due to recent changes or not (Arm64 QEMU emulation, 1 CPU, and lots of debugging tools on).
Does any of that make sense?
Marco, it makes all too much sense! :-/
Does the patch below help?
Thanx, Paul

Quoted 7 lines

------------------------------------------------------------------------
commit 444ef3bbd0f243b912fdfd51f326704f8ee872bf
Author: Peter Zijlstra <[email protected]>
Date:   Sat Aug 29 10:22:24 2020 -0700
sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled

My assumption is that this is a replacement for "rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled", right?

That seems to have the same result (same test setup) as only reverting "rcu: Don't invoke..." does: still results in a bunch of workqueue lockup warnings and RCU stall warnings, but boots to user space. I attached a log. If the warnings are expected (are they?), then it looks fine to me.

(And just in case: with "rcu: Don't invoke..." and "sched/core:
Allow..." both applied I still get DEADLOCKs -- but that's probably expected.)

Thanks,
-- Marco

Testing all events: OK
hrtimer: interrupt took 17120368 ns
Running tests again, along with the function tracer Running tests on all trace events:
Testing all events:

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 12s!

Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 17s!

------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at kernel/rcu/tree_stall.h:758 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
WARNING: CPU: 0 PID: 1 at kernel/rcu/tree_stall.h:758 rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.0-rc3-next-20201110-00003-g920304642405-dirty #30
Hardware name: linux,dummy-virt (DT)
pstate: 20000085 (nzCv daIf -PAN -UAO -TCO BTYPE=--)
pc : rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
pc : rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711
lr : __xchg_mb arch/arm64/include/asm/cmpxchg.h:88 [inline]
lr : atomic_xchg include/asm-generic/atomic-instrumented.h:615 [inline]
lr : rcu_check_gp_start_stall kernel/rcu/tree_stall.h:751 [inline]
lr : rcu_check_gp_start_stall.isra.0+0x148/0x210 kernel/rcu/tree_stall.h:711

sp : ffff800010003d20
x29: ffff800010003d20 x28: ffff274ac3a10000
x27: 0000000000000000 x26: ffff274b3dbe72d8
x25: ffffbcb867722000 x24: 0000000000000000
x23: 0000000000000000 x22: ffffbcb8681d1260
x21: ffffbcb86735b000 x20: ffffbcb867404440
x19: ffffbcb867404440 x18: 0000000000000123
x17: ffffbcb865d400f0 x16: 0000000000000002
x15: 0000000000000002 x14: 0000000000000000
x13: 003d090000000000 x12: 00001e8480000000
x11: ffffbcb867958980 x10: ffff800010003cf0
x9 : ffffbcb864f4b7c8 x8 : 0000000000000080
x7 : 0000000000000026 x6 : ffffbcb86774e4c0
x5 : 0000000000000000 x4 : 00000000d4001f4b
x3 : 0000000000000000 x2 : 0000000000000000
x1 : 0000000000000001 x0 : 0000000000000000

Call trace:
 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
 rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711
 rcu_core+0x168/0x9e0 kernel/rcu/tree.c:2719
 rcu_core_si+0x18/0x28 kernel/rcu/tree.c:2737
 __do_softirq+0x188/0x6b4 kernel/softirq.c:298
 do_softirq_own_stack include/linux/interrupt.h:568 [inline]
 invoke_softirq kernel/softirq.c:393 [inline]
 __irq_exit_rcu kernel/softirq.c:423 [inline]
 irq_exit+0x1cc/0x1e0 kernel/softirq.c:447
 __handle_domain_irq+0xb4/0x130 kernel/irq/irqdesc.c:690
 handle_domain_irq include/linux/irqdesc.h:170 [inline]
 gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
 el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
 arch_local_irq_restore+0x8/0x10 arch/arm64/include/asm/irqflags.h:124
 release_probes kernel/tracepoint.c:113 [inline]
 tracepoint_remove_func kernel/tracepoint.c:315 [inline]
 tracepoint_probe_unregister+0x220/0x378 kernel/tracepoint.c:382
 trace_event_reg+0x58/0x150 kernel/trace/trace_events.c:298
 __ftrace_event_enable_disable+0x424/0x608 kernel/trace/trace_events.c:412
 ftrace_event_enable_disable kernel/trace/trace_events.c:495 [inline]
 __ftrace_set_clr_event_nolock+0x120/0x180 kernel/trace/trace_events.c:811
 __ftrace_set_clr_event+0x60/0x90 kernel/trace/trace_events.c:833
 event_trace_self_tests+0xd4/0x114 kernel/trace/trace_events.c:3661
 event_trace_self_test_with_function kernel/trace/trace_events.c:3734 [inline]
 event_trace_self_tests_init+0x88/0xa8 kernel/trace/trace_events.c:3747
 do_one_initcall+0xa4/0x500 init/main.c:1212
 do_initcall_level init/main.c:1285 [inline]
 do_initcalls init/main.c:1301 [inline]
 do_basic_setup init/main.c:1321 [inline]
 kernel_init_freeable+0x344/0x3c4 init/main.c:1521
 kernel_init+0x20/0x16c init/main.c:1410
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
irq event stamp: 3274113
hardirqs last  enabled at (3274112): [<ffffbcb864f8aee4>] rcu_core+0x974/0x9e0 kernel/rcu/tree.c:2716
hardirqs last disabled at (3274113): [<ffffbcb866233bf0>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
hardirqs last disabled at (3274113): [<ffffbcb866233bf0>] _raw_spin_lock_irqsave+0xb8/0x14c kernel/locking/spinlock.c:159
softirqs last  enabled at (3272576): [<ffffbcb864e10b80>] __do_softirq+0x630/0x6b4 kernel/softirq.c:325
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] do_softirq_own_stack include/linux/interrupt.h:568 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] invoke_softirq kernel/softirq.c:393 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] __irq_exit_rcu kernel/softirq.c:423 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] irq_exit+0x1cc/0x1e0 kernel/softirq.c:447
---[ end trace 902768efebf5a607 ]---

rcu: rcu_preempt: wait state: RCU_GP_WAIT_GPS(1) ->state: 0x0 delta ->gp_activity 4452 ->gp_req_activity 3848 ->gp_wake_time 3848 ->gp_wake_seq 2696 ->gp_seq 2696 ->gp_seq_needed 2700 ->gp_flags 0x1
rcu: rcu_node 0:0 ->gp_seq 2696 ->gp_seq_needed 2700
rcu: RCU callbacks invoked since boot: 2583
rcu_tasks: RTGS_WAIT_CBS(11) since 567120 g:1 i:0/0 k.
rcu_tasks_rude: RTGS_WAIT_CBS(11) since 567155 g:1 i:0/1 k.
rcu_tasks_trace: RTGS_INIT(0) since 4295464549 g:0 i:0/0 k. N0 h:0/0/0

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=3752 jiffies, g=2705, q=8)

rcu: All QSes seen, last rcu_preempt kthread activity 557 (4295471128-4295470571), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 557 jiffies! g2705 f0x2 RCU_GP_CLEANUP(7) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack: 0 pid: 10 ppid: 2 flags:0x00000428

Call trace:
 __switch_to+0x10c/0x200 arch/arm64/kernel/process.c:578
 context_switch kernel/sched/core.c:3772 [inline]
 __schedule+0x2d8/0x980 kernel/sched/core.c:4521
 preempt_schedule_common+0x4c/0x1a8 kernel/sched/core.c:4680
 preempt_schedule+0x38/0x40 kernel/sched/core.c:4705
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x84/0x98 kernel/locking/spinlock.c:199
 rcu_gp_cleanup kernel/rcu/tree.c:2015 [inline]
 rcu_gp_kthread+0x1038/0x1bd8 kernel/rcu/tree.c:2119
 kthread+0x13c/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961

OK
Testing ftrace filter: OK
Loading compiled-in X.509 certificates
input: gpio-keys as /devices/platform/gpio-keys/input/input0 ALSA device list:
No soundcards found.
TAP version 14
1..0
uart-pl011 9000000.pl011: no DMA platform data
EXT4-fs (sda): mounting ext3 file system using the ext4 subsystem EXT4-fs (sda): mounted filesystem with ordered data mode. Opts: (null)
VFS: Mounted root (ext3 filesystem) readonly on device 8:0.
devtmpfs: mounted
Freeing unused kernel memory: 8832K
Run /sbin/init as init process

Paul E. McKenney

maintainer

2020-11-19 15:14 UTC #25 lore raw

Quoted 49 lines · Marco Elver

Quoted 48 lines · Paul E. McKenney
Quoted 31 lines · Marco Elver
[...]
I think I figured out one piece of the puzzle. Bisection keeps pointing me at some -rcu merge commit, which kept throwing me off. Nor did it help that reproduction is a bit flaky. However, I think there are 2 independent problems, but the manifestation of 1 problem triggers the 2nd problem:
1. problem: slowed forward progress (workqueue lockup / RCU stall reports)
2. problem: DEADLOCK which causes complete system lockup
	| ...
	|        CPU0
	|        ----
	|   lock(rcu_node_0);
	|   <Interrupt>
	|     lock(rcu_node_0);
	| 
	|  *** DEADLOCK ***
	| 
	| 1 lock held by event_benchmark/105:
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581
	| ...
Problem 2 can with reasonable confidence (5 trials) be fixed by reverting:
rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled
Quoted 7 lines
At which point the system always boots to user space -- albeit with a bunch of warnings still (attached). The supposed "good" version doesn't end up with all those warnings deterministically, so I couldn't say if the warnings are expected due to recent changes or not (Arm64 QEMU emulation, 1 CPU, and lots of debugging tools on).
Does any of that make sense?
Marco, it makes all too much sense! :-/
Does the patch below help?
Thanx, Paul
------------------------------------------------------------------------

Quoted 8 lines

Quoted 5 lines
commit 444ef3bbd0f243b912fdfd51f326704f8ee872bf
Author: Peter Zijlstra <[email protected]>
Date:   Sat Aug 29 10:22:24 2020 -0700
sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled
My assumption is that this is a replacement for "rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled", right?

Hmmm... It was actually intended to be in addition.

Quoted 5 lines

That seems to have the same result (same test setup) as only reverting "rcu: Don't invoke..." does: still results in a bunch of workqueue lockup warnings and RCU stall warnings, but boots to user space. I attached a log. If the warnings are expected (are they?), then it looks fine to me.

No, they are not at all expected, but might be a different symptom of the original problem. Please see below.

Quoted 3 lines

(And just in case: with "rcu: Don't invoke..." and "sched/core:
Allow..." both applied I still get DEADLOCKs -- but that's probably expected.)

As noted earlier, it is a surprise. Could you please send me the console output?

Quoted 21 lines

Thanks,
-- Marco
Testing all events: OK
hrtimer: interrupt took 17120368 ns
Running tests again, along with the function tracer Running tests on all trace events:
Testing all events:
BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 12s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd
BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 17s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd
workqueue events_power_efficient: flags=0x82
pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3
pending: neigh_periodic_work

Quoted 3 lines

------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at kernel/rcu/tree_stall.h:758 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
WARNING: CPU: 0 PID: 1 at kernel/rcu/tree_stall.h:758 rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711

I have different line numbering, but the only warning that I see in this function is the one complaining that RCU has been ignoring a request to start a grace period for too long. This usually happens because the RCU grace-period kthread (named "rcu_preempt" in your case, but can also be named "rcu_sched") is being prevented from running, but can be caused by other things as well.

Quoted 10 lines

Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.0-rc3-next-20201110-00003-g920304642405-dirty #30
Hardware name: linux,dummy-virt (DT)
pstate: 20000085 (nzCv daIf -PAN -UAO -TCO BTYPE=--)
pc : rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
pc : rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711
lr : __xchg_mb arch/arm64/include/asm/cmpxchg.h:88 [inline]
lr : atomic_xchg include/asm-generic/atomic-instrumented.h:615 [inline]
lr : rcu_check_gp_start_stall kernel/rcu/tree_stall.h:751 [inline]
lr : rcu_check_gp_start_stall.isra.0+0x148/0x210 kernel/rcu/tree_stall.h:711

Two program counters and four link registers? Awesome! ;-)

Quoted 16 lines

sp : ffff800010003d20
x29: ffff800010003d20 x28: ffff274ac3a10000
x27: 0000000000000000 x26: ffff274b3dbe72d8
x25: ffffbcb867722000 x24: 0000000000000000
x23: 0000000000000000 x22: ffffbcb8681d1260
x21: ffffbcb86735b000 x20: ffffbcb867404440
x19: ffffbcb867404440 x18: 0000000000000123
x17: ffffbcb865d400f0 x16: 0000000000000002
x15: 0000000000000002 x14: 0000000000000000
x13: 003d090000000000 x12: 00001e8480000000
x11: ffffbcb867958980 x10: ffff800010003cf0
x9 : ffffbcb864f4b7c8 x8 : 0000000000000080
x7 : 0000000000000026 x6 : ffffbcb86774e4c0
x5 : 0000000000000000 x4 : 00000000d4001f4b
x3 : 0000000000000000 x2 : 0000000000000000
x1 : 0000000000000001 x0 : 0000000000000000

Quoted 5 lines

Call trace:
 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
 rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711
 rcu_core+0x168/0x9e0 kernel/rcu/tree.c:2719
 rcu_core_si+0x18/0x28 kernel/rcu/tree.c:2737

The RCU_SOFTIRQ handler is causing this checking to occur, for whatever that is worth.

Quoted 38 lines

 __do_softirq+0x188/0x6b4 kernel/softirq.c:298
 do_softirq_own_stack include/linux/interrupt.h:568 [inline]
 invoke_softirq kernel/softirq.c:393 [inline]
 __irq_exit_rcu kernel/softirq.c:423 [inline]
 irq_exit+0x1cc/0x1e0 kernel/softirq.c:447
 __handle_domain_irq+0xb4/0x130 kernel/irq/irqdesc.c:690
 handle_domain_irq include/linux/irqdesc.h:170 [inline]
 gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
 el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
 arch_local_irq_restore+0x8/0x10 arch/arm64/include/asm/irqflags.h:124
 release_probes kernel/tracepoint.c:113 [inline]
 tracepoint_remove_func kernel/tracepoint.c:315 [inline]
 tracepoint_probe_unregister+0x220/0x378 kernel/tracepoint.c:382
 trace_event_reg+0x58/0x150 kernel/trace/trace_events.c:298
 __ftrace_event_enable_disable+0x424/0x608 kernel/trace/trace_events.c:412
 ftrace_event_enable_disable kernel/trace/trace_events.c:495 [inline]
 __ftrace_set_clr_event_nolock+0x120/0x180 kernel/trace/trace_events.c:811
 __ftrace_set_clr_event+0x60/0x90 kernel/trace/trace_events.c:833
 event_trace_self_tests+0xd4/0x114 kernel/trace/trace_events.c:3661
 event_trace_self_test_with_function kernel/trace/trace_events.c:3734 [inline]
 event_trace_self_tests_init+0x88/0xa8 kernel/trace/trace_events.c:3747
 do_one_initcall+0xa4/0x500 init/main.c:1212
 do_initcall_level init/main.c:1285 [inline]
 do_initcalls init/main.c:1301 [inline]
 do_basic_setup init/main.c:1321 [inline]
 kernel_init_freeable+0x344/0x3c4 init/main.c:1521
 kernel_init+0x20/0x16c init/main.c:1410
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
irq event stamp: 3274113
hardirqs last  enabled at (3274112): [<ffffbcb864f8aee4>] rcu_core+0x974/0x9e0 kernel/rcu/tree.c:2716
hardirqs last disabled at (3274113): [<ffffbcb866233bf0>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
hardirqs last disabled at (3274113): [<ffffbcb866233bf0>] _raw_spin_lock_irqsave+0xb8/0x14c kernel/locking/spinlock.c:159
softirqs last  enabled at (3272576): [<ffffbcb864e10b80>] __do_softirq+0x630/0x6b4 kernel/softirq.c:325
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] do_softirq_own_stack include/linux/interrupt.h:568 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] invoke_softirq kernel/softirq.c:393 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] __irq_exit_rcu kernel/softirq.c:423 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] irq_exit+0x1cc/0x1e0 kernel/softirq.c:447
---[ end trace 902768efebf5a607 ]---

Quoted 1 line

rcu: rcu_preempt: wait state: RCU_GP_WAIT_GPS(1) ->state: 0x0 delta ->gp_activity 4452 ->gp_req_activity 3848 ->gp_wake_time 3848 ->gp_wake_seq 2696 ->gp_seq 2696 ->gp_seq_needed 2700 ->gp_flags 0x1

The last thing that RCU's grace-period kthread did was to go to sleep waiting for a grace-period request (RCU_GP_WAIT_GPS).

Quoted 9 lines

rcu: rcu_node 0:0 ->gp_seq 2696 ->gp_seq_needed 2700
rcu: RCU callbacks invoked since boot: 2583
rcu_tasks: RTGS_WAIT_CBS(11) since 567120 g:1 i:0/0 k.
rcu_tasks_rude: RTGS_WAIT_CBS(11) since 567155 g:1 i:0/1 k.
rcu_tasks_trace: RTGS_INIT(0) since 4295464549 g:0 i:0/0 k. N0 h:0/0/0
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=3752 jiffies, g=2705, q=8)
rcu: All QSes seen, last rcu_preempt kthread activity 557 (4295471128-4295470571), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 557 jiffies! g2705 f0x2 RCU_GP_CLEANUP(7) ->state=0x0 ->cpu=0

And here we see that RCU's grace-period kthread has in fact been starved.

This kthread is now in RCU_GP_CLEANUP, perhaps because of the wakeup that is sent in rcu_check_gp_kthread_starvation().

My current guess is that this is a consequence of the earlier failures, but who knows?

Thanx, Paul

Quoted 30 lines

rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack: 0 pid: 10 ppid: 2 flags:0x00000428
Call trace:
 __switch_to+0x10c/0x200 arch/arm64/kernel/process.c:578
 context_switch kernel/sched/core.c:3772 [inline]
 __schedule+0x2d8/0x980 kernel/sched/core.c:4521
 preempt_schedule_common+0x4c/0x1a8 kernel/sched/core.c:4680
 preempt_schedule+0x38/0x40 kernel/sched/core.c:4705
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x84/0x98 kernel/locking/spinlock.c:199
 rcu_gp_cleanup kernel/rcu/tree.c:2015 [inline]
 rcu_gp_kthread+0x1038/0x1bd8 kernel/rcu/tree.c:2119
 kthread+0x13c/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
OK
Testing ftrace filter: OK
Loading compiled-in X.509 certificates
input: gpio-keys as /devices/platform/gpio-keys/input/input0 ALSA device list:
No soundcards found.
TAP version 14
1..0
uart-pl011 9000000.pl011: no DMA platform data
EXT4-fs (sda): mounting ext3 file system using the ext4 subsystem EXT4-fs (sda): mounted filesystem with ordered data mode. Opts: (null)
VFS: Mounted root (ext3 filesystem) readonly on device 8:0.
devtmpfs: mounted
Freeing unused kernel memory: 8832K
Run /sbin/init as init process

Marco Elver

author maintainer

2020-11-19 17:03 UTC #26 lore raw

Quoted 70 lines · Paul E. McKenney

Quoted 49 lines · Marco Elver
Quoted 48 lines · Paul E. McKenney
Quoted 31 lines · Marco Elver
[...]
I think I figured out one piece of the puzzle. Bisection keeps pointing me at some -rcu merge commit, which kept throwing me off. Nor did it help that reproduction is a bit flaky. However, I think there are 2 independent problems, but the manifestation of 1 problem triggers the 2nd problem:
1. problem: slowed forward progress (workqueue lockup / RCU stall reports)
2. problem: DEADLOCK which causes complete system lockup
	| ...
	|        CPU0
	|        ----
	|   lock(rcu_node_0);
	|   <Interrupt>
	|     lock(rcu_node_0);
	| 
	|  *** DEADLOCK ***
	| 
	| 1 lock held by event_benchmark/105:
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581
	| ...
Problem 2 can with reasonable confidence (5 trials) be fixed by reverting:
rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled
Quoted 7 lines
At which point the system always boots to user space -- albeit with a bunch of warnings still (attached). The supposed "good" version doesn't end up with all those warnings deterministically, so I couldn't say if the warnings are expected due to recent changes or not (Arm64 QEMU emulation, 1 CPU, and lots of debugging tools on).
Does any of that make sense?
Marco, it makes all too much sense! :-/
Does the patch below help?
Thanx, Paul
------------------------------------------------------------------------
Quoted 8 lines
Quoted 5 lines
commit 444ef3bbd0f243b912fdfd51f326704f8ee872bf
Author: Peter Zijlstra <[email protected]>
Date:   Sat Aug 29 10:22:24 2020 -0700
sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled
My assumption is that this is a replacement for "rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled", right?
Hmmm... It was actually intended to be in addition.
Quoted 5 lines
That seems to have the same result (same test setup) as only reverting "rcu: Don't invoke..." does: still results in a bunch of workqueue lockup warnings and RCU stall warnings, but boots to user space. I attached a log. If the warnings are expected (are they?), then it looks fine to me.
No, they are not at all expected, but might be a different symptom of the original problem. Please see below.

Quoted 6 lines

Quoted 3 lines
(And just in case: with "rcu: Don't invoke..." and "sched/core:
Allow..." both applied I still get DEADLOCKs -- but that's probably expected.)
As noted earlier, it is a surprise. Could you please send me the console output?

I've attached the output of a run with both commits applied.

Quoted 22 lines

Quoted 18 lines
Testing all events: OK
hrtimer: interrupt took 17120368 ns
Running tests again, along with the function tracer Running tests on all trace events:
Testing all events:
BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 12s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd
BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 17s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd
workqueue events_power_efficient: flags=0x82
pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3
pending: neigh_periodic_work
Quoted 3 lines
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at kernel/rcu/tree_stall.h:758 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
WARNING: CPU: 0 PID: 1 at kernel/rcu/tree_stall.h:758 rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711

Quoted 1 line

I have different line numbering,

This is still using next-20201110. I'll rerun with latest -next as well.

Quoted 18 lines

but the only warning that I see in this
function is the one complaining that RCU has been ignoring a request to start a grace period for too long. This usually happens because the RCU grace-period kthread (named "rcu_preempt" in your case, but can also be named "rcu_sched") is being prevented from running, but can be caused by other things as well.
Quoted 10 lines
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.0-rc3-next-20201110-00003-g920304642405-dirty #30
Hardware name: linux,dummy-virt (DT)
pstate: 20000085 (nzCv daIf -PAN -UAO -TCO BTYPE=--)
pc : rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
pc : rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711
lr : __xchg_mb arch/arm64/include/asm/cmpxchg.h:88 [inline]
lr : atomic_xchg include/asm-generic/atomic-instrumented.h:615 [inline]
lr : rcu_check_gp_start_stall kernel/rcu/tree_stall.h:751 [inline]
lr : rcu_check_gp_start_stall.isra.0+0x148/0x210 kernel/rcu/tree_stall.h:711

Quoted 1 line

Two program counters and four link registers? Awesome! ;-)

Ah I'm using syzkaller's symbolizer, which duplicates lines if there was an inline function (remove all the "[inline]" and it should make sense, but the "[inline]" tell you the actual line). Obviously for things like this it's a bit unintuitive. :-)

Quoted 78 lines

Quoted 16 lines
sp : ffff800010003d20
x29: ffff800010003d20 x28: ffff274ac3a10000
x27: 0000000000000000 x26: ffff274b3dbe72d8
x25: ffffbcb867722000 x24: 0000000000000000
x23: 0000000000000000 x22: ffffbcb8681d1260
x21: ffffbcb86735b000 x20: ffffbcb867404440
x19: ffffbcb867404440 x18: 0000000000000123
x17: ffffbcb865d400f0 x16: 0000000000000002
x15: 0000000000000002 x14: 0000000000000000
x13: 003d090000000000 x12: 00001e8480000000
x11: ffffbcb867958980 x10: ffff800010003cf0
x9 : ffffbcb864f4b7c8 x8 : 0000000000000080
x7 : 0000000000000026 x6 : ffffbcb86774e4c0
x5 : 0000000000000000 x4 : 00000000d4001f4b
x3 : 0000000000000000 x2 : 0000000000000000
x1 : 0000000000000001 x0 : 0000000000000000
Quoted 5 lines
Call trace:
 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
 rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711
 rcu_core+0x168/0x9e0 kernel/rcu/tree.c:2719
 rcu_core_si+0x18/0x28 kernel/rcu/tree.c:2737
The RCU_SOFTIRQ handler is causing this checking to occur, for whatever that is worth.
Quoted 38 lines
 __do_softirq+0x188/0x6b4 kernel/softirq.c:298
 do_softirq_own_stack include/linux/interrupt.h:568 [inline]
 invoke_softirq kernel/softirq.c:393 [inline]
 __irq_exit_rcu kernel/softirq.c:423 [inline]
 irq_exit+0x1cc/0x1e0 kernel/softirq.c:447
 __handle_domain_irq+0xb4/0x130 kernel/irq/irqdesc.c:690
 handle_domain_irq include/linux/irqdesc.h:170 [inline]
 gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
 el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
 arch_local_irq_restore+0x8/0x10 arch/arm64/include/asm/irqflags.h:124
 release_probes kernel/tracepoint.c:113 [inline]
 tracepoint_remove_func kernel/tracepoint.c:315 [inline]
 tracepoint_probe_unregister+0x220/0x378 kernel/tracepoint.c:382
 trace_event_reg+0x58/0x150 kernel/trace/trace_events.c:298
 __ftrace_event_enable_disable+0x424/0x608 kernel/trace/trace_events.c:412
 ftrace_event_enable_disable kernel/trace/trace_events.c:495 [inline]
 __ftrace_set_clr_event_nolock+0x120/0x180 kernel/trace/trace_events.c:811
 __ftrace_set_clr_event+0x60/0x90 kernel/trace/trace_events.c:833
 event_trace_self_tests+0xd4/0x114 kernel/trace/trace_events.c:3661
 event_trace_self_test_with_function kernel/trace/trace_events.c:3734 [inline]
 event_trace_self_tests_init+0x88/0xa8 kernel/trace/trace_events.c:3747
 do_one_initcall+0xa4/0x500 init/main.c:1212
 do_initcall_level init/main.c:1285 [inline]
 do_initcalls init/main.c:1301 [inline]
 do_basic_setup init/main.c:1321 [inline]
 kernel_init_freeable+0x344/0x3c4 init/main.c:1521
 kernel_init+0x20/0x16c init/main.c:1410
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
irq event stamp: 3274113
hardirqs last  enabled at (3274112): [<ffffbcb864f8aee4>] rcu_core+0x974/0x9e0 kernel/rcu/tree.c:2716
hardirqs last disabled at (3274113): [<ffffbcb866233bf0>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
hardirqs last disabled at (3274113): [<ffffbcb866233bf0>] _raw_spin_lock_irqsave+0xb8/0x14c kernel/locking/spinlock.c:159
softirqs last  enabled at (3272576): [<ffffbcb864e10b80>] __do_softirq+0x630/0x6b4 kernel/softirq.c:325
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] do_softirq_own_stack include/linux/interrupt.h:568 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] invoke_softirq kernel/softirq.c:393 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] __irq_exit_rcu kernel/softirq.c:423 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] irq_exit+0x1cc/0x1e0 kernel/softirq.c:447
---[ end trace 902768efebf5a607 ]---
Quoted 1 line
rcu: rcu_preempt: wait state: RCU_GP_WAIT_GPS(1) ->state: 0x0 delta ->gp_activity 4452 ->gp_req_activity 3848 ->gp_wake_time 3848 ->gp_wake_seq 2696 ->gp_seq 2696 ->gp_seq_needed 2700 ->gp_flags 0x1
The last thing that RCU's grace-period kthread did was to go to sleep waiting for a grace-period request (RCU_GP_WAIT_GPS).
Quoted 9 lines
rcu: rcu_node 0:0 ->gp_seq 2696 ->gp_seq_needed 2700
rcu: RCU callbacks invoked since boot: 2583
rcu_tasks: RTGS_WAIT_CBS(11) since 567120 g:1 i:0/0 k.
rcu_tasks_rude: RTGS_WAIT_CBS(11) since 567155 g:1 i:0/1 k.
rcu_tasks_trace: RTGS_INIT(0) since 4295464549 g:0 i:0/0 k. N0 h:0/0/0
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=3752 jiffies, g=2705, q=8)
rcu: All QSes seen, last rcu_preempt kthread activity 557 (4295471128-4295470571), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 557 jiffies! g2705 f0x2 RCU_GP_CLEANUP(7) ->state=0x0 ->cpu=0

Quoted 7 lines

And here we see that RCU's grace-period kthread has in fact been starved.
This kthread is now in RCU_GP_CLEANUP, perhaps because of the wakeup that is sent in rcu_check_gp_kthread_starvation().
My current guess is that this is a consequence of the earlier failures, but who knows?

I can try bisection again, or reverting some commits that might be suspicious? But we'd need some selection of suspicious commits.

Thanks,
-- Marco

Testing all events: OK
Running tests again, along with the function tracer Running tests on all trace events:
Testing all events:
hrtimer: interrupt took 10901376 ns

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 12s!

BUG: workqueue lockup - pool cpus=0 flags=0x5 nice=0 stuck for 11s!

Showing busy workqueues and worker pools:
workqueue events_power_efficient: flags=0x82
pwq 2: cpus=0 flags=0x5 nice=0 active=3/256 refcnt=5
in-flight: 99:check_lifetime
pending: neigh_periodic_work, do_cache_clean
pool 2: cpus=0 flags=0x5 nice=0 hung=11s workers=2 manager: 61

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!

Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd
workqueue events_power_efficient: flags=0x82
pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3
in-flight: 107:check_lifetime
pool 2: cpus=0 flags=0x4 nice=0 hung=8s workers=4 idle: 99 106 61

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 20s!

Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd
workqueue events_power_efficient: flags=0x82
pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3
in-flight: 107:check_lifetime
pool 2: cpus=0 flags=0x4 nice=0 hung=2s workers=4 idle: 99 106 61

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=3752 jiffies, g=2501, q=1)

rcu: All QSes seen, last rcu_preempt kthread activity 3472 (4295298049-4295294577), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 3472 jiffies! g2501 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:I stack: 0 pid: 10 ppid: 2 flags:0x0000042a

Call trace:
 dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
 sched_show_task kernel/sched/core.c:6444 [inline]
 sched_show_task+0x1fc/0x228 kernel/sched/core.c:6419
 rcu_check_gp_kthread_starvation+0xc8/0xe4 kernel/rcu/tree_stall.h:465
 print_other_cpu_stall kernel/rcu/tree_stall.h:532 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
 rcu_pending kernel/rcu/tree.c:3752 [inline]
 rcu_sched_clock_irq+0xc2c/0xd40 kernel/rcu/tree.c:2581
 update_process_times+0x6c/0xb8 kernel/time/timer.c:1709
 tick_sched_handle.isra.0+0x58/0x88 kernel/time/tick-sched.c:176
 tick_sched_timer+0x68/0xe0 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
 __hrtimer_run_queues+0x288/0x730 kernel/time/hrtimer.c:1583
 hrtimer_interrupt+0x114/0x288 kernel/time/hrtimer.c:1645
 timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline]
 arch_timer_handler_virt+0x50/0x70 drivers/clocksource/arm_arch_timer.c:658
 handle_percpu_devid_irq+0x104/0x4c0 kernel/irq/chip.c:930
 generic_handle_irq_desc include/linux/irqdesc.h:152 [inline]
 generic_handle_irq+0x54/0x78 kernel/irq/irqdesc.c:650
 __handle_domain_irq+0xac/0x130 kernel/irq/irqdesc.c:687
 handle_domain_irq include/linux/irqdesc.h:170 [inline]
 gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
 el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:124 [inline]
 rcu_irq_enter_irqson+0x40/0x78 kernel/rcu/tree.c:1078
 trace_preempt_disable_rcuidle include/trace/events/preemptirq.h:51 [inline]
 trace_preempt_off+0x108/0x1f8 kernel/trace/trace_preemptirq.c:130
 preempt_latency_start kernel/sched/core.c:4163 [inline]
 preempt_latency_start kernel/sched/core.c:4156 [inline]
 preempt_schedule_common+0x170/0x1a8 kernel/sched/core.c:4679
 preempt_schedule+0x38/0x40 kernel/sched/core.c:4705
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
 _raw_spin_unlock_irqrestore+0x90/0xa0 kernel/locking/spinlock.c:191
 prepare_to_swait_event+0x84/0xe8 kernel/sched/swait.c:120
 rcu_gp_fqs_loop kernel/rcu/tree.c:1942 [inline]
 rcu_gp_kthread+0x630/0x1bd8 kernel/rcu/tree.c:2115
 kthread+0x13c/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961

================================
WARNING: inconsistent lock state
5.10.0-rc3-next-20201110-00003-g891a69a3957e #1 Not tainted
--------------------------------
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
rcu_preempt/10 [HC0[0]:SC0[0]:HE0:SE1] takes:
ffffb80c721e4458 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline] ffffb80c721e4458 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:652 [inline] ffffb80c721e4458 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline] ffffb80c721e4458 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581 {IN-HARDIRQ-W} state was registered at:

  mark_lock kernel/locking/lockdep.c:4374 [inline]
  mark_usage kernel/locking/lockdep.c:4302 [inline]
  __lock_acquire+0xaa8/0x1a50 kernel/locking/lockdep.c:4785
  lock_acquire kernel/locking/lockdep.c:5436 [inline]
  lock_acquire+0x268/0x508 kernel/locking/lockdep.c:5401
  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
  _raw_spin_lock_irqsave+0x78/0x14c kernel/locking/spinlock.c:159
  print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline]
  check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
  rcu_pending kernel/rcu/tree.c:3752 [inline]
  rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581
  update_process_times+0x6c/0xb8 kernel/time/timer.c:1709
  tick_sched_handle.isra.0+0x58/0x88 kernel/time/tick-sched.c:176
  tick_sched_timer+0x68/0xe0 kernel/time/tick-sched.c:1328
  __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
  __hrtimer_run_queues+0x288/0x730 kernel/time/hrtimer.c:1583
  hrtimer_interrupt+0x114/0x288 kernel/time/hrtimer.c:1645
  timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline]
  arch_timer_handler_virt+0x50/0x70 drivers/clocksource/arm_arch_timer.c:658
  handle_percpu_devid_irq+0x104/0x4c0 kernel/irq/chip.c:930
  generic_handle_irq_desc include/linux/irqdesc.h:152 [inline]
  generic_handle_irq+0x54/0x78 kernel/irq/irqdesc.c:650
  __handle_domain_irq+0xac/0x130 kernel/irq/irqdesc.c:687
  handle_domain_irq include/linux/irqdesc.h:170 [inline]
  gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
  el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
  arch_local_irq_restore arch/arm64/include/asm/irqflags.h:124 [inline]
  rcu_irq_enter_irqson+0x40/0x78 kernel/rcu/tree.c:1078
  trace_preempt_disable_rcuidle include/trace/events/preemptirq.h:51 [inline]
  trace_preempt_off+0x108/0x1f8 kernel/trace/trace_preemptirq.c:130
  preempt_latency_start kernel/sched/core.c:4163 [inline]
  preempt_latency_start kernel/sched/core.c:4156 [inline]
  preempt_schedule_common+0x170/0x1a8 kernel/sched/core.c:4679
  preempt_schedule+0x38/0x40 kernel/sched/core.c:4705
  __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
  _raw_spin_unlock_irqrestore+0x90/0xa0 kernel/locking/spinlock.c:191
  prepare_to_swait_event+0x84/0xe8 kernel/sched/swait.c:120
  rcu_gp_fqs_loop kernel/rcu/tree.c:1942 [inline]
  rcu_gp_kthread+0x630/0x1bd8 kernel/rcu/tree.c:2115
  kthread+0x13c/0x188 kernel/kthread.c:292
  ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
irq event stamp: 43978
hardirqs last  enabled at (43977): [<ffffb80c6fd89db4>] rcu_irq_enter_irqson+0x64/0x78 kernel/rcu/tree.c:1078
hardirqs last disabled at (43978): [<ffffb80c6fc123c0>] el1_irq+0x80/0x180 arch/arm64/kernel/entry.S:648
softirqs last  enabled at (43682): [<ffffb80c6fc10b80>] __do_softirq+0x630/0x6b4 kernel/softirq.c:325
softirqs last disabled at (43673): [<ffffb80c6fcc61c4>] do_softirq_own_stack include/linux/interrupt.h:568 [inline]
softirqs last disabled at (43673): [<ffffb80c6fcc61c4>] invoke_softirq kernel/softirq.c:393 [inline]
softirqs last disabled at (43673): [<ffffb80c6fcc61c4>] __irq_exit_rcu kernel/softirq.c:423 [inline]
softirqs last disabled at (43673): [<ffffb80c6fcc61c4>] irq_exit+0x1cc/0x1e0 kernel/softirq.c:447

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0
       ----
  lock(rcu_node_0);
  <Interrupt>
    lock(rcu_node_0);

*** DEADLOCK ***

1 lock held by rcu_preempt/10:
#0: ffffb80c721e4458 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline] #0: ffffb80c721e4458 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:652 [inline] #0: ffffb80c721e4458 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline] #0: ffffb80c721e4458 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581

stack backtrace:
CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.10.0-rc3-next-20201110-00003-g891a69a3957e #1
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x140/0x1bc lib/dump_stack.c:118
 print_usage_bug kernel/locking/lockdep.c:3739 [inline]
 print_usage_bug+0x2a0/0x2f0 kernel/locking/lockdep.c:3706
 valid_state kernel/locking/lockdep.c:3750 [inline]
 mark_lock_irq kernel/locking/lockdep.c:3953 [inline]
 mark_lock.part.0+0x438/0x4e8 kernel/locking/lockdep.c:4410
 mark_lock kernel/locking/lockdep.c:4008 [inline]
 mark_held_locks+0x54/0x90 kernel/locking/lockdep.c:4011
 __trace_hardirqs_on_caller kernel/locking/lockdep.c:4029 [inline]
 lockdep_hardirqs_on_prepare+0xe0/0x290 kernel/locking/lockdep.c:4097
 trace_hardirqs_on+0x90/0x370 kernel/trace/trace_preemptirq.c:49
 el1_irq+0xdc/0x180 arch/arm64/kernel/entry.S:685
 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:124 [inline]
 rcu_irq_enter_irqson+0x40/0x78 kernel/rcu/tree.c:1078
 trace_preempt_disable_rcuidle include/trace/events/preemptirq.h:51 [inline]
 trace_preempt_off+0x108/0x1f8 kernel/trace/trace_preemptirq.c:130
 preempt_latency_start kernel/sched/core.c:4163 [inline]
 preempt_latency_start kernel/sched/core.c:4156 [inline]
 preempt_schedule_common+0x170/0x1a8 kernel/sched/core.c:4679
 preempt_schedule+0x38/0x40 kernel/sched/core.c:4705
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
 _raw_spin_unlock_irqrestore+0x90/0xa0 kernel/locking/spinlock.c:191
 prepare_to_swait_event+0x84/0xe8 kernel/sched/swait.c:120
 rcu_gp_fqs_loop kernel/rcu/tree.c:1942 [inline]
 rcu_gp_kthread+0x630/0x1bd8 kernel/rcu/tree.c:2115
 kthread+0x13c/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
BUG: scheduling while atomic: rcu_preempt/10/0x00000002
INFO: lockdep is turned off.
Modules linked in:
Preemption disabled at:
[<ffffb80c71009bf8>] preempt_schedule+0x38/0x40 kernel/sched/core.c:4705
CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.10.0-rc3-next-20201110-00003-g891a69a3957e #1
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x140/0x1bc lib/dump_stack.c:118
 __schedule_bug+0xcc/0xe0 kernel/sched/core.c:4261
 schedule_debug kernel/sched/core.c:4288 [inline]
 __schedule+0x888/0x970 kernel/sched/core.c:4416
 preempt_schedule_common+0x4c/0x1a8 kernel/sched/core.c:4680
 preempt_schedule+0x38/0x40 kernel/sched/core.c:4705
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
 _raw_spin_unlock_irqrestore+0x90/0xa0 kernel/locking/spinlock.c:191
 prepare_to_swait_event+0x84/0xe8 kernel/sched/swait.c:120
 rcu_gp_fqs_loop kernel/rcu/tree.c:1942 [inline]
 rcu_gp_kthread+0x630/0x1bd8 kernel/rcu/tree.c:2115
 kthread+0x13c/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961

Paul E. McKenney

maintainer

2020-11-19 18:48 UTC #27 lore raw

Quoted 71 lines · Marco Elver

Quoted 70 lines · Paul E. McKenney
Quoted 49 lines · Marco Elver
Quoted 48 lines · Paul E. McKenney
Quoted 31 lines · Marco Elver
[...]
I think I figured out one piece of the puzzle. Bisection keeps pointing me at some -rcu merge commit, which kept throwing me off. Nor did it help that reproduction is a bit flaky. However, I think there are 2 independent problems, but the manifestation of 1 problem triggers the 2nd problem:
1. problem: slowed forward progress (workqueue lockup / RCU stall reports)
2. problem: DEADLOCK which causes complete system lockup
	| ...
	|        CPU0
	|        ----
	|   lock(rcu_node_0);
	|   <Interrupt>
	|     lock(rcu_node_0);
	| 
	|  *** DEADLOCK ***
	| 
	| 1 lock held by event_benchmark/105:
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581
	| ...
Problem 2 can with reasonable confidence (5 trials) be fixed by reverting:
rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled
Quoted 7 lines
At which point the system always boots to user space -- albeit with a bunch of warnings still (attached). The supposed "good" version doesn't end up with all those warnings deterministically, so I couldn't say if the warnings are expected due to recent changes or not (Arm64 QEMU emulation, 1 CPU, and lots of debugging tools on).
Does any of that make sense?
Marco, it makes all too much sense! :-/
Does the patch below help?
Thanx, Paul
------------------------------------------------------------------------
Quoted 8 lines
Quoted 5 lines
commit 444ef3bbd0f243b912fdfd51f326704f8ee872bf
Author: Peter Zijlstra <[email protected]>
Date:   Sat Aug 29 10:22:24 2020 -0700
sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled
My assumption is that this is a replacement for "rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled", right?
Hmmm... It was actually intended to be in addition.
Quoted 5 lines
That seems to have the same result (same test setup) as only reverting "rcu: Don't invoke..." does: still results in a bunch of workqueue lockup warnings and RCU stall warnings, but boots to user space. I attached a log. If the warnings are expected (are they?), then it looks fine to me.
No, they are not at all expected, but might be a different symptom of the original problem. Please see below.

Quoted 8 lines

Quoted 6 lines
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(And just in case: with "rcu: Don't invoke..." and "sched/core:
Allow..." both applied I still get DEADLOCKs -- but that's probably expected.)
As noted earlier, it is a surprise. Could you please send me the console output?
I've attached the output of a run with both commits applied.

Got it, thank you!

Quoted 22 lines

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Testing all events: OK
hrtimer: interrupt took 17120368 ns
Running tests again, along with the function tracer Running tests on all trace events:
Testing all events:
BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 12s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd
BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 17s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd
workqueue events_power_efficient: flags=0x82
pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3
pending: neigh_periodic_work
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at kernel/rcu/tree_stall.h:758 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
WARNING: CPU: 0 PID: 1 at kernel/rcu/tree_stall.h:758 rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711

Quoted 3 lines

Quoted 1 line
I have different line numbering,
This is still using next-20201110. I'll rerun with latest -next as well.

No problem, as it looks like next-20201105 is a reasonable approximation.

Quoted 18 lines

Quoted 18 lines
but the only warning that I see in this
function is the one complaining that RCU has been ignoring a request to start a grace period for too long. This usually happens because the RCU grace-period kthread (named "rcu_preempt" in your case, but can also be named "rcu_sched") is being prevented from running, but can be caused by other things as well.
Quoted 10 lines
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.0-rc3-next-20201110-00003-g920304642405-dirty #30
Hardware name: linux,dummy-virt (DT)
pstate: 20000085 (nzCv daIf -PAN -UAO -TCO BTYPE=--)
pc : rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
pc : rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711
lr : __xchg_mb arch/arm64/include/asm/cmpxchg.h:88 [inline]
lr : atomic_xchg include/asm-generic/atomic-instrumented.h:615 [inline]
lr : rcu_check_gp_start_stall kernel/rcu/tree_stall.h:751 [inline]
lr : rcu_check_gp_start_stall.isra.0+0x148/0x210 kernel/rcu/tree_stall.h:711

Quoted 6 lines

Quoted 1 line
Two program counters and four link registers? Awesome! ;-)
Ah I'm using syzkaller's symbolizer, which duplicates lines if there was an inline function (remove all the "[inline]" and it should make sense, but the "[inline]" tell you the actual line). Obviously for things like this it's a bit unintuitive. :-)

Very useful, though, and a big THANK YOU to those who made it happen!

Quoted 80 lines

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sp : ffff800010003d20
x29: ffff800010003d20 x28: ffff274ac3a10000
x27: 0000000000000000 x26: ffff274b3dbe72d8
x25: ffffbcb867722000 x24: 0000000000000000
x23: 0000000000000000 x22: ffffbcb8681d1260
x21: ffffbcb86735b000 x20: ffffbcb867404440
x19: ffffbcb867404440 x18: 0000000000000123
x17: ffffbcb865d400f0 x16: 0000000000000002
x15: 0000000000000002 x14: 0000000000000000
x13: 003d090000000000 x12: 00001e8480000000
x11: ffffbcb867958980 x10: ffff800010003cf0
x9 : ffffbcb864f4b7c8 x8 : 0000000000000080
x7 : 0000000000000026 x6 : ffffbcb86774e4c0
x5 : 0000000000000000 x4 : 00000000d4001f4b
x3 : 0000000000000000 x2 : 0000000000000000
x1 : 0000000000000001 x0 : 0000000000000000
Quoted 5 lines
Call trace:
 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
 rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711
 rcu_core+0x168/0x9e0 kernel/rcu/tree.c:2719
 rcu_core_si+0x18/0x28 kernel/rcu/tree.c:2737
The RCU_SOFTIRQ handler is causing this checking to occur, for whatever that is worth.
Quoted 38 lines
 __do_softirq+0x188/0x6b4 kernel/softirq.c:298
 do_softirq_own_stack include/linux/interrupt.h:568 [inline]
 invoke_softirq kernel/softirq.c:393 [inline]
 __irq_exit_rcu kernel/softirq.c:423 [inline]
 irq_exit+0x1cc/0x1e0 kernel/softirq.c:447
 __handle_domain_irq+0xb4/0x130 kernel/irq/irqdesc.c:690
 handle_domain_irq include/linux/irqdesc.h:170 [inline]
 gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
 el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
 arch_local_irq_restore+0x8/0x10 arch/arm64/include/asm/irqflags.h:124
 release_probes kernel/tracepoint.c:113 [inline]
 tracepoint_remove_func kernel/tracepoint.c:315 [inline]
 tracepoint_probe_unregister+0x220/0x378 kernel/tracepoint.c:382
 trace_event_reg+0x58/0x150 kernel/trace/trace_events.c:298
 __ftrace_event_enable_disable+0x424/0x608 kernel/trace/trace_events.c:412
 ftrace_event_enable_disable kernel/trace/trace_events.c:495 [inline]
 __ftrace_set_clr_event_nolock+0x120/0x180 kernel/trace/trace_events.c:811
 __ftrace_set_clr_event+0x60/0x90 kernel/trace/trace_events.c:833
 event_trace_self_tests+0xd4/0x114 kernel/trace/trace_events.c:3661
 event_trace_self_test_with_function kernel/trace/trace_events.c:3734 [inline]
 event_trace_self_tests_init+0x88/0xa8 kernel/trace/trace_events.c:3747
 do_one_initcall+0xa4/0x500 init/main.c:1212
 do_initcall_level init/main.c:1285 [inline]
 do_initcalls init/main.c:1301 [inline]
 do_basic_setup init/main.c:1321 [inline]
 kernel_init_freeable+0x344/0x3c4 init/main.c:1521
 kernel_init+0x20/0x16c init/main.c:1410
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
irq event stamp: 3274113
hardirqs last  enabled at (3274112): [<ffffbcb864f8aee4>] rcu_core+0x974/0x9e0 kernel/rcu/tree.c:2716
hardirqs last disabled at (3274113): [<ffffbcb866233bf0>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
hardirqs last disabled at (3274113): [<ffffbcb866233bf0>] _raw_spin_lock_irqsave+0xb8/0x14c kernel/locking/spinlock.c:159
softirqs last  enabled at (3272576): [<ffffbcb864e10b80>] __do_softirq+0x630/0x6b4 kernel/softirq.c:325
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] do_softirq_own_stack include/linux/interrupt.h:568 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] invoke_softirq kernel/softirq.c:393 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] __irq_exit_rcu kernel/softirq.c:423 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] irq_exit+0x1cc/0x1e0 kernel/softirq.c:447
---[ end trace 902768efebf5a607 ]---
Quoted 1 line
rcu: rcu_preempt: wait state: RCU_GP_WAIT_GPS(1) ->state: 0x0 delta ->gp_activity 4452 ->gp_req_activity 3848 ->gp_wake_time 3848 ->gp_wake_seq 2696 ->gp_seq 2696 ->gp_seq_needed 2700 ->gp_flags 0x1
The last thing that RCU's grace-period kthread did was to go to sleep waiting for a grace-period request (RCU_GP_WAIT_GPS).
Quoted 9 lines
rcu: rcu_node 0:0 ->gp_seq 2696 ->gp_seq_needed 2700
rcu: RCU callbacks invoked since boot: 2583
rcu_tasks: RTGS_WAIT_CBS(11) since 567120 g:1 i:0/0 k.
rcu_tasks_rude: RTGS_WAIT_CBS(11) since 567155 g:1 i:0/1 k.
rcu_tasks_trace: RTGS_INIT(0) since 4295464549 g:0 i:0/0 k. N0 h:0/0/0
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=3752 jiffies, g=2705, q=8)
rcu: All QSes seen, last rcu_preempt kthread activity 557 (4295471128-4295470571), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 557 jiffies! g2705 f0x2 RCU_GP_CLEANUP(7) ->state=0x0 ->cpu=0
And here we see that RCU's grace-period kthread has in fact been starved.

Quoted 8 lines

Quoted 5 lines
This kthread is now in RCU_GP_CLEANUP, perhaps because of the wakeup that is sent in rcu_check_gp_kthread_starvation().
My current guess is that this is a consequence of the earlier failures, but who knows?
I can try bisection again, or reverting some commits that might be suspicious? But we'd need some selection of suspicious commits.

The report claims that one of the rcu_node ->lock fields is held with interrupts enabled, which would indeed be bad. Except that all of the stack traces that it shows have these locks held within the scheduling-clock interrupt handler. Now with the "rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled" but without the "sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled" commit, I understand why. With both, I don't see how this happens.

At this point, I am reduced to adding lockdep_assert_irqs_disabled() calls at various points in that code, as shown in the patch below.

At this point, I would guess that your first priority would be the initial bug rather than this following issue, but you never know, this might well help diagnose the initial bug.

Thanx, Paul

------------------------------------------------------------------------

commit ccedf00693ef60f7c06d23490fc41bb60dd43dc3

Author: Paul E. McKenney <[email protected]>
Date:   Thu Nov 19 10:13:06 2020 -0800

rcu: Add lockdep_assert_irqs_disabled() to rcu_sched_clock_irq() and callees

This commit adds a number of lockdep_assert_irqs_disabled() calls to rcu_sched_clock_irq() and a number of the functions that it calls. The point of this is to help track down a situation where lockdep appears to be insisting that interrupts are enabled within these functions, which should only ever be invoked from the scheduling-clock interrupt handler.

Link https://lore.kernel.org/lkml/[email protected]/ open here

Signed-off-by Paul E. McKenney <[email protected]>

kernel/rcu/tree.c +4 -0

index 2b3274c..1d956f9 100644
@@ -2580,6 +2580,7 @@ static void rcu_do_batch(struct rcu_data *rdp)
 void rcu_sched_clock_irq(int user)
 {
 	trace_rcu_utilization(TPS("Start scheduler-tick"));
+	lockdep_assert_irqs_disabled();
 	raw_cpu_inc(rcu_data.ticks_this_gp);
 	/* The load-acquire pairs with the store-release setting to true. */
 	if (smp_load_acquire(this_cpu_ptr(&rcu_data.rcu_urgent_qs))) {

@@ -2593,6 +2594,7 @@ void rcu_sched_clock_irq(int user)
 	rcu_flavor_sched_clock_irq(user);
 	if (rcu_pending(user))
 		invoke_rcu_core();
+	lockdep_assert_irqs_disabled();
 
 	trace_rcu_utilization(TPS("End scheduler-tick"));
 }

@@ -3761,6 +3763,8 @@ static int rcu_pending(int user)
 	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
 	struct rcu_node *rnp = rdp->mynode;
 
+	lockdep_assert_irqs_disabled();
+
 	/* Check for CPU stalls, if enabled. */
 	check_cpu_stall(rdp);

kernel/rcu/tree_plugin.h +1 -0

index 642ebd6..f7aa41c 100644
@@ -682,6 +682,7 @@ static void rcu_flavor_sched_clock_irq(int user)
 {
 	struct task_struct *t = current;
 
+	lockdep_assert_irqs_disabled();
 	if (user || rcu_is_cpu_rrupt_from_idle()) {
 		rcu_note_voluntary_context_switch(current);
 	}

kernel/rcu/tree_stall.h +8 -0

index 4e3aecd..f276d8e 100644
@@ -267,6 +267,7 @@ static int rcu_print_task_stall(struct rcu_node *rnp, unsigned long flags)
 	struct task_struct *t;
 	struct task_struct *ts[8];
 
+	lockdep_assert_irqs_disabled();
 	if (!rcu_preempt_blocked_readers_cgp(rnp))
 		return 0;
 	pr_err("\tTasks blocked on level-%d rcu_node (CPUs %d-%d):",

@@ -291,6 +292,7 @@ static int rcu_print_task_stall(struct rcu_node *rnp, unsigned long flags)
 				".q"[rscr.rs.b.need_qs],
 				".e"[rscr.rs.b.exp_hint],
 				".l"[rscr.on_blkd_list]);
+		lockdep_assert_irqs_disabled();
 		put_task_struct(t);
 		ndetected++;
 	}

@@ -527,6 +529,8 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps)
 	struct rcu_node *rnp;
 	long totqlen = 0;
 
+	lockdep_assert_irqs_disabled();
+
 	/* Kick and suppress, if so configured. */
 	rcu_stall_kick_kthreads();
 	if (rcu_stall_is_suppressed())

@@ -548,6 +552,7 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps)
 				}
 		}
 		ndetected += rcu_print_task_stall(rnp, flags); // Releases rnp->lock.
+		lockdep_assert_irqs_disabled();
 	}
 
 	for_each_possible_cpu(cpu)

@@ -594,6 +599,8 @@ static void print_cpu_stall(unsigned long gps)
 	struct rcu_node *rnp = rcu_get_root();
 	long totqlen = 0;
 
+	lockdep_assert_irqs_disabled();
+
 	/* Kick and suppress, if so configured. */
 	rcu_stall_kick_kthreads();
 	if (rcu_stall_is_suppressed())

@@ -649,6 +656,7 @@ static void check_cpu_stall(struct rcu_data *rdp)
 	unsigned long js;
 	struct rcu_node *rnp;
 
+	lockdep_assert_irqs_disabled();
 	if ((rcu_stall_is_suppressed() && !READ_ONCE(rcu_kick_kthreads)) ||
 	    !rcu_gp_in_progress())
 		return;

Marco Elver

author maintainer

2020-11-19 19:38 UTC #28 lore raw

linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 227 lines · Paul E. McKenney

Quoted 71 lines · Marco Elver
Quoted 70 lines · Paul E. McKenney
Quoted 49 lines · Marco Elver
Quoted 48 lines · Paul E. McKenney
Quoted 31 lines · Marco Elver
[...]
I think I figured out one piece of the puzzle. Bisection keeps pointing me at some -rcu merge commit, which kept throwing me off. Nor did it help that reproduction is a bit flaky. However, I think there are 2 independent problems, but the manifestation of 1 problem triggers the 2nd problem:
1. problem: slowed forward progress (workqueue lockup / RCU stall reports)
2. problem: DEADLOCK which causes complete system lockup
	| ...
	|        CPU0
	|        ----
	|   lock(rcu_node_0);
	|   <Interrupt>
	|     lock(rcu_node_0);
	| 
	|  *** DEADLOCK ***
	| 
	| 1 lock held by event_benchmark/105:
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:493 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:652 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3752 [inline]
	|  #0: ffffbb6e0b804458 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x428/0xd40 kernel/rcu/tree.c:2581
	| ...
Problem 2 can with reasonable confidence (5 trials) be fixed by reverting:
rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled
Quoted 7 lines
At which point the system always boots to user space -- albeit with a bunch of warnings still (attached). The supposed "good" version doesn't end up with all those warnings deterministically, so I couldn't say if the warnings are expected due to recent changes or not (Arm64 QEMU emulation, 1 CPU, and lots of debugging tools on).
Does any of that make sense?
Marco, it makes all too much sense! :-/
Does the patch below help?
Thanx, Paul
------------------------------------------------------------------------
Quoted 8 lines
Quoted 5 lines
commit 444ef3bbd0f243b912fdfd51f326704f8ee872bf
Author: Peter Zijlstra <[email protected]>
Date:   Sat Aug 29 10:22:24 2020 -0700
sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled
My assumption is that this is a replacement for "rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled", right?
Hmmm... It was actually intended to be in addition.
Quoted 5 lines
That seems to have the same result (same test setup) as only reverting "rcu: Don't invoke..." does: still results in a bunch of workqueue lockup warnings and RCU stall warnings, but boots to user space. I attached a log. If the warnings are expected (are they?), then it looks fine to me.
No, they are not at all expected, but might be a different symptom of the original problem. Please see below.
Quoted 8 lines
Quoted 6 lines
Quoted 3 lines
(And just in case: with "rcu: Don't invoke..." and "sched/core:
Allow..." both applied I still get DEADLOCKs -- but that's probably expected.)
As noted earlier, it is a surprise. Could you please send me the console output?
I've attached the output of a run with both commits applied.
Got it, thank you!
Quoted 22 lines
Quoted 22 lines
Quoted 21 lines
Testing all events: OK
hrtimer: interrupt took 17120368 ns
Running tests again, along with the function tracer Running tests on all trace events:
Testing all events:
BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 12s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd
BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 17s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd
workqueue events_power_efficient: flags=0x82
pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3
pending: neigh_periodic_work
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at kernel/rcu/tree_stall.h:758 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
WARNING: CPU: 0 PID: 1 at kernel/rcu/tree_stall.h:758 rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711
Quoted 3 lines
Quoted 1 line
I have different line numbering,
This is still using next-20201110. I'll rerun with latest -next as well.
No problem, as it looks like next-20201105 is a reasonable approximation.
Quoted 18 lines
Quoted 18 lines
but the only warning that I see in this
function is the one complaining that RCU has been ignoring a request to start a grace period for too long. This usually happens because the RCU grace-period kthread (named "rcu_preempt" in your case, but can also be named "rcu_sched") is being prevented from running, but can be caused by other things as well.
Quoted 10 lines
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.0-rc3-next-20201110-00003-g920304642405-dirty #30
Hardware name: linux,dummy-virt (DT)
pstate: 20000085 (nzCv daIf -PAN -UAO -TCO BTYPE=--)
pc : rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
pc : rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711
lr : __xchg_mb arch/arm64/include/asm/cmpxchg.h:88 [inline]
lr : atomic_xchg include/asm-generic/atomic-instrumented.h:615 [inline]
lr : rcu_check_gp_start_stall kernel/rcu/tree_stall.h:751 [inline]
lr : rcu_check_gp_start_stall.isra.0+0x148/0x210 kernel/rcu/tree_stall.h:711
Quoted 6 lines
Quoted 1 line
Two program counters and four link registers? Awesome! ;-)
Ah I'm using syzkaller's symbolizer, which duplicates lines if there was an inline function (remove all the "[inline]" and it should make sense, but the "[inline]" tell you the actual line). Obviously for things like this it's a bit unintuitive. :-)
Very useful, though, and a big THANK YOU to those who made it happen!
Quoted 80 lines
Quoted 80 lines
Quoted 16 lines
sp : ffff800010003d20
x29: ffff800010003d20 x28: ffff274ac3a10000
x27: 0000000000000000 x26: ffff274b3dbe72d8
x25: ffffbcb867722000 x24: 0000000000000000
x23: 0000000000000000 x22: ffffbcb8681d1260
x21: ffffbcb86735b000 x20: ffffbcb867404440
x19: ffffbcb867404440 x18: 0000000000000123
x17: ffffbcb865d400f0 x16: 0000000000000002
x15: 0000000000000002 x14: 0000000000000000
x13: 003d090000000000 x12: 00001e8480000000
x11: ffffbcb867958980 x10: ffff800010003cf0
x9 : ffffbcb864f4b7c8 x8 : 0000000000000080
x7 : 0000000000000026 x6 : ffffbcb86774e4c0
x5 : 0000000000000000 x4 : 00000000d4001f4b
x3 : 0000000000000000 x2 : 0000000000000000
x1 : 0000000000000001 x0 : 0000000000000000
Quoted 5 lines
Call trace:
 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:750 [inline]
 rcu_check_gp_start_stall.isra.0+0x14c/0x210 kernel/rcu/tree_stall.h:711
 rcu_core+0x168/0x9e0 kernel/rcu/tree.c:2719
 rcu_core_si+0x18/0x28 kernel/rcu/tree.c:2737
The RCU_SOFTIRQ handler is causing this checking to occur, for whatever that is worth.
Quoted 38 lines
 __do_softirq+0x188/0x6b4 kernel/softirq.c:298
 do_softirq_own_stack include/linux/interrupt.h:568 [inline]
 invoke_softirq kernel/softirq.c:393 [inline]
 __irq_exit_rcu kernel/softirq.c:423 [inline]
 irq_exit+0x1cc/0x1e0 kernel/softirq.c:447
 __handle_domain_irq+0xb4/0x130 kernel/irq/irqdesc.c:690
 handle_domain_irq include/linux/irqdesc.h:170 [inline]
 gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
 el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
 arch_local_irq_restore+0x8/0x10 arch/arm64/include/asm/irqflags.h:124
 release_probes kernel/tracepoint.c:113 [inline]
 tracepoint_remove_func kernel/tracepoint.c:315 [inline]
 tracepoint_probe_unregister+0x220/0x378 kernel/tracepoint.c:382
 trace_event_reg+0x58/0x150 kernel/trace/trace_events.c:298
 __ftrace_event_enable_disable+0x424/0x608 kernel/trace/trace_events.c:412
 ftrace_event_enable_disable kernel/trace/trace_events.c:495 [inline]
 __ftrace_set_clr_event_nolock+0x120/0x180 kernel/trace/trace_events.c:811
 __ftrace_set_clr_event+0x60/0x90 kernel/trace/trace_events.c:833
 event_trace_self_tests+0xd4/0x114 kernel/trace/trace_events.c:3661
 event_trace_self_test_with_function kernel/trace/trace_events.c:3734 [inline]
 event_trace_self_tests_init+0x88/0xa8 kernel/trace/trace_events.c:3747
 do_one_initcall+0xa4/0x500 init/main.c:1212
 do_initcall_level init/main.c:1285 [inline]
 do_initcalls init/main.c:1301 [inline]
 do_basic_setup init/main.c:1321 [inline]
 kernel_init_freeable+0x344/0x3c4 init/main.c:1521
 kernel_init+0x20/0x16c init/main.c:1410
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:961
irq event stamp: 3274113
hardirqs last  enabled at (3274112): [<ffffbcb864f8aee4>] rcu_core+0x974/0x9e0 kernel/rcu/tree.c:2716
hardirqs last disabled at (3274113): [<ffffbcb866233bf0>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
hardirqs last disabled at (3274113): [<ffffbcb866233bf0>] _raw_spin_lock_irqsave+0xb8/0x14c kernel/locking/spinlock.c:159
softirqs last  enabled at (3272576): [<ffffbcb864e10b80>] __do_softirq+0x630/0x6b4 kernel/softirq.c:325
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] do_softirq_own_stack include/linux/interrupt.h:568 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] invoke_softirq kernel/softirq.c:393 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] __irq_exit_rcu kernel/softirq.c:423 [inline]
softirqs last disabled at (3274101): [<ffffbcb864ec6c54>] irq_exit+0x1cc/0x1e0 kernel/softirq.c:447
---[ end trace 902768efebf5a607 ]---
Quoted 1 line
rcu: rcu_preempt: wait state: RCU_GP_WAIT_GPS(1) ->state: 0x0 delta ->gp_activity 4452 ->gp_req_activity 3848 ->gp_wake_time 3848 ->gp_wake_seq 2696 ->gp_seq 2696 ->gp_seq_needed 2700 ->gp_flags 0x1
The last thing that RCU's grace-period kthread did was to go to sleep waiting for a grace-period request (RCU_GP_WAIT_GPS).
Quoted 9 lines
rcu: rcu_node 0:0 ->gp_seq 2696 ->gp_seq_needed 2700
rcu: RCU callbacks invoked since boot: 2583
rcu_tasks: RTGS_WAIT_CBS(11) since 567120 g:1 i:0/0 k.
rcu_tasks_rude: RTGS_WAIT_CBS(11) since 567155 g:1 i:0/1 k.
rcu_tasks_trace: RTGS_INIT(0) since 4295464549 g:0 i:0/0 k. N0 h:0/0/0
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=3752 jiffies, g=2705, q=8)
rcu: All QSes seen, last rcu_preempt kthread activity 557 (4295471128-4295470571), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 557 jiffies! g2705 f0x2 RCU_GP_CLEANUP(7) ->state=0x0 ->cpu=0
And here we see that RCU's grace-period kthread has in fact been starved.
Quoted 8 lines
Quoted 5 lines
This kthread is now in RCU_GP_CLEANUP, perhaps because of the wakeup that is sent in rcu_check_gp_kthread_starvation().
My current guess is that this is a consequence of the earlier failures, but who knows?
I can try bisection again, or reverting some commits that might be suspicious? But we'd need some selection of suspicious commits.

Quoted 7 lines

The report claims that one of the rcu_node ->lock fields is held with interrupts enabled, which would indeed be bad. Except that all of the stack traces that it shows have these locks held within the scheduling-clock interrupt handler. Now with the "rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled" but without the "sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled" commit, I understand why. With both, I don't see how this happens.

I'm at a loss, but happy to keep bisecting and trying patches. I'm also considering:

Is it the compiler? Probably not, I tried 2 versions of GCC.

Can we trust lockdep to precisely know IRQ state? I know there's been some recent work around this, but hopefully we're not affected here?

Is QEMU buggy?

Quoted 6 lines

At this point, I am reduced to adding lockdep_assert_irqs_disabled() calls at various points in that code, as shown in the patch below.
At this point, I would guess that your first priority would be the initial bug rather than this following issue, but you never know, this might well help diagnose the initial bug.

I don't mind either way. I'm worried deadlocking the whole system might be worse.

Quoted 9 lines

Thanx, Paul
------------------------------------------------------------------------
commit ccedf00693ef60f7c06d23490fc41bb60dd43dc3
Author: Paul E. McKenney <[email protected]>
Date:   Thu Nov 19 10:13:06 2020 -0800
rcu: Add lockdep_assert_irqs_disabled() to rcu_sched_clock_irq() and callees

Applied that. See new log attached -- I don't see any of them have fired.

I also upgraded to next-20201119 -- nothing has changed though, and the warnings and deadlocks still appear.

Thanks,
-- Marco

Testing all events: OK
Running tests again, along with the function tracer Running tests on all trace events:
Testing all events:
hrtimer: interrupt took 11213232 ns

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 11s!

Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 13s!

Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_shepherd

BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!

BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 11s!

BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 21s!

Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
in-flight: 15:vmstat_shepherd
workqueue events_power_efficient: flags=0x82
pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3
pending: neigh_periodic_work
pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=8s workers=2 idle: 5

BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 34s!

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=3752 jiffies, g=2365, q=2)

rcu: All QSes seen, last rcu_preempt kthread activity 2599 (4295010564-4295007965), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 2599 jiffies! g2365 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack: 0 pid: 10 ppid: 2 flags:0x00000428

Call trace:
 __switch_to+0x148/0x1f0 arch/arm64/kernel/process.c:577
 context_switch kernel/sched/core.c:4268 [inline]
 __schedule+0x2dc/0x9a8 kernel/sched/core.c:5018
 preempt_schedule_notrace+0x70/0x1c0 kernel/sched/core.c:5251
 __ftrace_ops_list_func kernel/trace/ftrace.c:6955 [inline]
 ftrace_ops_list_func+0x10c/0x218 kernel/trace/ftrace.c:6976
 ftrace_graph_call+0x0/0x4
 preempt_count_add+0x8/0x1a0 arch/arm64/include/asm/atomic.h:65
 schedule+0x44/0x100 kernel/sched/core.c:5096
 schedule_timeout+0x240/0x538 kernel/time/timer.c:1871
 rcu_gp_fqs_loop kernel/rcu/tree.c:1946 [inline]
 rcu_gp_kthread+0x618/0x1bd8 kernel/rcu/tree.c:2119
 kthread+0x13c/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:963
rcu: Stack dump where RCU GP kthread last ran:
Task dump for CPU 0:
task:khungtaskd      state:R  running task     stack:    0 pid:   23 ppid:     2 flags:0x0000042a
Call trace:
 dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
 sched_show_task kernel/sched/core.c:6947 [inline]
 sched_show_task+0x208/0x230 kernel/sched/core.c:6921
 dump_cpu_task+0x4c/0x5c kernel/sched/core.c:8985
 rcu_check_gp_kthread_starvation+0x240/0x388 kernel/rcu/tree_stall.h:482
 print_other_cpu_stall kernel/rcu/tree_stall.h:556 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:679 [inline]
 rcu_pending kernel/rcu/tree.c:3764 [inline]
 rcu_sched_clock_irq+0x131c/0x1408 kernel/rcu/tree.c:2588
 update_process_times+0x6c/0xb8 kernel/time/timer.c:1709
 tick_sched_handle.isra.0+0x58/0x88 kernel/time/tick-sched.c:176
 tick_sched_timer+0x68/0xe0 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
 __hrtimer_run_queues+0x288/0x730 kernel/time/hrtimer.c:1583
 hrtimer_interrupt+0x114/0x288 kernel/time/hrtimer.c:1645
 timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline]
 arch_timer_handler_virt+0x50/0x70 drivers/clocksource/arm_arch_timer.c:658
 handle_percpu_devid_irq+0x104/0x4c0 kernel/irq/chip.c:930
 generic_handle_irq_desc include/linux/irqdesc.h:152 [inline]
 generic_handle_irq+0x54/0x78 kernel/irq/irqdesc.c:650
 __handle_domain_irq+0xac/0x130 kernel/irq/irqdesc.c:687
 handle_domain_irq include/linux/irqdesc.h:170 [inline]
 gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
 el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
 arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline]
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline]
 _raw_spin_unlock_irq+0x50/0x98 kernel/locking/spinlock.c:199
 finish_lock_switch kernel/sched/core.c:4046 [inline]
 finish_task_switch+0xb4/0x398 kernel/sched/core.c:4146
 context_switch kernel/sched/core.c:4271 [inline]
 __schedule+0x2e0/0x9a8 kernel/sched/core.c:5018
 preempt_schedule_irq+0x4c/0xa0 kernel/sched/core.c:5280
 arm64_preempt_schedule_irq+0xd0/0x118 arch/arm64/kernel/process.c:725
 el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:664
 check_hung_uninterruptible_tasks kernel/hung_task.c:231 [inline]
 watchdog+0x5d8/0xbe8 kernel/hung_task.c:338
 kthread+0x13c/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:963

================================
WARNING: inconsistent lock state
5.10.0-rc4-next-20201119-00003-gb88cbc8d31ee #4 Not tainted
--------------------------------
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
khungtaskd/23 [HC0[0]:SC0[0]:HE0:SE1] takes:
ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:516 [inline] ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:679 [inline] ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3764 [inline] ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x7c8/0x1408 kernel/rcu/tree.c:2588 {IN-HARDIRQ-W} state was registered at:

  mark_lock kernel/locking/lockdep.c:4373 [inline]
  mark_usage kernel/locking/lockdep.c:4301 [inline]
  __lock_acquire+0xae8/0x1ac8 kernel/locking/lockdep.c:4784
  lock_acquire kernel/locking/lockdep.c:5435 [inline]
  lock_acquire+0x268/0x508 kernel/locking/lockdep.c:5400
  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
  _raw_spin_lock_irqsave+0x78/0x14c kernel/locking/spinlock.c:159
  print_other_cpu_stall kernel/rcu/tree_stall.h:516 [inline]
  check_cpu_stall kernel/rcu/tree_stall.h:679 [inline]
  rcu_pending kernel/rcu/tree.c:3764 [inline]
  rcu_sched_clock_irq+0x7c8/0x1408 kernel/rcu/tree.c:2588
  update_process_times+0x6c/0xb8 kernel/time/timer.c:1709
  tick_sched_handle.isra.0+0x58/0x88 kernel/time/tick-sched.c:176
  tick_sched_timer+0x68/0xe0 kernel/time/tick-sched.c:1328
  __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
  __hrtimer_run_queues+0x288/0x730 kernel/time/hrtimer.c:1583
  hrtimer_interrupt+0x114/0x288 kernel/time/hrtimer.c:1645
  timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline]
  arch_timer_handler_virt+0x50/0x70 drivers/clocksource/arm_arch_timer.c:658
  handle_percpu_devid_irq+0x104/0x4c0 kernel/irq/chip.c:930
  generic_handle_irq_desc include/linux/irqdesc.h:152 [inline]
  generic_handle_irq+0x54/0x78 kernel/irq/irqdesc.c:650
  __handle_domain_irq+0xac/0x130 kernel/irq/irqdesc.c:687
  handle_domain_irq include/linux/irqdesc.h:170 [inline]
  gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370
  el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651
  arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline]
  __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline]
  _raw_spin_unlock_irq+0x50/0x98 kernel/locking/spinlock.c:199
  finish_lock_switch kernel/sched/core.c:4046 [inline]
  finish_task_switch+0xb4/0x398 kernel/sched/core.c:4146
  context_switch kernel/sched/core.c:4271 [inline]
  __schedule+0x2e0/0x9a8 kernel/sched/core.c:5018
  preempt_schedule_irq+0x4c/0xa0 kernel/sched/core.c:5280
  arm64_preempt_schedule_irq+0xd0/0x118 arch/arm64/kernel/process.c:725
  el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:664
  check_hung_uninterruptible_tasks kernel/hung_task.c:231 [inline]
  watchdog+0x5d8/0xbe8 kernel/hung_task.c:338
  kthread+0x13c/0x188 kernel/kthread.c:292
  ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:963
irq event stamp: 15198
hardirqs last  enabled at (15197): [<ffffd1f05041241c>] el1_irq+0xdc/0x180 arch/arm64/kernel/entry.S:685
hardirqs last disabled at (15198): [<ffffd1f0504123c0>] el1_irq+0x80/0x180 arch/arm64/kernel/entry.S:648
softirqs last  enabled at (14846): [<ffffd1f050410b80>] __do_softirq+0x630/0x6b4 kernel/softirq.c:325
softirqs last disabled at (14843): [<ffffd1f0504c623c>] do_softirq_own_stack include/linux/interrupt.h:568 [inline]
softirqs last disabled at (14843): [<ffffd1f0504c623c>] invoke_softirq kernel/softirq.c:393 [inline]
softirqs last disabled at (14843): [<ffffd1f0504c623c>] __irq_exit_rcu kernel/softirq.c:423 [inline]
softirqs last disabled at (14843): [<ffffd1f0504c623c>] irq_exit+0x1cc/0x1e0 kernel/softirq.c:447

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0
       ----
  lock(rcu_node_0);
  <Interrupt>
    lock(rcu_node_0);

*** DEADLOCK ***

2 locks held by khungtaskd/23:
#0: ffffd1f0529f1420 (rcu_read_lock){....}-{1:2}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:226 [inline] #0: ffffd1f0529f1420 (rcu_read_lock){....}-{1:2}, at: watchdog+0x15c/0xbe8 kernel/hung_task.c:338 #1: ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:516 [inline] #1: ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:679 [inline] #1: ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3764 [inline]
#1: ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x7c8/0x1408 kernel/rcu/tree.c:2588

stack backtrace:
CPU: 0 PID: 23 Comm: khungtaskd Not tainted 5.10.0-rc4-next-20201119-00003-gb88cbc8d31ee #4
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x140/0x1bc lib/dump_stack.c:120
 print_usage_bug kernel/locking/lockdep.c:3738 [inline]
 print_usage_bug+0x2a0/0x2f0 kernel/locking/lockdep.c:3705
 valid_state kernel/locking/lockdep.c:3749 [inline]
 mark_lock_irq kernel/locking/lockdep.c:3952 [inline]
 mark_lock.part.0+0x438/0x4e8 kernel/locking/lockdep.c:4409
 mark_lock kernel/locking/lockdep.c:4007 [inline]
 mark_held_locks+0x54/0x90 kernel/locking/lockdep.c:4010
 __trace_hardirqs_on_caller kernel/locking/lockdep.c:4028 [inline]
 lockdep_hardirqs_on_prepare+0xe0/0x290 kernel/locking/lockdep.c:4096
 trace_hardirqs_on+0x90/0x370 kernel/trace/trace_preemptirq.c:49
 el1_irq+0xdc/0x180 arch/arm64/kernel/entry.S:685
 arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline]
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline]
 _raw_spin_unlock_irq+0x50/0x98 kernel/locking/spinlock.c:199
 finish_lock_switch kernel/sched/core.c:4046 [inline]
 finish_task_switch+0xb4/0x398 kernel/sched/core.c:4146
 context_switch kernel/sched/core.c:4271 [inline]
 __schedule+0x2e0/0x9a8 kernel/sched/core.c:5018
 preempt_schedule_irq+0x4c/0xa0 kernel/sched/core.c:5280
 arm64_preempt_schedule_irq+0xd0/0x118 arch/arm64/kernel/process.c:725
 el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:664
 check_hung_uninterruptible_tasks kernel/hung_task.c:231 [inline]
 watchdog+0x5d8/0xbe8 kernel/hung_task.c:338
 kthread+0x13c/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:963
BUG: scheduling while atomic: khungtaskd/23/0x00000002
INFO: lockdep is turned off.
Modules linked in:
Preemption disabled at:
[<ffffd1f05181ce7c>] preempt_schedule_irq+0x3c/0xa0 kernel/sched/core.c:5278
CPU: 0 PID: 23 Comm: khungtaskd Not tainted 5.10.0-rc4-next-20201119-00003-gb88cbc8d31ee #4
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x140/0x1bc lib/dump_stack.c:120
 __schedule_bug+0xcc/0xe0 kernel/sched/core.c:4757
 schedule_debug kernel/sched/core.c:4784 [inline]
 __schedule+0x888/0x9a8 kernel/sched/core.c:4912
 preempt_schedule_irq+0x4c/0xa0 kernel/sched/core.c:5280
 arm64_preempt_schedule_irq+0xd0/0x118 arch/arm64/kernel/process.c:725
 el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:664
 check_hung_uninterruptible_tasks kernel/hung_task.c:231 [inline]
 watchdog+0x5d8/0xbe8 kernel/hung_task.c:338
 kthread+0x13c/0x188 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:963

Paul E. McKenney

maintainer

2020-11-19 21:35 UTC #29 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 2 lines · Marco Elver

Quoted 1 line · Paul E. McKenney
On Thu, Nov 19, 2020 at 06:02:59PM +0100, Marco Elver wrote:

[ . . . ]

Quoted 25 lines

Quoted 10 lines
Quoted 2 lines
I can try bisection again, or reverting some commits that might be suspicious? But we'd need some selection of suspicious commits.
The report claims that one of the rcu_node ->lock fields is held with interrupts enabled, which would indeed be bad. Except that all of the stack traces that it shows have these locks held within the scheduling-clock interrupt handler. Now with the "rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled" but without the "sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled" commit, I understand why. With both, I don't see how this happens.
I'm at a loss, but happy to keep bisecting and trying patches. I'm also considering:
Is it the compiler? Probably not, I tried 2 versions of GCC.
Can we trust lockdep to precisely know IRQ state? I know there's been some recent work around this, but hopefully we're not affected here?
Is QEMU buggy?
Quoted 3 lines
At this point, I am reduced to adding lockdep_assert_irqs_disabled() calls at various points in that code, as shown in the patch below.

Quoted 6 lines

Quoted 3 lines
At this point, I would guess that your first priority would be the initial bug rather than this following issue, but you never know, this might well help diagnose the initial bug.
I don't mind either way. I'm worried deadlocking the whole system might be worse.

Here is another set of lockdep_assert_irqs_disabled() calls on the off-chance that they actually find something.

Thanx, Paul

------------------------------------------------------------------------

commit bcca5277df3f24db15e15ccc8b05ecf346d05169

Author: Paul E. McKenney <[email protected]>
Date:   Thu Nov 19 13:30:33 2020 -0800

rcu: Add lockdep_assert_irqs_disabled() to raw_spin_unlock_rcu_node() macros

This commit adds a lockdep_assert_irqs_disabled() call to the helper macros that release the rcu_node structure's ->lock, namely to raw_spin_unlock_rcu_node(), raw_spin_unlock_irq_rcu_node() and raw_spin_unlock_irqrestore_rcu_node(). The point of this is to help track down a situation where lockdep appears to be insisting that interrupts are enabled while holding an rcu_node structure's ->lock.

Link https://lore.kernel.org/lkml/[email protected]/ open here

Signed-off-by Paul E. McKenney <[email protected]>

kernel/rcu/rcu.h +13 -3

index 59ef1ae..bf0827d 100644
@@ -378,7 +378,11 @@ do {									\
 	smp_mb__after_unlock_lock();					\
 } while (0)
 
-#define raw_spin_unlock_rcu_node(p) raw_spin_unlock(&ACCESS_PRIVATE(p, lock))
+#define raw_spin_unlock_rcu_node(p)					\
+do {									\
+	lockdep_assert_irqs_disabled();					\
+	raw_spin_unlock(&ACCESS_PRIVATE(p, lock));			\
+} while (0)
 
 #define raw_spin_lock_irq_rcu_node(p)					\
 do {									\

@@ -387,7 +391,10 @@ do {									\
 } while (0)
 
 #define raw_spin_unlock_irq_rcu_node(p)					\
-	raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock))
+do {									\
+	lockdep_assert_irqs_disabled();					\
+	raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock));			\
+} while (0)
 
 #define raw_spin_lock_irqsave_rcu_node(p, flags)			\
 do {									\

@@ -396,7 +403,10 @@ do {									\
 } while (0)
 
 #define raw_spin_unlock_irqrestore_rcu_node(p, flags)			\
-	raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags)
+do {									\
+	lockdep_assert_irqs_disabled();					\
+	raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags);	\
+} while (0)
 
 #define raw_spin_trylock_rcu_node(p)					\
 ({									\

Will Deacon

2020-11-19 22:54 UTC #30 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 35 lines · Paul E. McKenney

Quoted 2 lines · Marco Elver
Quoted 1 line · Paul E. McKenney
On Thu, Nov 19, 2020 at 06:02:59PM +0100, Marco Elver wrote:
[ . . . ]
Quoted 29 lines
Quoted 10 lines
Quoted 2 lines
I can try bisection again, or reverting some commits that might be suspicious? But we'd need some selection of suspicious commits.
The report claims that one of the rcu_node ->lock fields is held with interrupts enabled, which would indeed be bad. Except that all of the stack traces that it shows have these locks held within the scheduling-clock interrupt handler. Now with the "rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled" but without the "sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled" commit, I understand why. With both, I don't see how this happens.
I'm at a loss, but happy to keep bisecting and trying patches. I'm also considering:
Is it the compiler? Probably not, I tried 2 versions of GCC.
Can we trust lockdep to precisely know IRQ state? I know there's been some recent work around this, but hopefully we're not affected here?
Is QEMU buggy?
Quoted 6 lines
At this point, I am reduced to adding lockdep_assert_irqs_disabled() calls at various points in that code, as shown in the patch below.
At this point, I would guess that your first priority would be the initial bug rather than this following issue, but you never know, this might well help diagnose the initial bug.

Quoted 5 lines

Quoted 2 lines
I don't mind either way. I'm worried deadlocking the whole system might be worse.
Here is another set of lockdep_assert_irqs_disabled() calls on the off-chance that they actually find something.

FWIW, arm64 is known broken wrt lockdep and irq tracing atm. Mark has been looking at that and I think he is close to having something workable.

Mark -- is there anything Marco and Paul can try out?

Will

Mark Rutland

2020-11-20 10:30 UTC #31 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 39 lines · Will Deacon

Quoted 38 lines · Paul E. McKenney
Quoted 2 lines · Marco Elver
Quoted 1 line · Paul E. McKenney
On Thu, Nov 19, 2020 at 06:02:59PM +0100, Marco Elver wrote:
[ . . . ]
Quoted 31 lines
Quoted 10 lines
Quoted 2 lines
I can try bisection again, or reverting some commits that might be suspicious? But we'd need some selection of suspicious commits.
The report claims that one of the rcu_node ->lock fields is held with interrupts enabled, which would indeed be bad. Except that all of the stack traces that it shows have these locks held within the scheduling-clock interrupt handler. Now with the "rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled" but without the "sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled" commit, I understand why. With both, I don't see how this happens.
I'm at a loss, but happy to keep bisecting and trying patches. I'm also considering:
Is it the compiler? Probably not, I tried 2 versions of GCC.
Can we trust lockdep to precisely know IRQ state? I know there's been some recent work around this, but hopefully we're not affected here?
Is QEMU buggy?
Quoted 6 lines
At this point, I am reduced to adding lockdep_assert_irqs_disabled() calls at various points in that code, as shown in the patch below.
At this point, I would guess that your first priority would be the initial bug rather than this following issue, but you never know, this might well help diagnose the initial bug.
I don't mind either way. I'm worried deadlocking the whole system might be worse.

Quoted 7 lines

Quoted 2 lines
Here is another set of lockdep_assert_irqs_disabled() calls on the off-chance that they actually find something.
FWIW, arm64 is known broken wrt lockdep and irq tracing atm. Mark has been looking at that and I think he is close to having something workable.
Mark -- is there anything Marco and Paul can try out?

I initially traced some issues back to commit:

044d0d6de9f50192 ("lockdep: Only trace IRQ edges")

... and that change of semantic could cause us to miss edges in some cases, but IIUC mostly where we haven't done the right thing in exception entry/return.

I don't think my patches address this case yet, but my WIP (currently just fixing user<->kernel transitions) is at:

https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/irq-fixes

I'm looking into the kernel<->kernel transitions now, and I know that we mess up RCU management for a small window around arch_cpu_idle, but it's not immediately clear to me if either of those cases could cause this report.

Thanks,
Mark.

Marco Elver

author maintainer

2020-11-20 14:03 UTC #32 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 59 lines · Mark Rutland

Quoted 39 lines · Will Deacon
Quoted 38 lines · Paul E. McKenney
Quoted 2 lines · Marco Elver
Quoted 1 line · Paul E. McKenney
On Thu, Nov 19, 2020 at 06:02:59PM +0100, Marco Elver wrote:
[ . . . ]
Quoted 31 lines
Quoted 10 lines
Quoted 2 lines
I can try bisection again, or reverting some commits that might be suspicious? But we'd need some selection of suspicious commits.
The report claims that one of the rcu_node ->lock fields is held with interrupts enabled, which would indeed be bad. Except that all of the stack traces that it shows have these locks held within the scheduling-clock interrupt handler. Now with the "rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled" but without the "sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled" commit, I understand why. With both, I don't see how this happens.
I'm at a loss, but happy to keep bisecting and trying patches. I'm also considering:
Is it the compiler? Probably not, I tried 2 versions of GCC.
Can we trust lockdep to precisely know IRQ state? I know there's been some recent work around this, but hopefully we're not affected here?
Is QEMU buggy?
Quoted 6 lines
At this point, I am reduced to adding lockdep_assert_irqs_disabled() calls at various points in that code, as shown in the patch below.
At this point, I would guess that your first priority would be the initial bug rather than this following issue, but you never know, this might well help diagnose the initial bug.
I don't mind either way. I'm worried deadlocking the whole system might be worse.
Quoted 7 lines
Quoted 2 lines
Here is another set of lockdep_assert_irqs_disabled() calls on the off-chance that they actually find something.
FWIW, arm64 is known broken wrt lockdep and irq tracing atm. Mark has been looking at that and I think he is close to having something workable.
Mark -- is there anything Marco and Paul can try out?
I initially traced some issues back to commit:
044d0d6de9f50192 ("lockdep: Only trace IRQ edges")
... and that change of semantic could cause us to miss edges in some cases, but IIUC mostly where we haven't done the right thing in exception entry/return.
I don't think my patches address this case yet, but my WIP (currently just fixing user<->kernel transitions) is at:

Quoted 6 lines

https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/irq-fixes
I'm looking into the kernel<->kernel transitions now, and I know that we mess up RCU management for a small window around arch_cpu_idle, but it's not immediately clear to me if either of those cases could cause this report.

Thank you -- I tried your irq-fixes, however that didn't seem to fix the problem (still get warnings and then a panic). :-/

| [  118.375217] Testing all events: OK
| [  174.878839] Running tests again, along with the function tracer
| [  174.894781] Running tests on all trace events:
| [  174.906734] Testing all events: 
| [  176.204533] hrtimer: interrupt took 9035008 ns
| [  286.788330] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s!
| [  286.883216] Showing busy workqueues and worker pools:
| [  286.899647] workqueue events: flags=0x0
| [  286.920606]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
| [  286.933010]     pending: vmstat_shepherd
| [  644.323445] INFO: task kworker/u2:1:107 blocked for more than 12 seconds.
| [  649.448126]       Not tainted 5.10.0-rc4-next-20201119-00004-g77838ee21ff6-dirty #17
| [  656.619598] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
| [  660.623500] task:kworker/u2:1    state:R stack:    0 pid:  107 ppid:     2 flags:0x00000428
| [  671.587980] Call trace:
| [  674.885884]  __switch_to+0x148/0x1f0
| [  675.267490]  __schedule+0x2dc/0x9a8
| [  677.748050]  schedule+0x4c/0x100
| [  679.223880]  worker_thread+0xe8/0x510
| [  680.663844]  kthread+0x13c/0x188
| [  681.663992]  ret_from_fork+0x10/0x34
| [  684.493389] 
| [  684.493389] Showing all locks held in the system:
| [  688.554449] 4 locks held by swapper/0/1:
| [  691.747079] 1 lock held by khungtaskd/23:
| [  692.525727]  #0: ffffa1ebd7ff1420 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x34/0x198
| [  704.403177] 
| [  704.630928] =============================================
| [  704.630928] 
| [  706.168072] Kernel panic - not syncing: hung_task: blocked tasks
| [  706.172894] CPU: 0 PID: 23 Comm: khungtaskd Not tainted 5.10.0-rc4-next-20201119-00004-g77838ee21ff6-dirty #17
| [  706.178507] Hardware name: linux,dummy-virt (DT)
| [  706.182658] Call trace:
| [  706.186231]  dump_backtrace+0x0/0x240
| [  706.190124]  show_stack+0x34/0x88
| [  706.193917]  dump_stack+0x140/0x1bc
| [  706.197728]  panic+0x1e4/0x494
| [  706.201440]  watchdog+0x668/0xbe8
| [  706.205238]  kthread+0x13c/0x188
| [  706.208991]  ret_from_fork+0x10/0x34
| [  706.214532] Kernel Offset: 0x21ebc5a00000 from 0xffff800010000000
| [  706.219014] PHYS_OFFSET: 0xffffad8a80000000
| [  706.223148] CPU features: 0x0240022,61806082
| [  706.227149] Memory Limit: none
| [  706.233359] ---[ end Kernel panic - not syncing: hung_task: blocked tasks ]---

Thanks,
-- Marco

Mark Rutland

2020-11-23 19:32 UTC #33 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 20 lines · Marco Elver

Quoted 19 lines · Mark Rutland
Quoted 4 lines · Will Deacon
FWIW, arm64 is known broken wrt lockdep and irq tracing atm. Mark has been looking at that and I think he is close to having something workable.
Mark -- is there anything Marco and Paul can try out?
I initially traced some issues back to commit:
044d0d6de9f50192 ("lockdep: Only trace IRQ edges")
... and that change of semantic could cause us to miss edges in some cases, but IIUC mostly where we haven't done the right thing in exception entry/return.
I don't think my patches address this case yet, but my WIP (currently just fixing user<->kernel transitions) is at:
https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/irq-fixes

Quoted 7 lines

Quoted 4 lines
I'm looking into the kernel<->kernel transitions now, and I know that we mess up RCU management for a small window around arch_cpu_idle, but it's not immediately clear to me if either of those cases could cause this report.
Thank you -- I tried your irq-fixes, however that didn't seem to fix the problem (still get warnings and then a panic). :-/

I've just updated that branch with a new version which I hope covers kernel<->kernel transitions too. If you get a chance, would you mind giving that a spin?

The HEAD commit should be:

a51334f033f8ee88 ("HACK: check IRQ tracing has RCU watching")

Otherwise, I intend to clean that up and post it tomorrow (without the additional debug hacks). I've thrown my local Syzkaller instance at it in the mean time (and if I get the chance tomrrow I'll try to get rcutorture setup), and the only report I'm seeing so far looks genuine:

| BUG: sleeping function called from invalid context in sta_info_move_state

... as that was reported on x86 too, per:

https://syzkaller.appspot.com/bug?id=6c7899acf008be2ddcddb46a2567c2153193632a

Thanks,
Mark.

Marco Elver

author maintainer

2020-11-24 14:03 UTC #34 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 29 lines · Mark Rutland

Quoted 20 lines · Marco Elver
Quoted 19 lines · Mark Rutland
Quoted 4 lines · Will Deacon
FWIW, arm64 is known broken wrt lockdep and irq tracing atm. Mark has been looking at that and I think he is close to having something workable.
Mark -- is there anything Marco and Paul can try out?
I initially traced some issues back to commit:
044d0d6de9f50192 ("lockdep: Only trace IRQ edges")
... and that change of semantic could cause us to miss edges in some cases, but IIUC mostly where we haven't done the right thing in exception entry/return.
I don't think my patches address this case yet, but my WIP (currently just fixing user<->kernel transitions) is at:
https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/irq-fixes
Quoted 7 lines
Quoted 4 lines
I'm looking into the kernel<->kernel transitions now, and I know that we mess up RCU management for a small window around arch_cpu_idle, but it's not immediately clear to me if either of those cases could cause this report.
Thank you -- I tried your irq-fixes, however that didn't seem to fix the problem (still get warnings and then a panic). :-/

Quoted 7 lines

I've just updated that branch with a new version which I hope covers kernel<->kernel transitions too. If you get a chance, would you mind giving that a spin?
The HEAD commit should be:
a51334f033f8ee88 ("HACK: check IRQ tracing has RCU watching")

Thank you! Your series appears to work and fixes the stalls and deadlocks (3 trials)! I noticed there are a bunch of warnings in the log that might be relevant (see attached).

Note, I also reverted

sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled

and that still works.

Thanks,
-- Marco

Quoted 5 lines

Otherwise, I intend to clean that up and post it tomorrow (without the additional debug hacks). I've thrown my local Syzkaller instance at it in the mean time (and if I get the chance tomrrow I'll try to get rcutorture setup), and the only report I'm seeing so far looks genuine:

Quoted 8 lines

| BUG: sleeping function called from invalid context in sta_info_move_state
... as that was reported on x86 too, per:
https://syzkaller.appspot.com/bug?id=6c7899acf008be2ddcddb46a2567c2153193632a
Thanks,
Mark.

[    0.000000] Booting Linux on physical CPU 0x0000000000 [0x411fd070]
[    0.000000] Linux version 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 ([email protected]) (aarch64-none-linux-gnu-gcc (GNU Toolchain for the A-profile Architecture 9.2-2019.12 (arm-9.10)) 9.2.1 20191025, GNU ld (GNU Toolchain for the A-profile Architecture 9.2-2019.12 (arm-9.10)) 2.33.1.20191209) #25 SMP PREEMPT Tue Nov 24 13:47:30 CET 2020
[    0.000000] Machine model: linux,dummy-virt
[    0.000000] efi: UEFI not found.
[    0.000000] cma: Reserved 32 MiB at 0x00000000be000000
[    0.000000] earlycon: pl11 at MMIO 0x0000000009000000 (options '')
[    0.000000] printk: bootconsole [pl11] enabled
[    0.000000] NUMA: No NUMA configuration found
[    0.000000] NUMA: Faking a node at [mem 0x0000000040000000-0x00000000bfffffff]
[    0.000000] NUMA: NODE_DATA [mem 0xbdbf6000-0xbdbf7fff]
[    0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x0000000040000000-0x000000007fffffff]
[    0.000000]   DMA32    [mem 0x0000000080000000-0x00000000bfffffff]
[    0.000000]   Normal   empty
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000040000000-0x00000000bfffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000040000000-0x00000000bfffffff]
[    0.000000] On node 0 totalpages: 524288
[    0.000000]   DMA zone: 4096 pages used for memmap
[    0.000000]   DMA zone: 0 pages reserved
[    0.000000]   DMA zone: 262144 pages, LIFO batch:63
[    0.000000]   DMA32 zone: 4096 pages used for memmap
[    0.000000]   DMA32 zone: 262144 pages, LIFO batch:63
[    0.000000] psci: probing for conduit method from DT.
[    0.000000] psci: PSCIv0.2 detected in firmware.
[    0.000000] psci: Using standard PSCI v0.2 function IDs
[    0.000000] psci: Trusted OS migration not required
[    0.000000] percpu: Embedded 49 pages/cpu s162704 r8192 d29808 u200704
[    0.000000] pcpu-alloc: s162704 r8192 d29808 u200704 alloc=49*4096
[    0.000000] pcpu-alloc: [0] 0 
[    0.000000] Detected PIPT I-cache on CPU0
[    0.000000] CPU features: detected: ARM erratum 832075
[    0.000000] CPU features: detected: ARM erratum 834220
[    0.000000] CPU features: detected: EL2 vector hardening
[    0.000000] CPU features: kernel page table isolation forced ON by KASLR
[    0.000000] CPU features: detected: Kernel page table isolation (KPTI)
[    0.000000] CPU features: detected: Spectre-v2
[    0.000000] CPU features: detected: Spectre-v4
[    0.000000] CPU features: detected: ARM errata 1165522, 1319367, or 1530923
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 516096
[    0.000000] Policy zone: DMA32
[    0.000000] Kernel command line: console=ttyAMA0 root=/dev/sda debug earlycon earlyprintk=serial slub_debug=UZ slub_debug=- workqueue.watchdog_thresh=10
[    0.000000] Dentry cache hash table entries: 262144 (order: 9, 2097152 bytes, linear)
[    0.000000] Inode-cache hash table entries: 131072 (order: 8, 1048576 bytes, linear)
[    0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
[    0.000000] software IO TLB: mapped [mem 0x000000007bfff000-0x000000007ffff000] (64MB)
[    0.000000] Memory: 1903696K/2097152K available (20800K kernel code, 4024K rwdata, 8508K rodata, 8896K init, 11238K bss, 160688K reserved, 32768K cma-reserved)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[    0.000000] ftrace: allocating 56178 entries in 220 pages
[    0.000000] ftrace: allocated 220 pages with 5 groups
[    0.000000] Running RCU self tests
[    0.000000] rcu: Preemptible hierarchical RCU implementation.
[    0.000000] rcu: 	RCU event tracing is enabled.
[    0.000000] rcu: 	RCU lockdep checking is enabled.
[    0.000000] rcu: 	RCU restricting CPUs from NR_CPUS=256 to nr_cpu_ids=1.
[    0.000000] 	Trampoline variant of Tasks RCU enabled.
[    0.000000] 	Rude variant of Tasks RCU enabled.
[    0.000000] 	Tracing variant of Tasks RCU enabled.
[    0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 25 jiffies.
[    0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=1
[    0.000000] NR_IRQS: 64, nr_irqs: 64, preallocated irqs: 0
[    0.000000] GICv2m: range[mem 0x08020000-0x08020fff], SPI[80:143]
[    0.000000] random: get_random_bytes called from start_kernel+0x468/0x670 with crng_init=0
[    0.000000] arch_timer: cp15 timer(s) running at 62.50MHz (virt).
[    0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x1cd42e208c, max_idle_ns: 881590405314 ns
[    0.000291] sched_clock: 56 bits at 62MHz, resolution 16ns, wraps every 4398046511096ns
[    0.014280] Console: colour dummy device 80x25
[    0.015796] Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar
[    0.016131] ... MAX_LOCKDEP_SUBCLASSES:  8
[    0.016378] ... MAX_LOCK_DEPTH:          48
[    0.016626] ... MAX_LOCKDEP_KEYS:        8192
[    0.016887] ... CLASSHASH_SIZE:          4096
[    0.017138] ... MAX_LOCKDEP_ENTRIES:     32768
[    0.017385] ... MAX_LOCKDEP_CHAINS:      65536
[    0.017633] ... CHAINHASH_SIZE:          32768
[    0.017884]  memory used by lock dependency info: 6365 kB
[    0.018144]  memory used for stack traces: 4224 kB
[    0.018400]  per task-struct memory footprint: 1920 bytes
[    0.021247] Calibrating delay loop (skipped), value calculated using timer frequency.. 125.00 BogoMIPS (lpj=250000)
[    0.021914] pid_max: default: 32768 minimum: 301
[    0.025132] LSM: Security Framework initializing
[    0.027343] Mount-cache hash table entries: 4096 (order: 3, 32768 bytes, linear)
[    0.028580] Mountpoint-cache hash table entries: 4096 (order: 3, 32768 bytes, linear)
[    0.115959] rcu: Hierarchical SRCU implementation.
[    0.135096] EFI services will not be available.
[    0.139828] smp: Bringing up secondary CPUs ...
[    0.140267] smp: Brought up 1 node, 1 CPU
[    0.140587] SMP: Total of 1 processors activated.
[    0.141037] CPU features: detected: 32-bit EL0 Support
[    0.141769] CPU features: detected: CRC32 instructions
[    0.142144] CPU features: detected: 32-bit EL1 Support
[    0.547379] CPU: All CPU(s) started at EL1
[    0.548418] alternatives: patching kernel code
[    0.606936] devtmpfs: initialized
[    0.679006] KASLR enabled
[    0.707823] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns
[    0.708867] futex hash table entries: 256 (order: 3, 32768 bytes, linear)
[    0.710674] Running postponed tracer tests:
[    0.714449] Testing tracer function: PASSED
[    8.629279] Testing dynamic ftrace: PASSED
[    9.591794] Testing dynamic ftrace ops #1: 
[   12.266300] (1 0 1 0 0) 
[   12.266797] (1 1 2 0 0) 
[   20.579408] (2 1 3 0 1141111) 
[   20.582238] (2 2 4 0 1141539) PASSED
[   24.613636] Testing dynamic ftrace ops #2: 
[   34.951883] (1 0 1 1116153 0) 
[   34.954384] (1 1 2 1116600 0) 
[   35.023400] (2 1 3 1 3074) 
[   35.024655] (2 2 4 200 3273) PASSED
[   38.154182] Testing ftrace recursion: PASSED
[   38.921470] Testing ftrace recursion safe: PASSED
[   39.687688] Testing ftrace regs: PASSED
[   40.462198] Testing tracer nop: PASSED
[   40.466389] Testing tracer irqsoff: PASSED
[   48.407206] Testing tracer preemptoff: PASSED
[   56.413646] Testing tracer preemptirqsoff: PASSED
[   64.506770] Testing tracer wakeup: PASSED
[   72.330196] Testing tracer wakeup_rt: PASSED
[   80.131803] Testing tracer wakeup_dl: PASSED
[   87.972631] Testing tracer function_graph: 
[   91.178997] 
[   91.184432] =============================
[   91.188301] WARNING: suspicious RCU usage
[   91.192316] 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25 Tainted: G        W        
[   91.197536] -----------------------------
[   91.201431] kernel/trace/trace_preemptirq.c:78 RCU not watching trace_hardirqs_off()!
[   91.206546] 
[   91.206546] other info that might help us debug this:
[   91.206546] 
[   91.211790] 
[   91.211790] rcu_scheduler_active = 2, debug_locks = 0
[   91.216454] RCU used illegally from extended quiescent state!
[   91.220890] no locks held by swapper/0/0.
[   91.224712] 
[   91.224712] stack backtrace:
[   91.228794] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W         5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25
[   91.234877] Hardware name: linux,dummy-virt (DT)
[   91.239032] Call trace:
[   91.242587]  dump_backtrace+0x0/0x240
[   91.246500]  show_stack+0x34/0x88
[   91.250295]  dump_stack+0x140/0x1bc
[   91.254159]  lockdep_rcu_suspicious+0xe4/0xf8
[   91.258332]  trace_hardirqs_off+0x214/0x330
[   91.262462]  trace_graph_return+0x1ac/0x1d8
[   91.266564]  ftrace_return_to_handler+0xa4/0x170
[   91.270809]  return_to_handler+0x1c/0x38
[   91.274826]  default_idle_call+0x94/0x38c
[   91.278869]  do_idle+0x240/0x290
[   91.282633]  rest_init+0x1e8/0x2dc
[   91.286529]  arch_call_rest_init+0x1c/0x28
[   91.290585]  start_kernel+0x638/0x670
[   91.295524] WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:5279 check_flags.part.0+0x1d4/0x1f8
[   91.296302] Modules linked in:
[   91.297644] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25
[   91.298317] Hardware name: linux,dummy-virt (DT)
[   91.298975] pstate: 80000085 (Nzcv daIf -PAN -UAO -TCO BTYPE=--)
[   91.299648] pc : check_flags.part.0+0x1d4/0x1f8
[   91.300303] lr : check_flags.part.0+0x1d4/0x1f8
[   91.300960] sp : ffffdb60f8d73a50
[   91.301628] x29: ffffdb60f8d73a50 x28: ffffdb60f8d84000 
[   91.303527] x27: ffffdb60f869cbb8 x26: ffffdb60f6835930 
[   91.305431] x25: 0000000000000000 x24: 0000000000000000 
[   91.307343] x23: ffffdb60f8daf360 x22: 0000000000000001 
[   91.309242] x21: 0000000000000000 x20: 0000000000000001 
[   91.311145] x19: ffffdb60f9bcf000 x18: 00000000749f6e65 
[   91.313044] x17: 00000000dcd3f761 x16: 0000000000000005 
[   91.314954] x15: 0000000000000000 x14: 0000000000000028 
[   91.316854] x13: 000000000000067a x12: 0000000000000028 
[   91.318753] x11: 0101010101010101 x10: ffffdb60f8d73820 
[   91.320657] x9 : ffffdb60f6960ff8 x8 : 4e5241575f534b43 
[   91.322582] x7 : 4f4c5f4755424544 x6 : ffff4454fdbd3667 
[   91.324486] x5 : 00000000ffffffc8 x4 : ffff4454fdbd2c60 
[   91.326413] x3 : ffffdb60f6800000 x2 : ffffdb60f7c60000 
[   91.328308] x1 : 1c0af7741e0f0c00 x0 : 0000000000000000 
[   91.330227] Call trace:
[   91.330880]  check_flags.part.0+0x1d4/0x1f8
[   91.331547]  lock_acquire+0x208/0x508
[   91.332200]  _raw_spin_lock+0x5c/0x80
[   91.332849]  vprintk_emit+0xb4/0x380
[   91.333528]  vprintk_default+0x4c/0x60
[   91.334189]  vprintk_func+0x120/0x330
[   91.334863]  printk+0x78/0x9c
[   91.335523]  lockdep_rcu_suspicious+0x2c/0xf8
[   91.336195]  trace_hardirqs_off+0x214/0x330
[   91.336854]  trace_graph_return+0x1ac/0x1d8
[   91.337518]  ftrace_return_to_handler+0xa4/0x170
[   91.338190]  return_to_handler+0x1c/0x38
[   91.338841]  default_idle_call+0x94/0x38c
[   91.339512]  do_idle+0x240/0x290
[   91.340166]  rest_init+0x1e8/0x2dc
[   91.340840]  arch_call_rest_init+0x1c/0x28
[   91.341499]  start_kernel+0x638/0x670
[   91.342147] irq event stamp: 1727
[   91.342832] hardirqs last  enabled at (1727): [<ffffdb60f7c33094>] exit_el1_irq_or_nmi+0x24/0x50
[   91.343502] hardirqs last disabled at (1724): [<ffffdb60f7c33060>] enter_el1_irq_or_nmi+0x20/0x30
[   91.344193] softirqs last  enabled at (1726): [<ffffdb60f6835930>] return_to_handler+0x0/0x38
[   91.344866] softirqs last disabled at (1725): [<ffffdb60f68c6880>] irq_enter_rcu+0x88/0xa8
[   91.345546] ---[ end trace e131d25144579308 ]---
[   91.346413] 
[   91.347055] 
[   91.347707] =============================
[   91.348363] WARNING: suspicious RCU usage
[   91.349058] 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25 Not tainted
[   91.349714] -----------------------------
[   91.350398] include/trace/events/ipi.h:19 suspicious rcu_dereference_check() usage!
[   91.351025] 
[   91.351702] other info that might help us debug this:
[   91.352324] 
[   91.352949] 
[   91.353626] rcu_scheduler_active = 2, debug_locks = 1
[   91.354291] RCU used illegally from extended quiescent state!
[   91.354965] no locks held by swapper/0/0.
[   91.355590] 
[   91.356257] stack backtrace:
[   91.356937] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25
[   91.357611] Hardware name: linux,dummy-virt (DT)
[   91.358270] Call trace:
[   91.358925]  dump_backtrace+0x0/0x240
[   91.359597]  show_stack+0x34/0x88
[   91.360255]  dump_stack+0x140/0x1bc
[   91.360932]  lockdep_rcu_suspicious+0xe4/0xf8
[   91.361594]  smp_cross_call+0x220/0x228
[   91.362264]  arch_irq_work_raise+0x40/0x50
[   91.362925]  __irq_work_queue_local+0xb0/0xe8
[   91.363580]  irq_work_queue+0x5c/0xb8
[   91.364252]  printk_safe_log_store+0x1a0/0x1d8
[   91.364906]  vprintk_func+0x23c/0x330
[   91.365566]  printk+0x78/0x9c
[   91.366215]  lockdep_rcu_suspicious+0x2c/0xf8
[   91.366883]  lock_acquire+0x340/0x508
[   91.367538]  _raw_spin_lock+0x5c/0x80
[   91.368192]  vprintk_emit+0xb4/0x380
[   91.368866]  vprintk_default+0x4c/0x60
[   91.369521]  vprintk_func+0x120/0x330
[   91.370191]  printk+0x78/0x9c
[   91.370845]  lockdep_rcu_suspicious+0x2c/0xf8
[   91.371519]  trace_hardirqs_off+0x214/0x330
[   91.372172]  trace_graph_return+0x1ac/0x1d8
[   91.372842]  ftrace_return_to_handler+0xa4/0x170
[   91.373503]  return_to_handler+0x1c/0x38
[   91.374158]  default_idle_call+0x94/0x38c
[   91.374825]  do_idle+0x240/0x290
[   91.375479]  rest_init+0x1e8/0x2dc
[   91.376152]  arch_call_rest_init+0x1c/0x28
[   91.376804]  start_kernel+0x638/0x670
[   91.377475] =============================
[   91.378132] WARNING: suspicious RCU usage
[   91.378793] 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25 Not tainted
[   91.379466] -----------------------------
[   91.380129] include/trace/events/lock.h:13 suspicious rcu_dereference_check() usage!
[   91.380769] 
[   91.381432] other info that might help us debug this:
[   91.382066] 
[   91.382690] 
[   91.383349] rcu_scheduler_active = 2, debug_locks = 1
[   91.384023] RCU used illegally from extended quiescent state!
[   91.384675] no locks held by swapper/0/0.
[   91.385316] 
[   91.385962] stack backtrace:
[   91.386647] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25
[   91.387307] Hardware name: linux,dummy-virt (DT)
[   91.387956] Call trace:
[   91.388626]  dump_backtrace+0x0/0x240
[   91.389283]  show_stack+0x34/0x88
[   91.389952]  dump_stack+0x140/0x1bc
[   91.390602]  lockdep_rcu_suspicious+0xe4/0xf8
[   91.391270]  lock_acquire+0x340/0x508
[   91.391926]  _raw_spin_lock+0x5c/0x80
[   91.392580]  vprintk_emit+0xb4/0x380
[   91.393259]  vprintk_default+0x4c/0x60
[   91.393913]  vprintk_func+0x120/0x330
[   91.394581]  printk+0x78/0x9c
[   91.395230]  lockdep_rcu_suspicious+0x2c/0xf8
[   91.395899]  trace_hardirqs_off+0x214/0x330
[   91.396555]  trace_graph_return+0x1ac/0x1d8
[   91.397243]  ftrace_return_to_handler+0xa4/0x170
[   91.397901]  return_to_handler+0x1c/0x38
[   91.398556]  default_idle_call+0x94/0x38c
[   91.399231]  do_idle+0x240/0x290
[   91.399883]  rest_init+0x1e8/0x2dc
[   91.400562]  arch_call_rest_init+0x1c/0x28
[   91.401227]  start_kernel+0x638/0x670
[   91.401909] ------------[ cut here ]------------
[   91.402584] DEBUG_LOCKS_WARN_ON(lockdep_hardirqs_enabled())possible reason: unannotated irqs-off.
[   91.403248] irq event stamp: 1727
[   91.403939] hardirqs last  enabled at (1727): [<ffffdb60f7c33094>] exit_el1_irq_or_nmi+0x24/0x50
[   91.404614] hardirqs last disabled at (1724): [<ffffdb60f7c33060>] enter_el1_irq_or_nmi+0x20/0x30
[   91.405305] softirqs last  enabled at (1726): [<ffffdb60f6835930>] return_to_handler+0x0/0x38
[   91.405976] softirqs last disabled at (1725): [<ffffdb60f68c6880>] irq_enter_rcu+0x88/0xa8
[   94.124678] PASSED
[   94.137271] pinctrl core: initialized pinctrl subsystem
[   94.166010] DMI not present or invalid.
[   94.181220] NET: Registered protocol family 16
[   94.221500] DMA: preallocated 256 KiB GFP_KERNEL pool for atomic allocations
[   94.222319] DMA: preallocated 256 KiB GFP_KERNEL|GFP_DMA pool for atomic allocations
[   94.224040] DMA: preallocated 256 KiB GFP_KERNEL|GFP_DMA32 pool for atomic allocations
[   94.225379] audit: initializing netlink subsys (disabled)
[   94.232973] audit: type=2000 audit(82.136:1): state=initialized audit_enabled=0 res=1
[   94.251959] thermal_sys: Registered thermal governor 'step_wise'
[   94.252110] thermal_sys: Registered thermal governor 'power_allocator'
[   94.254016] cpuidle: using governor menu
[   94.259177] hw-breakpoint: found 6 breakpoint and 4 watchpoint registers.
[   94.260165] ASID allocator initialised with 32768 entries
[   94.280847] Serial: AMBA PL011 UART driver
[   94.897305] 9000000.pl011: ttyAMA0 at MMIO 0x9000000 (irq = 47, base_baud = 0) is a PL011 rev1
[   94.899357] printk: console [ttyAMA0] enabled
[   94.899357] printk: console [ttyAMA0] enabled
[   94.899994] printk: bootconsole [pl11] disabled
[   94.899994] printk: bootconsole [pl11] disabled
[   95.136385] HugeTLB registered 1.00 GiB page size, pre-allocated 0 pages
[   95.136940] HugeTLB registered 32.0 MiB page size, pre-allocated 0 pages
[   95.137256] HugeTLB registered 2.00 MiB page size, pre-allocated 0 pages
[   95.137555] HugeTLB registered 64.0 KiB page size, pre-allocated 0 pages
[   95.172131] cryptd: max_cpu_qlen set to 1000
[   95.238749] ACPI: Interpreter disabled.
[   95.280884] iommu: Default domain type: Translated 
[   95.286381] vgaarb: loaded
[   95.292824] SCSI subsystem initialized
[   95.295892] libata version 3.00 loaded.
[   95.301200] usbcore: registered new interface driver usbfs
[   95.302249] usbcore: registered new interface driver hub
[   95.303362] usbcore: registered new device driver usb
[   95.319691] pps_core: LinuxPPS API ver. 1 registered
[   95.319974] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <[email protected]>
[   95.320522] PTP clock support registered
[   95.324309] EDAC MC: Ver: 3.0.0
[   95.356513] FPGA manager framework
[   95.358764] Advanced Linux Sound Architecture Driver Initialized.
[   95.379906] clocksource: Switched to clocksource arch_sys_counter
[  109.397497] VFS: Disk quotas dquot_6.6.0
[  109.398763] VFS: Dquot-cache hash table entries: 512 (order 0, 4096 bytes)
[  109.404469] pnp: PnP ACPI: disabled
[  109.525997] NET: Registered protocol family 2
[  109.539351] tcp_listen_portaddr_hash hash table entries: 1024 (order: 4, 81920 bytes, linear)
[  109.541579] TCP established hash table entries: 16384 (order: 5, 131072 bytes, linear)
[  109.546171] TCP bind hash table entries: 16384 (order: 8, 1179648 bytes, linear)
[  109.550508] TCP: Hash tables configured (established 16384 bind 16384)
[  109.553087] UDP hash table entries: 1024 (order: 5, 163840 bytes, linear)
[  109.554809] UDP-Lite hash table entries: 1024 (order: 5, 163840 bytes, linear)
[  109.558939] NET: Registered protocol family 1
[  109.569986] RPC: Registered named UNIX socket transport module.
[  109.570338] RPC: Registered udp transport module.
[  109.570584] RPC: Registered tcp transport module.
[  109.570826] RPC: Registered tcp NFSv4.1 backchannel transport module.
[  109.571261] PCI: CLS 0 bytes, default 64
[  109.591131] hw perfevents: enabled with armv8_pmuv3 PMU driver, 5 counters available
[  109.592826] kvm [1]: HYP mode not available
[  109.700178] Initialise system trusted keyrings
[  109.703933] workingset: timestamp_bits=44 max_order=19 bucket_order=0
[  109.829691] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[  109.839361] NFS: Registering the id_resolver key type
[  109.840697] Key type id_resolver registered
[  109.841002] Key type id_legacy registered
[  109.842732] nfs4filelayout_init: NFSv4 File Layout Driver Registering...
[  109.846885] 9p: Installing v9fs 9p2000 file system support
[  109.923870] Key type asymmetric registered
[  109.924235] Asymmetric key parser 'x509' registered
[  109.925108] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 245)
[  109.925557] io scheduler mq-deadline registered
[  109.925920] io scheduler kyber registered
[  110.181262] pl061_gpio 9030000.pl061: PL061 GPIO chip registered
[  110.220260] pci-host-generic 4010000000.pcie: host bridge /pcie@10000000 ranges:
[  110.221906] pci-host-generic 4010000000.pcie:       IO 0x003eff0000..0x003effffff -> 0x0000000000
[  110.223253] pci-host-generic 4010000000.pcie:      MEM 0x0010000000..0x003efeffff -> 0x0010000000
[  110.224080] pci-host-generic 4010000000.pcie:      MEM 0x8000000000..0xffffffffff -> 0x8000000000
[  110.226250] pci-host-generic 4010000000.pcie: ECAM at [mem 0x4010000000-0x401fffffff] for [bus 00-ff]
[  110.229496] pci-host-generic 4010000000.pcie: PCI host bridge to bus 0000:00
[  110.230080] pci_bus 0000:00: root bus resource [bus 00-ff]
[  110.230473] pci_bus 0000:00: root bus resource [io  0x0000-0xffff]
[  110.230784] pci_bus 0000:00: root bus resource [mem 0x10000000-0x3efeffff]
[  110.231097] pci_bus 0000:00: root bus resource [mem 0x8000000000-0xffffffffff]
[  110.233438] pci 0000:00:00.0: [1b36:0008] type 00 class 0x060000
[  110.243007] pci 0000:00:01.0: [1af4:1009] type 00 class 0x000200
[  110.244685] pci 0000:00:01.0: reg 0x10: [io  0x0000-0x003f]
[  110.246053] pci 0000:00:01.0: reg 0x14: [mem 0x00000000-0x00000fff]
[  110.250653] pci 0000:00:01.0: reg 0x20: [mem 0x00000000-0x00003fff 64bit pref]
[  110.260991] pci 0000:00:02.0: [1af4:1009] type 00 class 0x000200
[  110.262072] pci 0000:00:02.0: reg 0x10: [io  0x0000-0x003f]
[  110.262820] pci 0000:00:02.0: reg 0x14: [mem 0x00000000-0x00000fff]
[  110.264321] pci 0000:00:02.0: reg 0x20: [mem 0x00000000-0x00003fff 64bit pref]
[  110.269991] pci 0000:00:03.0: [1af4:1000] type 00 class 0x020000
[  110.270750] pci 0000:00:03.0: reg 0x10: [io  0x0000-0x001f]
[  110.271274] pci 0000:00:03.0: reg 0x14: [mem 0x00000000-0x00000fff]
[  110.272464] pci 0000:00:03.0: reg 0x20: [mem 0x00000000-0x00003fff 64bit pref]
[  110.273043] pci 0000:00:03.0: reg 0x30: [mem 0x00000000-0x0003ffff pref]
[  110.278520] pci 0000:00:04.0: [1af4:1004] type 00 class 0x010000
[  110.279261] pci 0000:00:04.0: reg 0x10: [io  0x0000-0x003f]
[  110.280022] pci 0000:00:04.0: reg 0x14: [mem 0x00000000-0x00000fff]
[  110.280997] pci 0000:00:04.0: reg 0x20: [mem 0x00000000-0x00003fff 64bit pref]
[  110.293126] pci 0000:00:03.0: BAR 6: assigned [mem 0x10000000-0x1003ffff pref]
[  110.293948] pci 0000:00:01.0: BAR 4: assigned [mem 0x8000000000-0x8000003fff 64bit pref]
[  110.294793] pci 0000:00:02.0: BAR 4: assigned [mem 0x8000004000-0x8000007fff 64bit pref]
[  110.295597] pci 0000:00:03.0: BAR 4: assigned [mem 0x8000008000-0x800000bfff 64bit pref]
[  110.296522] pci 0000:00:04.0: BAR 4: assigned [mem 0x800000c000-0x800000ffff 64bit pref]
[  110.297205] pci 0000:00:01.0: BAR 1: assigned [mem 0x10040000-0x10040fff]
[  110.297717] pci 0000:00:02.0: BAR 1: assigned [mem 0x10041000-0x10041fff]
[  110.298201] pci 0000:00:03.0: BAR 1: assigned [mem 0x10042000-0x10042fff]
[  110.298701] pci 0000:00:04.0: BAR 1: assigned [mem 0x10043000-0x10043fff]
[  110.299193] pci 0000:00:01.0: BAR 0: assigned [io  0x1000-0x103f]
[  110.299921] pci 0000:00:02.0: BAR 0: assigned [io  0x1040-0x107f]
[  110.300409] pci 0000:00:04.0: BAR 0: assigned [io  0x1080-0x10bf]
[  110.300883] pci 0000:00:03.0: BAR 0: assigned [io  0x10c0-0x10df]
[  110.359603] EINJ: ACPI disabled.
[  110.756520] virtio-pci 0000:00:01.0: enabling device (0000 -> 0003)
[  110.766562] virtio-pci 0000:00:02.0: enabling device (0000 -> 0003)
[  110.774880] virtio-pci 0000:00:03.0: enabling device (0000 -> 0003)
[  110.781745] virtio-pci 0000:00:04.0: enabling device (0000 -> 0003)
[  110.894006] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[  110.949875] SuperH (H)SCI(F) driver initialized
[  110.962431] msm_serial: driver initialized
[  110.995190] cacheinfo: Unable to detect cache hierarchy for CPU 0
[  111.135917] loop: module loaded
[  111.155979] megasas: 07.714.04.00-rc1
[  111.179577] scsi host0: Virtio SCSI HBA
[  111.201653] scsi 0:0:0:0: Direct-Access     QEMU     QEMU HARDDISK    2.5+ PQ: 0 ANSI: 5
[  112.559093] random: fast init done
[  112.595812] sd 0:0:0:0: Power-on or device reset occurred
[  112.611860] sd 0:0:0:0: [sda] 524288 512-byte logical blocks: (268 MB/256 MiB)
[  112.613211] sd 0:0:0:0: [sda] Write Protect is off
[  112.613728] sd 0:0:0:0: [sda] Mode Sense: 63 00 00 08
[  112.620764] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[  112.623873] sda: detected capacity change from 0 to 268435456
[  112.697968] physmap-flash 0.flash: physmap platform flash device: [mem 0x00000000-0x03ffffff]
[  112.704568] 0.flash: Found 2 x16 devices at 0x0 in 32-bit bank. Manufacturer ID 0x000000 Chip ID 0x000000
[  112.705537] Intel/Sharp Extended Query Table at 0x0031
[  112.706704] Using buffer write method
[  112.707437] erase region 0: offset=0x0,size=0x40000,blocks=256
[  112.714453] physmap-flash 0.flash: physmap platform flash device: [mem 0x04000000-0x07ffffff]
[  112.715449] 0.flash: Found 2 x16 devices at 0x0 in 32-bit bank. Manufacturer ID 0x000000 Chip ID 0x000000
[  112.716117] Intel/Sharp Extended Query Table at 0x0031
[  112.717014] Using buffer write method
[  112.717344] erase region 0: offset=0x0,size=0x40000,blocks=256
[  112.717696] Concatenating MTD devices:
[  112.717962] (0): "0.flash"
[  112.718183] (1): "0.flash"
[  112.718396] into device "0.flash"
[  112.733693] sda: detected capacity change from 0 to 268435456
[  112.734221] sd 0:0:0:0: [sda] Attached SCSI disk
[  112.868897] libphy: Fixed MDIO Bus: probed
[  112.896853] tun: Universal TUN/TAP device driver, 1.6
[  112.932681] thunder_xcv, ver 1.0
[  112.933749] thunder_bgx, ver 1.0
[  112.934733] nicpf, ver 1.0
[  112.968658] hclge is initializing
[  112.969507] hns3: Hisilicon Ethernet Network Driver for Hip08 Family - version
[  112.969832] hns3: Copyright (c) 2017 Huawei Corporation.
[  112.971113] e1000: Intel(R) PRO/1000 Network Driver
[  112.971392] e1000: Copyright (c) 1999-2006 Intel Corporation.
[  112.972667] e1000e: Intel(R) PRO/1000 Network Driver
[  112.972954] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
[  112.974131] igb: Intel(R) Gigabit Ethernet Network Driver
[  112.974412] igb: Copyright (c) 2007-2014 Intel Corporation.
[  112.975297] igbvf: Intel(R) Gigabit Virtual Function Network Driver
[  112.975775] igbvf: Copyright (c) 2009 - 2012 Intel Corporation.
[  112.985686] sky2: driver version 1.30
[  113.009304] VFIO - User Level meta-driver version: 0.3
[  113.048551] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[  113.048946] ehci-pci: EHCI PCI platform driver
[  113.049956] ehci-platform: EHCI generic platform driver
[  113.053241] ehci-orion: EHCI orion driver
[  113.056368] ehci-exynos: EHCI Exynos driver
[  113.059235] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
[  113.060113] ohci-pci: OHCI PCI platform driver
[  113.061205] ohci-platform: OHCI generic platform driver
[  113.064420] ohci-exynos: OHCI Exynos driver
[  113.075583] usbcore: registered new interface driver usb-storage
[  113.146880] rtc-pl031 9010000.pl031: registered as rtc0
[  113.148308] rtc-pl031 9010000.pl031: setting system clock to 2020-11-24T13:08:31 UTC (1606223311)
[  113.164111] i2c /dev entries driver
[  113.325456] sdhci: Secure Digital Host Controller Interface driver
[  113.325754] sdhci: Copyright(c) Pierre Ossman
[  113.336779] Synopsys Designware Multimedia Card Interface Driver
[  113.363215] sdhci-pltfm: SDHCI platform and OF driver helper
[  113.400526] ledtrig-cpu: registered to indicate activity on CPUs
[  113.441824] usbcore: registered new interface driver usbhid
[  113.442164] usbhid: USB HID core driver
[  113.560589] drop_monitor: Initializing network drop monitor service
[  113.562809] NET: Registered protocol family 17
[  113.566122] 9pnet: Installing 9P2000 support
[  113.577170] Key type dns_resolver registered
[  113.581865] registered taskstats version 1
[  113.582937] Running tests on all trace events:
[  113.583197] Testing all events: OK
[  136.678315] Running tests again, along with the function tracer
[  136.683603] Running tests on all trace events:
[  136.689620] Testing all events: OK
[  349.011031] Testing ftrace filter: OK
[  349.030607] Loading compiled-in X.509 certificates
[  349.062241] input: gpio-keys as /devices/platform/gpio-keys/input/input0
[  349.080633] ALSA device list:
[  349.081036]   No soundcards found.
[  349.081340] TAP version 14
[  349.081565] 1..0
[  349.088742] uart-pl011 9000000.pl011: no DMA platform data
[  349.105332] EXT4-fs (sda): mounting ext3 file system using the ext4 subsystem
[  349.195485] EXT4-fs (sda): mounted filesystem with ordered data mode. Opts: (null)
[  349.197107] VFS: Mounted root (ext3 filesystem) readonly on device 8:0.
[  349.201501] devtmpfs: mounted
[  349.369972] Freeing unused kernel memory: 8896K
[  349.371955] Run /sbin/init as init process
[  349.372238]   with arguments:
[  349.372474]     /sbin/init
[  349.372689]   with environment:
[  349.372927]     HOME=/
[  349.373135]     TERM=linux
[  349.373345]     earlyprintk=serial
[  349.838705] EXT4-fs (sda): re-mounted. Opts: (null)
[  349.840571] ext3 filesystem being remounted at / supports timestamps until 2038 (0x7fffffff)

Paul E. McKenney

maintainer

2020-11-24 15:02 UTC #35 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 42 lines · Marco Elver

Quoted 29 lines · Mark Rutland
Quoted 20 lines · Marco Elver
Quoted 19 lines · Mark Rutland
Quoted 4 lines · Will Deacon
FWIW, arm64 is known broken wrt lockdep and irq tracing atm. Mark has been looking at that and I think he is close to having something workable.
Mark -- is there anything Marco and Paul can try out?
I initially traced some issues back to commit:
044d0d6de9f50192 ("lockdep: Only trace IRQ edges")
... and that change of semantic could cause us to miss edges in some cases, but IIUC mostly where we haven't done the right thing in exception entry/return.
I don't think my patches address this case yet, but my WIP (currently just fixing user<->kernel transitions) is at:
https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/irq-fixes
Quoted 7 lines
Quoted 4 lines
I'm looking into the kernel<->kernel transitions now, and I know that we mess up RCU management for a small window around arch_cpu_idle, but it's not immediately clear to me if either of those cases could cause this report.
Thank you -- I tried your irq-fixes, however that didn't seem to fix the problem (still get warnings and then a panic). :-/
Quoted 7 lines
I've just updated that branch with a new version which I hope covers kernel<->kernel transitions too. If you get a chance, would you mind giving that a spin?
The HEAD commit should be:
a51334f033f8ee88 ("HACK: check IRQ tracing has RCU watching")
Thank you! Your series appears to work and fixes the stalls and deadlocks (3 trials)! I noticed there are a bunch of warnings in the log that might be relevant (see attached).

Quoted 5 lines

Note, I also reverted
sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled
and that still works.

This is expected behavior given that there were no RCU CPU stall warnings. As to the warnings...

[ . . . ]

Quoted 58 lines

[   91.184432] =============================
[   91.188301] WARNING: suspicious RCU usage
[   91.192316] 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25 Tainted: G        W        
[   91.197536] -----------------------------
[   91.201431] kernel/trace/trace_preemptirq.c:78 RCU not watching trace_hardirqs_off()!
[   91.206546] 
[   91.206546] other info that might help us debug this:
[   91.206546] 
[   91.211790] 
[   91.211790] rcu_scheduler_active = 2, debug_locks = 0
[   91.216454] RCU used illegally from extended quiescent state!
[   91.220890] no locks held by swapper/0/0.
[   91.224712] 
[   91.224712] stack backtrace:
[   91.228794] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W         5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25
[   91.234877] Hardware name: linux,dummy-virt (DT)
[   91.239032] Call trace:
[   91.242587]  dump_backtrace+0x0/0x240
[   91.246500]  show_stack+0x34/0x88
[   91.250295]  dump_stack+0x140/0x1bc
[   91.254159]  lockdep_rcu_suspicious+0xe4/0xf8
[   91.258332]  trace_hardirqs_off+0x214/0x330
[   91.262462]  trace_graph_return+0x1ac/0x1d8
[   91.266564]  ftrace_return_to_handler+0xa4/0x170
[   91.270809]  return_to_handler+0x1c/0x38
[   91.274826]  default_idle_call+0x94/0x38c
[   91.278869]  do_idle+0x240/0x290
[   91.282633]  rest_init+0x1e8/0x2dc
[   91.286529]  arch_call_rest_init+0x1c/0x28
[   91.290585]  start_kernel+0x638/0x670
[   91.295524] WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:5279 check_flags.part.0+0x1d4/0x1f8
[   91.296302] Modules linked in:
[   91.297644] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25
[   91.298317] Hardware name: linux,dummy-virt (DT)
[   91.298975] pstate: 80000085 (Nzcv daIf -PAN -UAO -TCO BTYPE=--)
[   91.299648] pc : check_flags.part.0+0x1d4/0x1f8
[   91.300303] lr : check_flags.part.0+0x1d4/0x1f8
[   91.300960] sp : ffffdb60f8d73a50
[   91.301628] x29: ffffdb60f8d73a50 x28: ffffdb60f8d84000 
[   91.303527] x27: ffffdb60f869cbb8 x26: ffffdb60f6835930 
[   91.305431] x25: 0000000000000000 x24: 0000000000000000 
[   91.307343] x23: ffffdb60f8daf360 x22: 0000000000000001 
[   91.309242] x21: 0000000000000000 x20: 0000000000000001 
[   91.311145] x19: ffffdb60f9bcf000 x18: 00000000749f6e65 
[   91.313044] x17: 00000000dcd3f761 x16: 0000000000000005 
[   91.314954] x15: 0000000000000000 x14: 0000000000000028 
[   91.316854] x13: 000000000000067a x12: 0000000000000028 
[   91.318753] x11: 0101010101010101 x10: ffffdb60f8d73820 
[   91.320657] x9 : ffffdb60f6960ff8 x8 : 4e5241575f534b43 
[   91.322582] x7 : 4f4c5f4755424544 x6 : ffff4454fdbd3667 
[   91.324486] x5 : 00000000ffffffc8 x4 : ffff4454fdbd2c60 
[   91.326413] x3 : ffffdb60f6800000 x2 : ffffdb60f7c60000 
[   91.328308] x1 : 1c0af7741e0f0c00 x0 : 0000000000000000 
[   91.330227] Call trace:
[   91.330880]  check_flags.part.0+0x1d4/0x1f8
[   91.331547]  lock_acquire+0x208/0x508
[   91.332200]  _raw_spin_lock+0x5c/0x80
[   91.332849]  vprintk_emit+0xb4/0x380

Quoted 8 lines

[   91.333528]  vprintk_default+0x4c/0x60
[   91.334189]  vprintk_func+0x120/0x330
[   91.334863]  printk+0x78/0x9c
[   91.335523]  lockdep_rcu_suspicious+0x2c/0xf8
[   91.336195]  trace_hardirqs_off+0x214/0x330
[   91.336854]  trace_graph_return+0x1ac/0x1d8
[   91.337518]  ftrace_return_to_handler+0xa4/0x170
[   91.338190]  return_to_handler+0x1c/0x38

This looks like tracing in the idle loop in a place where RCU is not watching. Historically, this has been addressed by using _rcuidle() trace events, but the portion of the idle loop that RCU is watching has recently increased. Last I checked, there were still a few holdouts (that would splat like this) in x86, though perhaps those have since been fixed.

Quoted 11 lines

[   91.338841]  default_idle_call+0x94/0x38c
[   91.339512]  do_idle+0x240/0x290
[   91.340166]  rest_init+0x1e8/0x2dc
[   91.340840]  arch_call_rest_init+0x1c/0x28
[   91.341499]  start_kernel+0x638/0x670
[   91.342147] irq event stamp: 1727
[   91.342832] hardirqs last  enabled at (1727): [<ffffdb60f7c33094>] exit_el1_irq_or_nmi+0x24/0x50
[   91.343502] hardirqs last disabled at (1724): [<ffffdb60f7c33060>] enter_el1_irq_or_nmi+0x20/0x30
[   91.344193] softirqs last  enabled at (1726): [<ffffdb60f6835930>] return_to_handler+0x0/0x38
[   91.344866] softirqs last disabled at (1725): [<ffffdb60f68c6880>] irq_enter_rcu+0x88/0xa8
[   91.345546] ---[ end trace e131d25144579308 ]---

The other warning looked similar.

Thanx, Paul

Mark Rutland

2020-11-24 19:43 UTC #36 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 32 lines · Paul E. McKenney

Quoted 22 lines · Marco Elver

[   91.184432] =============================
[   91.188301] WARNING: suspicious RCU usage
[   91.192316] 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25 Tainted: G        W        
[   91.197536] -----------------------------
[   91.201431] kernel/trace/trace_preemptirq.c:78 RCU not watching trace_hardirqs_off()!
[   91.206546] 
[   91.206546] other info that might help us debug this:
[   91.206546] 
[   91.211790] 
[   91.211790] rcu_scheduler_active = 2, debug_locks = 0
[   91.216454] RCU used illegally from extended quiescent state!
[   91.220890] no locks held by swapper/0/0.
[   91.224712] 
[   91.224712] stack backtrace:
[   91.228794] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W         5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25
[   91.234877] Hardware name: linux,dummy-virt (DT)
[   91.239032] Call trace:
[   91.242587]  dump_backtrace+0x0/0x240
[   91.246500]  show_stack+0x34/0x88
[   91.250295]  dump_stack+0x140/0x1bc
[   91.254159]  lockdep_rcu_suspicious+0xe4/0xf8
[   91.258332]  trace_hardirqs_off+0x214/0x330

Quoted 8 lines

[   91.262462]  trace_graph_return+0x1ac/0x1d8
[   91.266564]  ftrace_return_to_handler+0xa4/0x170
[   91.270809]  return_to_handler+0x1c/0x38
[   91.274826]  default_idle_call+0x94/0x38c
[   91.278869]  do_idle+0x240/0x290
[   91.282633]  rest_init+0x1e8/0x2dc
[   91.286529]  arch_call_rest_init+0x1c/0x28
[   91.290585]  start_kernel+0x638/0x670

Quoted 5 lines

This looks like tracing in the idle loop in a place where RCU is not watching. Historically, this has been addressed by using _rcuidle() trace events, but the portion of the idle loop that RCU is watching has recently increased. Last I checked, there were still a few holdouts (that would splat like this) in x86, though perhaps those have since been fixed.

Yup! I think this is a latent issue my debug hacks revealed (in addition to a couple of other issues in the idle path), and still affects x86 and others. It's only noticeable if you hack trace_hardirqs_{on,off}() to check rcu_is_watching(), which I had at the tip of my tree.

AFAICT, the issue is that arch_cpu_idle() can be dynamically traced with ftrace, and hence the tracing code can unexpectedly run without RCU watching. Since that's dynamic tracing, we can avoid it by marking arch_cpu_idle() and friends as noinstr.

I'll see about getting this fixed before we upstream the debug hack.

Thanks,
Mark.

Steven Rostedt

maintainer

2020-11-24 20:32 UTC #37 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 4 lines · On Tue, 24 Nov 2020 19:43:08 +0000 Mark Rutland <[email protected]> wrote:

AFAICT, the issue is that arch_cpu_idle() can be dynamically traced with ftrace, and hence the tracing code can unexpectedly run without RCU watching. Since that's dynamic tracing, we can avoid it by marking arch_cpu_idle() and friends as noinstr.

Technically, ftrace doesn't care if RCU is watching or not, but the callbacks might, and they need to do the rcu_is_watching() check if they do.

Although, there's work to keep those areas from being traced, but to do so, they really need to be minimal, where you don't ever want to trace them.

-- Steve

Mark Rutland

2020-11-24 19:30 UTC #38 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

In reply to Marco Elver

Quoted 34 lines · Marco Elver

Quoted 33 lines · Mark Rutland
Quoted 20 lines · Marco Elver
Quoted 19 lines · Mark Rutland
Quoted 4 lines · Will Deacon
FWIW, arm64 is known broken wrt lockdep and irq tracing atm. Mark has been looking at that and I think he is close to having something workable.
Mark -- is there anything Marco and Paul can try out?
I initially traced some issues back to commit:
044d0d6de9f50192 ("lockdep: Only trace IRQ edges")
... and that change of semantic could cause us to miss edges in some cases, but IIUC mostly where we haven't done the right thing in exception entry/return.
I don't think my patches address this case yet, but my WIP (currently just fixing user<->kernel transitions) is at:
https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/irq-fixes
Quoted 7 lines
Quoted 4 lines
I'm looking into the kernel<->kernel transitions now, and I know that we mess up RCU management for a small window around arch_cpu_idle, but it's not immediately clear to me if either of those cases could cause this report.
Thank you -- I tried your irq-fixes, however that didn't seem to fix the problem (still get warnings and then a panic). :-/
I've just updated that branch with a new version which I hope covers kernel<->kernel transitions too. If you get a chance, would you mind giving that a spin?

Quoted 6 lines

Quoted 3 lines
The HEAD commit should be:
a51334f033f8ee88 ("HACK: check IRQ tracing has RCU watching")
Thank you! Your series appears to work and fixes the stalls and deadlocks (3 trials)!

Thanks for testing! I'm glad that appears to work, as it suggests there's not another massive problem lurking in this area.

While cleaning/splitting that up today, I spotted a couple of new problems I introduced, and I'm part-way through sorting that out, but it's not quite ready today after all. :/

Fingers crossed for tomorrow...

Quoted 25 lines

I noticed there are a bunch of warnings in the log that might be relevant (see attached).

[   91.184432] =============================
[   91.188301] WARNING: suspicious RCU usage
[   91.192316] 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25 Tainted: G        W        
[   91.197536] -----------------------------
[   91.201431] kernel/trace/trace_preemptirq.c:78 RCU not watching trace_hardirqs_off()!
[   91.206546] 
[   91.206546] other info that might help us debug this:
[   91.206546] 
[   91.211790] 
[   91.211790] rcu_scheduler_active = 2, debug_locks = 0
[   91.216454] RCU used illegally from extended quiescent state!
[   91.220890] no locks held by swapper/0/0.
[   91.224712] 
[   91.224712] stack backtrace:
[   91.228794] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W         5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25
[   91.234877] Hardware name: linux,dummy-virt (DT)
[   91.239032] Call trace:
[   91.242587]  dump_backtrace+0x0/0x240
[   91.246500]  show_stack+0x34/0x88
[   91.250295]  dump_stack+0x140/0x1bc
[   91.254159]  lockdep_rcu_suspicious+0xe4/0xf8
[   91.258332]  trace_hardirqs_off+0x214/0x330

Quoted 8 lines

[   91.262462]  trace_graph_return+0x1ac/0x1d8
[   91.266564]  ftrace_return_to_handler+0xa4/0x170
[   91.270809]  return_to_handler+0x1c/0x38
[   91.274826]  default_idle_call+0x94/0x38c
[   91.278869]  do_idle+0x240/0x290
[   91.282633]  rest_init+0x1e8/0x2dc
[   91.286529]  arch_call_rest_init+0x1c/0x28
[   91.290585]  start_kernel+0x638/0x670

Hmm... I suspect that arch_cpu_idle() is being traced here, and I reckon we have to mark that and its callees as noinstr, since it doesn't seem sane to have ftrace check whether RCU is watching for every function call. Maybe Paul or Steve can correct me. ;)

If you still have the binary lying around, can you check whether default_idle_call+0x94/0x38c is just after the call to arch_cpu_idle()? If you could dump the asm around that, along with whatever faddr2line tells you, that'd be a great help.

This looks like it should be reproducible, so I'll enable the boot-time self tests in my kernel and check whether I see the above too.

Thanks,
Mark.

Marco Elver

author maintainer

2020-11-25 09:45 UTC #39 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

On Tue, Nov 24, 2020 at 07:30PM +0000, Mark Rutland wrote:
[...]

Quoted 54 lines

Quoted 10 lines
Quoted 7 lines
I've just updated that branch with a new version which I hope covers kernel<->kernel transitions too. If you get a chance, would you mind giving that a spin?
The HEAD commit should be:
a51334f033f8ee88 ("HACK: check IRQ tracing has RCU watching")
Thank you! Your series appears to work and fixes the stalls and deadlocks (3 trials)!
Thanks for testing! I'm glad that appears to work, as it suggests there's not another massive problem lurking in this area.
While cleaning/splitting that up today, I spotted a couple of new problems I introduced, and I'm part-way through sorting that out, but it's not quite ready today after all. :/
Fingers crossed for tomorrow...
Quoted 25 lines
I noticed there are a bunch of warnings in the log that might be relevant (see attached).
[   91.184432] =============================
[   91.188301] WARNING: suspicious RCU usage
[   91.192316] 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25 Tainted: G        W        
[   91.197536] -----------------------------
[   91.201431] kernel/trace/trace_preemptirq.c:78 RCU not watching trace_hardirqs_off()!
[   91.206546] 
[   91.206546] other info that might help us debug this:
[   91.206546] 
[   91.211790] 
[   91.211790] rcu_scheduler_active = 2, debug_locks = 0
[   91.216454] RCU used illegally from extended quiescent state!
[   91.220890] no locks held by swapper/0/0.
[   91.224712] 
[   91.224712] stack backtrace:
[   91.228794] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W         5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25
[   91.234877] Hardware name: linux,dummy-virt (DT)
[   91.239032] Call trace:
[   91.242587]  dump_backtrace+0x0/0x240
[   91.246500]  show_stack+0x34/0x88
[   91.250295]  dump_stack+0x140/0x1bc
[   91.254159]  lockdep_rcu_suspicious+0xe4/0xf8
[   91.258332]  trace_hardirqs_off+0x214/0x330
Quoted 8 lines
[   91.262462]  trace_graph_return+0x1ac/0x1d8
[   91.266564]  ftrace_return_to_handler+0xa4/0x170
[   91.270809]  return_to_handler+0x1c/0x38
[   91.274826]  default_idle_call+0x94/0x38c
[   91.278869]  do_idle+0x240/0x290
[   91.282633]  rest_init+0x1e8/0x2dc
[   91.286529]  arch_call_rest_init+0x1c/0x28
[   91.290585]  start_kernel+0x638/0x670

Quoted 4 lines

Hmm... I suspect that arch_cpu_idle() is being traced here, and I reckon we have to mark that and its callees as noinstr, since it doesn't seem sane to have ftrace check whether RCU is watching for every function call. Maybe Paul or Steve can correct me. ;)

Yes, it's arch_cpu_idle().

Quoted 4 lines

If you still have the binary lying around, can you check whether default_idle_call+0x94/0x38c is just after the call to arch_cpu_idle()? If you could dump the asm around that, along with whatever faddr2line tells you, that'd be a great help.

I reran to be sure, with similar results. I've attached a syz-symbolize'd version of the warnings.

Thanks,
-- Marco

sched: DL replenish lagged too much
PASSED
Testing tracer wakeup_dl: PASSED
Testing tracer function_graph:
=============================
WARNING: suspicious RCU usage
5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25 Tainted: G W
-----------------------------
kernel/trace/trace_preemptirq.c:78 RCU not watching trace_hardirqs_off()!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 0
RCU used illegally from extended quiescent state!
no locks held by swapper/0/0.

stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W         5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x140/0x1bc lib/dump_stack.c:120
 lockdep_rcu_suspicious+0xe4/0xf8 kernel/locking/lockdep.c:6353
 trace_hardirqs_off+0x214/0x330 kernel/trace/trace_preemptirq.c:78
 trace_graph_return+0x1ac/0x1d8 kernel/trace/trace_functions_graph.c:253
 ftrace_return_to_handler+0xa4/0x170 kernel/trace/fgraph.c:239
 return_to_handler+0x1c/0x38 arch/arm64/kernel/entry-ftrace.S:333
 default_idle_call+0x94/0x38c kernel/sched/idle.c:112
 cpuidle_idle_call kernel/sched/idle.c:194 [inline]
 do_idle+0x240/0x290 kernel/sched/idle.c:299
 rest_init+0x1e8/0x2dc init/main.c:722
 arch_call_rest_init+0x1c/0x28
 start_kernel+0x638/0x670 init/main.c:1066
WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:5279 check_flags.part.0+0x1d4/0x1f8 kernel/locking/lockdep.c:5279
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25
Hardware name: linux,dummy-virt (DT)
pstate: 80000085 (Nzcv daIf -PAN -UAO -TCO BTYPE=--)
pc : check_flags.part.0+0x1d4/0x1f8 kernel/locking/lockdep.c:5279
lr : check_flags.part.0+0x1d4/0x1f8 kernel/locking/lockdep.c:5279

sp : ffffa97d6cd73a50
x29: ffffa97d6cd73a50 x28: ffffa97d6cd84000
x27: ffffa97d6c69cbb8 x26: ffffa97d6a835930
x25: 0000000000000000 x24: 0000000000000000
x23: ffffa97d6cdaf360 x22: 0000000000000001
x21: 0000000000000000 x20: 0000000000000001
x19: ffffa97d6dbcf000 x18: 00000000d8c875f1
x17: 00000000bf9a23d2 x16: 0000000000000005
x15: 0000000000000000 x14: 0000000000000028
x13: 000000000000067d x12: 0000000000000028
x11: 0101010101010101 x10: ffffa97d6cd73820
x9 : ffffa97d6a960ff8 x8 : 4e5241575f534b43
x7 : 4f4c5f4755424544 x6 : ffff35ce3dbd3667
x5 : 00000000ffffffc8 x4 : ffff35ce3dbd2c60
x3 : ffffa97d6a800000 x2 : ffffa97d6bc60000
x1 : ba5fc2cb163a2c00 x0 : 0000000000000000

Call trace:
 check_flags.part.0+0x1d4/0x1f8 kernel/locking/lockdep.c:5279
 check_flags kernel/locking/lockdep.c:5275 [inline]
 lock_acquire kernel/locking/lockdep.c:5432 [inline]
 lock_acquire+0x208/0x508 kernel/locking/lockdep.c:5400
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x5c/0x80 kernel/locking/spinlock.c:151
 vprintk_emit+0xb4/0x380 kernel/printk/printk.c:2010
 vprintk_default+0x4c/0x60 kernel/printk/printk.c:2045
 vprintk_func+0x120/0x330 kernel/printk/printk_safe.c:393
 printk+0x78/0x9c kernel/printk/printk.c:2076
 lockdep_rcu_suspicious+0x2c/0xf8 kernel/locking/lockdep.c:6317
 trace_hardirqs_off+0x214/0x330 kernel/trace/trace_preemptirq.c:78
 trace_graph_return+0x1ac/0x1d8 kernel/trace/trace_functions_graph.c:253
 ftrace_return_to_handler+0xa4/0x170 kernel/trace/fgraph.c:239
 return_to_handler+0x1c/0x38 arch/arm64/kernel/entry-ftrace.S:333
 default_idle_call+0x94/0x38c kernel/sched/idle.c:112
 cpuidle_idle_call kernel/sched/idle.c:194 [inline]
 do_idle+0x240/0x290 kernel/sched/idle.c:299
 rest_init+0x1e8/0x2dc init/main.c:722
 arch_call_rest_init+0x1c/0x28
 start_kernel+0x638/0x670 init/main.c:1066
irq event stamp: 1719
hardirqs last  enabled at (1719): [<ffffa97d6bc33094>] exit_el1_irq_or_nmi+0x24/0x50 arch/arm64/kernel/entry-common.c:101
hardirqs last disabled at (1716): [<ffffa97d6bc33060>] enter_el1_irq_or_nmi+0x20/0x30 arch/arm64/kernel/entry-common.c:93
softirqs last  enabled at (1718): [<ffffa97d6a835930>] return_to_handler+0x0/0x38 arch/arm64/kernel/entry-ftrace.S:314
softirqs last disabled at (1717): [<ffffa97d6a8c6880>] irq_enter_rcu+0x88/0xa8 kernel/softirq.c:363
---[ end trace 06e986ee87545489 ]---

=============================
WARNING: suspicious RCU usage 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25 Not tainted
-----------------------------
include/trace/events/ipi.h:19 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
RCU used illegally from extended quiescent state!
no locks held by swapper/0/0.

stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x140/0x1bc lib/dump_stack.c:120
 lockdep_rcu_suspicious+0xe4/0xf8 kernel/locking/lockdep.c:6353
 trace_ipi_raise include/trace/events/ipi.h:19 [inline]
 smp_cross_call+0x220/0x228 arch/arm64/kernel/smp.c:953
 arch_irq_work_raise+0x40/0x50 arch/arm64/kernel/smp.c:840
 __irq_work_queue_local kernel/irq_work.c:59 [inline]
 __irq_work_queue_local+0xb0/0xe8 kernel/irq_work.c:53
 irq_work_queue kernel/irq_work.c:75 [inline]
 irq_work_queue+0x5c/0xb8 kernel/irq_work.c:67
 queue_flush_work kernel/printk/printk_safe.c:56 [inline]
 printk_safe_log_store+0x1a0/0x1d8 kernel/printk/printk_safe.c:107
 vprintk_safe kernel/printk/printk_safe.c:347 [inline]
 vprintk_func+0x23c/0x330 kernel/printk/printk_safe.c:390
 printk+0x78/0x9c kernel/printk/printk.c:2076
 lockdep_rcu_suspicious+0x2c/0xf8 kernel/locking/lockdep.c:6317
 trace_lock_acquire include/trace/events/lock.h:13 [inline]
 lock_acquire+0x340/0x508 kernel/locking/lockdep.c:5406
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x5c/0x80 kernel/locking/spinlock.c:151
 vprintk_emit+0xb4/0x380 kernel/printk/printk.c:2010
 vprintk_default+0x4c/0x60 kernel/printk/printk.c:2045
 vprintk_func+0x120/0x330 kernel/printk/printk_safe.c:393
 printk+0x78/0x9c kernel/printk/printk.c:2076
 lockdep_rcu_suspicious+0x2c/0xf8 kernel/locking/lockdep.c:6317
 trace_hardirqs_off+0x214/0x330 kernel/trace/trace_preemptirq.c:78
 trace_graph_return+0x1ac/0x1d8 kernel/trace/trace_functions_graph.c:253
 ftrace_return_to_handler+0xa4/0x170 kernel/trace/fgraph.c:239
 return_to_handler+0x1c/0x38 arch/arm64/kernel/entry-ftrace.S:333
 default_idle_call+0x94/0x38c kernel/sched/idle.c:112
 cpuidle_idle_call kernel/sched/idle.c:194 [inline]
 do_idle+0x240/0x290 kernel/sched/idle.c:299
 rest_init+0x1e8/0x2dc init/main.c:722
 arch_call_rest_init+0x1c/0x28
 start_kernel+0x638/0x670 init/main.c:1066
=============================

WARNING: suspicious RCU usage 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25 Not tainted
-----------------------------
include/trace/events/lock.h:13 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
RCU used illegally from extended quiescent state!
no locks held by swapper/0/0.

stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100
 show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x140/0x1bc lib/dump_stack.c:120
 lockdep_rcu_suspicious+0xe4/0xf8 kernel/locking/lockdep.c:6353
 trace_lock_acquire include/trace/events/lock.h:13 [inline]
 lock_acquire+0x340/0x508 kernel/locking/lockdep.c:5406
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x5c/0x80 kernel/locking/spinlock.c:151
 vprintk_emit+0xb4/0x380 kernel/printk/printk.c:2010
 vprintk_default+0x4c/0x60 kernel/printk/printk.c:2045
 vprintk_func+0x120/0x330 kernel/printk/printk_safe.c:393
 printk+0x78/0x9c kernel/printk/printk.c:2076
 lockdep_rcu_suspicious+0x2c/0xf8 kernel/locking/lockdep.c:6317
 trace_hardirqs_off+0x214/0x330 kernel/trace/trace_preemptirq.c:78
 trace_graph_return+0x1ac/0x1d8 kernel/trace/trace_functions_graph.c:253
 ftrace_return_to_handler+0xa4/0x170 kernel/trace/fgraph.c:239
 return_to_handler+0x1c/0x38 arch/arm64/kernel/entry-ftrace.S:333
 default_idle_call+0x94/0x38c kernel/sched/idle.c:112
 cpuidle_idle_call kernel/sched/idle.c:194 [inline]
 do_idle+0x240/0x290 kernel/sched/idle.c:299
 rest_init+0x1e8/0x2dc init/main.c:722
 arch_call_rest_init+0x1c/0x28
 start_kernel+0x638/0x670 init/main.c:1066
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(lockdep_hardirqs_enabled())possible reason: unannotated irqs-off.
irq event stamp: 1719
hardirqs last  enabled at (1719): [<ffffa97d6bc33094>] exit_el1_irq_or_nmi+0x24/0x50 arch/arm64/kernel/entry-common.c:101
hardirqs last disabled at (1716): [<ffffa97d6bc33060>] enter_el1_irq_or_nmi+0x20/0x30 arch/arm64/kernel/entry-common.c:93
softirqs last  enabled at (1718): [<ffffa97d6a835930>] return_to_handler+0x0/0x38 arch/arm64/kernel/entry-ftrace.S:314
softirqs last disabled at (1717): [<ffffa97d6a8c6880>] irq_enter_rcu+0x88/0xa8 kernel/softirq.c:363

PASSED
pinctrl core: initialized pinctrl subsystem
DMI not present or invalid.
NET: Registered protocol family 16
DMA: preallocated 256 KiB GFP_KERNEL pool for atomic allocations
DMA: preallocated 256 KiB GFP_KERNEL|GFP_DMA pool for atomic allocations
DMA: preallocated 256 KiB GFP_KERNEL|GFP_DMA32 pool for atomic allocations
audit: initializing netlink subsys (disabled)
audit: type=2000 audit(81.200:1): state=initialized audit_enabled=0 res=1
thermal_sys: Registered thermal governor 'step_wise'
thermal_sys: Registered thermal governor 'power_allocator'
cpuidle: using governor menu
hw-breakpoint: found 6 breakpoint and 4 watchpoint registers.
ASID allocator initialised with 32768 entries
Serial: AMBA PL011 UART driver
9000000.pl011: ttyAMA0 at MMIO 0x9000000 (irq = 47, base_baud = 0) is a PL011 rev1
printk: console [ttyAMA0] enabled
printk: console [ttyAMA0] enabled
printk: bootconsole [pl11] disabled
printk: bootconsole [pl11] disabled
HugeTLB registered 1.00 GiB page size, pre-allocated 0 pages
HugeTLB registered 32.0 MiB page size, pre-allocated 0 pages
HugeTLB registered 2.00 MiB page size, pre-allocated 0 pages
HugeTLB registered 64.0 KiB page size, pre-allocated 0 pages
cryptd: max_cpu_qlen set to 1000
ACPI: Interpreter disabled.
iommu: Default domain type: Translated
vgaarb: loaded
SCSI subsystem initialized
libata version 3.00 loaded.
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
pps_core: LinuxPPS API ver. 1 registered
pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <[email protected]> PTP clock support registered
EDAC MC: Ver: 3.0.0
FPGA manager framework
Advanced Linux Sound Architecture Driver Initialized.
clocksource: Switched to clocksource arch_sys_counter
VFS: Disk quotas dquot_6.6.0
VFS: Dquot-cache hash table entries: 512 (order 0, 4096 bytes)
pnp: PnP ACPI: disabled
NET: Registered protocol family 2
tcp_listen_portaddr_hash hash table entries: 1024 (order: 4, 81920 bytes, linear) TCP established hash table entries: 16384 (order: 5, 131072 bytes, linear) TCP bind hash table entries: 16384 (order: 8, 1179648 bytes, linear)
TCP: Hash tables configured (established 16384 bind 16384)
UDP hash table entries: 1024 (order: 5, 163840 bytes, linear)
UDP-Lite hash table entries: 1024 (order: 5, 163840 bytes, linear)
NET: Registered protocol family 1
RPC: Registered named UNIX socket transport module.
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
PCI: CLS 0 bytes, default 64
hw perfevents: enabled with armv8_pmuv3 PMU driver, 5 counters available kvm [1]: HYP mode not available
Initialise system trusted keyrings
workingset: timestamp_bits=44 max_order=19 bucket_order=0
squashfs: version 4.0 (2009/01/31) Phillip Lougher
NFS: Registering the id_resolver key type
Key type id_resolver registered
Key type id_legacy registered
nfs4filelayout_init: NFSv4 File Layout Driver Registering...
9p: Installing v9fs 9p2000 file system support
Key type asymmetric registered
Asymmetric key parser 'x509' registered
Block layer SCSI generic (bsg) driver version 0.4 loaded (major 245)
io scheduler mq-deadline registered
io scheduler kyber registered

pl061_gpio 9030000.pl061: PL061 GPIO chip registered
pci-host-generic 4010000000.pcie: host bridge /pcie@10000000 ranges:
pci-host-generic 4010000000.pcie:       IO 0x003eff0000..0x003effffff -> 0x0000000000
pci-host-generic 4010000000.pcie:      MEM 0x0010000000..0x003efeffff -> 0x0010000000
pci-host-generic 4010000000.pcie:      MEM 0x8000000000..0xffffffffff -> 0x8000000000
pci-host-generic 4010000000.pcie: ECAM at [mem 0x4010000000-0x401fffffff] for [bus 00-ff]
pci-host-generic 4010000000.pcie: PCI host bridge to bus 0000:00

pci_bus 0000:00: root bus resource [bus 00-ff]
pci_bus 0000:00: root bus resource [io 0x0000-0xffff]
pci_bus 0000:00: root bus resource [mem 0x10000000-0x3efeffff] pci_bus 0000:00: root bus resource [mem 0x8000000000-0xffffffffff] pci 0000:00:00.0: [1b36:0008] type 00 class 0x060000
pci 0000:00:01.0: [1af4:1009] type 00 class 0x000200
pci 0000:00:01.0: reg 0x10: [io 0x0000-0x003f]
pci 0000:00:01.0: reg 0x14: [mem 0x00000000-0x00000fff]
pci 0000:00:01.0: reg 0x20: [mem 0x00000000-0x00003fff 64bit pref] pci 0000:00:02.0: [1af4:1009] type 00 class 0x000200
pci 0000:00:02.0: reg 0x10: [io 0x0000-0x003f]
pci 0000:00:02.0: reg 0x14: [mem 0x00000000-0x00000fff]
pci 0000:00:02.0: reg 0x20: [mem 0x00000000-0x00003fff 64bit pref] pci 0000:00:03.0: [1af4:1000] type 00 class 0x020000
pci 0000:00:03.0: reg 0x10: [io 0x0000-0x001f]
pci 0000:00:03.0: reg 0x14: [mem 0x00000000-0x00000fff]
pci 0000:00:03.0: reg 0x20: [mem 0x00000000-0x00003fff 64bit pref] pci 0000:00:03.0: reg 0x30: [mem 0x00000000-0x0003ffff pref]
pci 0000:00:04.0: [1af4:1004] type 00 class 0x010000
pci 0000:00:04.0: reg 0x10: [io 0x0000-0x003f]
pci 0000:00:04.0: reg 0x14: [mem 0x00000000-0x00000fff]
pci 0000:00:04.0: reg 0x20: [mem 0x00000000-0x00003fff 64bit pref] pci 0000:00:03.0: BAR 6: assigned [mem 0x10000000-0x1003ffff pref] pci 0000:00:01.0: BAR 4: assigned [mem 0x8000000000-0x8000003fff 64bit pref] pci 0000:00:02.0: BAR 4: assigned [mem 0x8000004000-0x8000007fff 64bit pref] pci 0000:00:03.0: BAR 4: assigned [mem 0x8000008000-0x800000bfff 64bit pref] pci 0000:00:04.0: BAR 4: assigned [mem 0x800000c000-0x800000ffff 64bit pref] pci 0000:00:01.0: BAR 1: assigned [mem 0x10040000-0x10040fff] pci 0000:00:02.0: BAR 1: assigned [mem 0x10041000-0x10041fff] pci 0000:00:03.0: BAR 1: assigned [mem 0x10042000-0x10042fff] pci 0000:00:04.0: BAR 1: assigned [mem 0x10043000-0x10043fff]

pci 0000:00:01.0: BAR 0: assigned [io  0x1000-0x103f]
pci 0000:00:02.0: BAR 0: assigned [io  0x1040-0x107f]
pci 0000:00:04.0: BAR 0: assigned [io  0x1080-0x10bf]
pci 0000:00:03.0: BAR 0: assigned [io  0x10c0-0x10df]

EINJ: ACPI disabled.
virtio-pci 0000:00:01.0: enabling device (0000 -> 0003)
virtio-pci 0000:00:02.0: enabling device (0000 -> 0003)
virtio-pci 0000:00:03.0: enabling device (0000 -> 0003)
virtio-pci 0000:00:04.0: enabling device (0000 -> 0003)
Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
SuperH (H)SCI(F) driver initialized
msm_serial: driver initialized
cacheinfo: Unable to detect cache hierarchy for CPU 0
loop: module loaded
megasas: 07.714.04.00-rc1
scsi host0: Virtio SCSI HBA
scsi 0:0:0:0: Direct-Access QEMU QEMU HARDDISK 2.5+ PQ: 0 ANSI: 5
random: fast init done
sd 0:0:0:0: Power-on or device reset occurred
sd 0:0:0:0: [sda] 524288 512-byte logical blocks: (268 MB/256 MiB)
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] Mode Sense: 63 00 00 08
sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sda: detected capacity change from 0 to 268435456
physmap-flash 0.flash: physmap platform flash device: [mem 0x00000000-0x03ffffff] 0.flash: Found 2 x16 devices at 0x0 in 32-bit bank. Manufacturer ID 0x000000 Chip ID 0x000000 Intel/Sharp Extended Query Table at 0x0031
Using buffer write method
erase region 0: offset=0x0,size=0x40000,blocks=256
physmap-flash 0.flash: physmap platform flash device: [mem 0x04000000-0x07ffffff] 0.flash: Found 2 x16 devices at 0x0 in 32-bit bank. Manufacturer ID 0x000000 Chip ID 0x000000 Intel/Sharp Extended Query Table at 0x0031
Using buffer write method
erase region 0: offset=0x0,size=0x40000,blocks=256
Concatenating MTD devices:
(0): "0.flash"
(1): "0.flash"
into device "0.flash"
sda: detected capacity change from 0 to 268435456
sd 0:0:0:0: [sda] Attached SCSI disk
libphy: Fixed MDIO Bus: probed
tun: Universal TUN/TAP device driver, 1.6
thunder_xcv, ver 1.0
thunder_bgx, ver 1.0
nicpf, ver 1.0
hclge is initializing
hns3: Hisilicon Ethernet Network Driver for Hip08 Family - version
hns3: Copyright (c) 2017 Huawei Corporation.
e1000: Intel(R) PRO/1000 Network Driver
e1000: Copyright (c) 1999-2006 Intel Corporation.
e1000e: Intel(R) PRO/1000 Network Driver
e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
igb: Intel(R) Gigabit Ethernet Network Driver
igb: Copyright (c) 2007-2014 Intel Corporation.
igbvf: Intel(R) Gigabit Virtual Function Network Driver
igbvf: Copyright (c) 2009 - 2012 Intel Corporation.
sky2: driver version 1.30
VFIO - User Level meta-driver version: 0.3
ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
ehci-pci: EHCI PCI platform driver
ehci-platform: EHCI generic platform driver
ehci-orion: EHCI orion driver
ehci-exynos: EHCI Exynos driver
ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
ohci-pci: OHCI PCI platform driver
ohci-platform: OHCI generic platform driver
ohci-exynos: OHCI Exynos driver
usbcore: registered new interface driver usb-storage
rtc-pl031 9010000.pl031: registered as rtc0
rtc-pl031 9010000.pl031: setting system clock to 2020-11-25T09:39:22 UTC (1606297162) i2c /dev entries driver
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
Synopsys Designware Multimedia Card Interface Driver
sdhci-pltfm: SDHCI platform and OF driver helper
ledtrig-cpu: registered to indicate activity on CPUs
usbcore: registered new interface driver usbhid
usbhid: USB HID core driver
drop_monitor: Initializing network drop monitor service
NET: Registered protocol family 17
9pnet: Installing 9P2000 support
Key type dns_resolver registered
registered taskstats version 1
Running tests on all trace events:
Testing all events: OK
Running tests again, along with the function tracer
Running tests on all trace events:
Testing all events:
hrtimer: interrupt took 11560624 ns
OK
Testing ftrace filter: OK
Loading compiled-in X.509 certificates
input: gpio-keys as /devices/platform/gpio-keys/input/input0
ALSA device list:
No soundcards found.
TAP version 14
1..0
uart-pl011 9000000.pl011: no DMA platform data
EXT4-fs (sda): mounting ext3 file system using the ext4 subsystem
EXT4-fs (sda): mounted filesystem with ordered data mode. Opts: (null)
VFS: Mounted root (ext3 filesystem) readonly on device 8:0.
devtmpfs: mounted
Freeing unused kernel memory: 8896K
Run /sbin/init as init process
with arguments:
/sbin/init
with environment:

    HOME=/
    TERM=linux
    earlyprintk=serial

EXT4-fs (sda): re-mounted. Opts: (null)
ext3 filesystem being remounted at / supports timestamps until 2038 (0x7fffffff)
random: crng init done

Mark Rutland

2020-11-25 10:29 UTC #40 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 1 line · Marco Elver

On Tue, Nov 24, 2020 at 07:30PM +0000, Mark Rutland wrote:

[...]

Quoted 41 lines

Quoted 34 lines

Quoted 25 lines

I noticed there are a bunch of warnings in the log that might be relevant (see attached).

[   91.184432] =============================
[   91.188301] WARNING: suspicious RCU usage
[   91.192316] 5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25 Tainted: G        W        
[   91.197536] -----------------------------
[   91.201431] kernel/trace/trace_preemptirq.c:78 RCU not watching trace_hardirqs_off()!
[   91.206546] 
[   91.206546] other info that might help us debug this:
[   91.206546] 
[   91.211790] 
[   91.211790] rcu_scheduler_active = 2, debug_locks = 0
[   91.216454] RCU used illegally from extended quiescent state!
[   91.220890] no locks held by swapper/0/0.
[   91.224712] 
[   91.224712] stack backtrace:
[   91.228794] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W         5.10.0-rc4-next-20201119-00002-g51c2bf0ac853 #25
[   91.234877] Hardware name: linux,dummy-virt (DT)
[   91.239032] Call trace:
[   91.242587]  dump_backtrace+0x0/0x240
[   91.246500]  show_stack+0x34/0x88
[   91.250295]  dump_stack+0x140/0x1bc
[   91.254159]  lockdep_rcu_suspicious+0xe4/0xf8
[   91.258332]  trace_hardirqs_off+0x214/0x330

Quoted 8 lines

[   91.262462]  trace_graph_return+0x1ac/0x1d8
[   91.266564]  ftrace_return_to_handler+0xa4/0x170
[   91.270809]  return_to_handler+0x1c/0x38
[   91.274826]  default_idle_call+0x94/0x38c
[   91.278869]  do_idle+0x240/0x290
[   91.282633]  rest_init+0x1e8/0x2dc
[   91.286529]  arch_call_rest_init+0x1c/0x28
[   91.290585]  start_kernel+0x638/0x670

Quoted 4 lines

Hmm... I suspect that arch_cpu_idle() is being traced here, and I reckon we have to mark that and its callees as noinstr, since it doesn't seem sane to have ftrace check whether RCU is watching for every function call. Maybe Paul or Steve can correct me. ;)

Yes, it's arch_cpu_idle().

Quoted 7 lines

Quoted 4 lines
If you still have the binary lying around, can you check whether default_idle_call+0x94/0x38c is just after the call to arch_cpu_idle()? If you could dump the asm around that, along with whatever faddr2line tells you, that'd be a great help.
I reran to be sure, with similar results. I've attached a syz-symbolize'd version of the warnings.

Thanks for confirming, and for the symbolized report.

I'll see about getting this fixed ASAP.

Thanks,
Mark.

Marco Elver

author maintainer

2020-11-20 14:19 UTC #41 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

In reply to Paul E. McKenney

Quoted 43 lines · Paul E. McKenney

Quoted 2 lines · Marco Elver
Quoted 1 line · Paul E. McKenney
On Thu, Nov 19, 2020 at 06:02:59PM +0100, Marco Elver wrote:
[ . . . ]
Quoted 25 lines
Quoted 10 lines
Quoted 2 lines
I can try bisection again, or reverting some commits that might be suspicious? But we'd need some selection of suspicious commits.
The report claims that one of the rcu_node ->lock fields is held with interrupts enabled, which would indeed be bad. Except that all of the stack traces that it shows have these locks held within the scheduling-clock interrupt handler. Now with the "rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled" but without the "sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled" commit, I understand why. With both, I don't see how this happens.
I'm at a loss, but happy to keep bisecting and trying patches. I'm also considering:
Is it the compiler? Probably not, I tried 2 versions of GCC.
Can we trust lockdep to precisely know IRQ state? I know there's been some recent work around this, but hopefully we're not affected here?
Is QEMU buggy?
Quoted 3 lines
At this point, I am reduced to adding lockdep_assert_irqs_disabled() calls at various points in that code, as shown in the patch below.
Quoted 6 lines
Quoted 3 lines
At this point, I would guess that your first priority would be the initial bug rather than this following issue, but you never know, this might well help diagnose the initial bug.
I don't mind either way. I'm worried deadlocking the whole system might be worse.
Here is another set of lockdep_assert_irqs_disabled() calls on the off-chance that they actually find something.
Thanx, Paul

Quoted 7 lines

------------------------------------------------------------------------
commit bcca5277df3f24db15e15ccc8b05ecf346d05169
Author: Paul E. McKenney <[email protected]>
Date:   Thu Nov 19 13:30:33 2020 -0800
rcu: Add lockdep_assert_irqs_disabled() to raw_spin_unlock_rcu_node() macros

None of those triggered either.

I found that disabling ftrace for some of kernel/rcu (see below) solved the stalls (and any mention of deadlocks as a side-effect I assume), resulting in successful boot.

Does that provide any additional clues? I tried to narrow it down to 1-2 files, but that doesn't seem to work.

Thanks,
-- Marco

------ >8 ------

kernel/rcu/Makefile +7 -0

index 0cfb009a99b9..678b4b094f94 100644
@@ -3,6 +3,13 @@
 # and is generally not a function of system call inputs.
 KCOV_INSTRUMENT := n
 
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_update.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_sync.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_srcutree.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_tree.o = $(CC_FLAGS_FTRACE)
+endif
+
 ifeq ($(CONFIG_KCSAN),y)
 KBUILD_CFLAGS += -g -fno-omit-frame-pointer
 endif

Paul E. McKenney

maintainer

2020-11-20 14:39 UTC #42 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 52 lines · Marco Elver

Quoted 43 lines · Paul E. McKenney
Quoted 2 lines · Marco Elver
Quoted 1 line · Paul E. McKenney
On Thu, Nov 19, 2020 at 06:02:59PM +0100, Marco Elver wrote:
[ . . . ]
Quoted 25 lines
Quoted 10 lines
Quoted 2 lines
I can try bisection again, or reverting some commits that might be suspicious? But we'd need some selection of suspicious commits.
The report claims that one of the rcu_node ->lock fields is held with interrupts enabled, which would indeed be bad. Except that all of the stack traces that it shows have these locks held within the scheduling-clock interrupt handler. Now with the "rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled" but without the "sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled" commit, I understand why. With both, I don't see how this happens.
I'm at a loss, but happy to keep bisecting and trying patches. I'm also considering:
Is it the compiler? Probably not, I tried 2 versions of GCC.
Can we trust lockdep to precisely know IRQ state? I know there's been some recent work around this, but hopefully we're not affected here?
Is QEMU buggy?
Quoted 3 lines
At this point, I am reduced to adding lockdep_assert_irqs_disabled() calls at various points in that code, as shown in the patch below.
Quoted 6 lines
Quoted 3 lines
At this point, I would guess that your first priority would be the initial bug rather than this following issue, but you never know, this might well help diagnose the initial bug.
I don't mind either way. I'm worried deadlocking the whole system might be worse.
Here is another set of lockdep_assert_irqs_disabled() calls on the off-chance that they actually find something.
Thanx, Paul
Quoted 7 lines
------------------------------------------------------------------------
commit bcca5277df3f24db15e15ccc8b05ecf346d05169
Author: Paul E. McKenney <[email protected]>
Date:   Thu Nov 19 13:30:33 2020 -0800
rcu: Add lockdep_assert_irqs_disabled() to raw_spin_unlock_rcu_node() macros

Quoted 8 lines

None of those triggered either.
I found that disabling ftrace for some of kernel/rcu (see below) solved the stalls (and any mention of deadlocks as a side-effect I assume), resulting in successful boot.
Does that provide any additional clues? I tried to narrow it down to 1-2 files, but that doesn't seem to work.

There were similar issues during the x86/entry work. Are the ARM guys doing arm64/entry work now?

Thanx, Paul

Quoted 23 lines

Thanks,
-- Marco

------ >8 ------

kernel/rcu/Makefile +7 -0

index 0cfb009a99b9..678b4b094f94 100644
@@ -3,6 +3,13 @@
 # and is generally not a function of system call inputs.
 KCOV_INSTRUMENT := n
 
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_update.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_sync.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_srcutree.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_tree.o = $(CC_FLAGS_FTRACE)
+endif
+
 ifeq ($(CONFIG_KCSAN),y)
 KBUILD_CFLAGS += -g -fno-omit-frame-pointer
 endif

Mark Rutland

2020-11-20 15:22 UTC #43 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 10 lines · Paul E. McKenney

Quoted 6 lines · Marco Elver
I found that disabling ftrace for some of kernel/rcu (see below) solved the stalls (and any mention of deadlocks as a side-effect I assume), resulting in successful boot.
Does that provide any additional clues? I tried to narrow it down to 1-2 files, but that doesn't seem to work.
There were similar issues during the x86/entry work. Are the ARM guys doing arm64/entry work now?

I'm currently looking at it. I had been trying to shift things to C for a while, and right now I'm trying to fix the lockdep state tracking, which is requiring untangling lockdep/rcu/tracing.

The main issue I see remaining atm is that we don't save/restore the lockdep state over exceptions taken from kernel to kernel. That could result in lockdep thinking IRQs are disabled when they're actually enabled (because code in the nested context might do a save/restore while IRQs are disabled, then return to a context where IRQs are enabled), but AFAICT shouldn't result in the inverse in most cases since the non-NMI handlers all call lockdep_hardirqs_disabled().

I'm at a loss to explaim the rcu vs ftrace bits, so if you have any pointers to the issuies ween with the x86 rework that'd be quite handy.

Thanks,
Mark.

Quoted 26 lines

Thanx, Paul

Quoted 23 lines

Thanks,
-- Marco

------ >8 ------

kernel/rcu/Makefile +7 -0

index 0cfb009a99b9..678b4b094f94 100644
@@ -3,6 +3,13 @@
 # and is generally not a function of system call inputs.
 KCOV_INSTRUMENT := n
 
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_update.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_sync.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_srcutree.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_tree.o = $(CC_FLAGS_FTRACE)
+endif
+
 ifeq ($(CONFIG_KCSAN),y)
 KBUILD_CFLAGS += -g -fno-omit-frame-pointer
 endif

Paul E. McKenney

maintainer

2020-11-20 17:38 UTC #44 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 24 lines · Mark Rutland

Quoted 10 lines · Paul E. McKenney
Quoted 6 lines · Marco Elver
I found that disabling ftrace for some of kernel/rcu (see below) solved the stalls (and any mention of deadlocks as a side-effect I assume), resulting in successful boot.
Does that provide any additional clues? I tried to narrow it down to 1-2 files, but that doesn't seem to work.
There were similar issues during the x86/entry work. Are the ARM guys doing arm64/entry work now?
I'm currently looking at it. I had been trying to shift things to C for a while, and right now I'm trying to fix the lockdep state tracking, which is requiring untangling lockdep/rcu/tracing.
The main issue I see remaining atm is that we don't save/restore the lockdep state over exceptions taken from kernel to kernel. That could result in lockdep thinking IRQs are disabled when they're actually enabled (because code in the nested context might do a save/restore while IRQs are disabled, then return to a context where IRQs are enabled), but AFAICT shouldn't result in the inverse in most cases since the non-NMI handlers all call lockdep_hardirqs_disabled().

Quoted 2 lines

I'm at a loss to explaim the rcu vs ftrace bits, so if you have any pointers to the issuies ween with the x86 rework that'd be quite handy.

There were several over a number of months. I especially recall issues with the direct-from-idle execution of smp_call_function*() handlers, and also with some of the special cases in the entry code, for example, reentering the kernel from the kernel. This latter could cause RCU to not be watching when it should have been or vice versa.

I would of course be most aware of the issues that impinged on RCU and that were located by rcutorture. This is actually not hard to run, especially if the ARM bits in the scripting have managed to avoid bitrot. The "modprobe rcutorture" approach has fewer dependencies. Either way:
https://paulmck.livejournal.com/57769.html and later posts.

Thanx, Paul

Quoted 29 lines

Thanks,
Mark.

Quoted 26 lines

Thanx, Paul

Quoted 23 lines

Thanks,
-- Marco

------ >8 ------

kernel/rcu/Makefile +7 -0

index 0cfb009a99b9..678b4b094f94 100644
@@ -3,6 +3,13 @@
 # and is generally not a function of system call inputs.
 KCOV_INSTRUMENT := n
 
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_update.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_sync.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_srcutree.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_tree.o = $(CC_FLAGS_FTRACE)
+endif
+
 ifeq ($(CONFIG_KCSAN),y)
 KBUILD_CFLAGS += -g -fno-omit-frame-pointer
 endif

Mark Rutland

2020-11-20 18:02 UTC #45 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 25 lines · Paul E. McKenney

Quoted 24 lines · Mark Rutland
Quoted 10 lines · Paul E. McKenney
Quoted 6 lines · Marco Elver
I found that disabling ftrace for some of kernel/rcu (see below) solved the stalls (and any mention of deadlocks as a side-effect I assume), resulting in successful boot.
Does that provide any additional clues? I tried to narrow it down to 1-2 files, but that doesn't seem to work.
There were similar issues during the x86/entry work. Are the ARM guys doing arm64/entry work now?
I'm currently looking at it. I had been trying to shift things to C for a while, and right now I'm trying to fix the lockdep state tracking, which is requiring untangling lockdep/rcu/tracing.
The main issue I see remaining atm is that we don't save/restore the lockdep state over exceptions taken from kernel to kernel. That could result in lockdep thinking IRQs are disabled when they're actually enabled (because code in the nested context might do a save/restore while IRQs are disabled, then return to a context where IRQs are enabled), but AFAICT shouldn't result in the inverse in most cases since the non-NMI handlers all call lockdep_hardirqs_disabled().

Quoted 8 lines

Quoted 2 lines
I'm at a loss to explaim the rcu vs ftrace bits, so if you have any pointers to the issuies ween with the x86 rework that'd be quite handy.
There were several over a number of months. I especially recall issues with the direct-from-idle execution of smp_call_function*() handlers, and also with some of the special cases in the entry code, for example, reentering the kernel from the kernel. This latter could cause RCU to not be watching when it should have been or vice versa.

Ah; those are precisely the cases I'm currently fixing, so if we're lucky this is an indirect result of one of those rather than a novel source of pain...

Quoted 5 lines

I would of course be most aware of the issues that impinged on RCU and that were located by rcutorture. This is actually not hard to run, especially if the ARM bits in the scripting have managed to avoid bitrot. The "modprobe rcutorture" approach has fewer dependencies. Either way:
https://paulmck.livejournal.com/57769.html and later posts.

That is a very good idea. I'd been relying on Syzkaller to tickle the issue, but the torture infrastructure is a much better fit for this problem. I hadn't realise how comprehensive the scripting was, thanks for this!

I'll see about giving that a go once I have the irq-from-idle cases sorted, as those are very obviously broken if you hack trace_hardirqs_{on,off}() to check that RCU is watching.

Thanks,
Mark.

Paul E. McKenney

maintainer

2020-11-20 18:58 UTC #46 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 35 lines · Mark Rutland

Quoted 25 lines · Paul E. McKenney
Quoted 24 lines · Mark Rutland
Quoted 10 lines · Paul E. McKenney
Quoted 6 lines · Marco Elver
I found that disabling ftrace for some of kernel/rcu (see below) solved the stalls (and any mention of deadlocks as a side-effect I assume), resulting in successful boot.
Does that provide any additional clues? I tried to narrow it down to 1-2 files, but that doesn't seem to work.
There were similar issues during the x86/entry work. Are the ARM guys doing arm64/entry work now?
I'm currently looking at it. I had been trying to shift things to C for a while, and right now I'm trying to fix the lockdep state tracking, which is requiring untangling lockdep/rcu/tracing.
The main issue I see remaining atm is that we don't save/restore the lockdep state over exceptions taken from kernel to kernel. That could result in lockdep thinking IRQs are disabled when they're actually enabled (because code in the nested context might do a save/restore while IRQs are disabled, then return to a context where IRQs are enabled), but AFAICT shouldn't result in the inverse in most cases since the non-NMI handlers all call lockdep_hardirqs_disabled().
Quoted 8 lines
Quoted 2 lines
I'm at a loss to explaim the rcu vs ftrace bits, so if you have any pointers to the issuies ween with the x86 rework that'd be quite handy.
There were several over a number of months. I especially recall issues with the direct-from-idle execution of smp_call_function*() handlers, and also with some of the special cases in the entry code, for example, reentering the kernel from the kernel. This latter could cause RCU to not be watching when it should have been or vice versa.

Quoted 3 lines

Ah; those are precisely the cases I'm currently fixing, so if we're lucky this is an indirect result of one of those rather than a novel source of pain...

Here is hoping!

Quoted 10 lines

Quoted 5 lines
I would of course be most aware of the issues that impinged on RCU and that were located by rcutorture. This is actually not hard to run, especially if the ARM bits in the scripting have managed to avoid bitrot. The "modprobe rcutorture" approach has fewer dependencies. Either way:
https://paulmck.livejournal.com/57769.html and later posts.
That is a very good idea. I'd been relying on Syzkaller to tickle the issue, but the torture infrastructure is a much better fit for this problem. I hadn't realise how comprehensive the scripting was, thanks for this!

But why not both rcutorture and Syzkaller? ;-)

Quoted 3 lines

I'll see about giving that a go once I have the irq-from-idle cases sorted, as those are very obviously broken if you hack trace_hardirqs_{on,off}() to check that RCU is watching.

Sounds good!

Thanx, Paul

Steven Rostedt

maintainer

2020-11-20 15:26 UTC #47 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

In reply to Marco Elver

Quoted 19 lines · On Fri, 20 Nov 2020 15:19:28 +0100 Marco Elver <[email protected]> wrote:

None of those triggered either.
I found that disabling ftrace for some of kernel/rcu (see below) solved the stalls (and any mention of deadlocks as a side-effect I assume), resulting in successful boot.
Does that provide any additional clues? I tried to narrow it down to 1-2 files, but that doesn't seem to work.
Thanks,
-- Marco
------ >8 ------
kernel/rcu/Makefile +0 -0
index 0cfb009a99b9..678b4b094f94 100644

kernel/rcu/Makefile line 12

Quoted 10 lines

kernel/rcu/Makefile +7 -0

@@ -3,6 +3,13 @@
 # and is generally not a function of system call inputs.
 KCOV_INSTRUMENT := n
 
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_update.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_sync.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_srcutree.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_tree.o = $(CC_FLAGS_FTRACE)
+endif
+

Can you narrow it down further? That is, do you really need all of the above to stop the stalls?

Also, since you are using linux-next, you have ftrace recursion debugging. Please enable:

CONFIG_FTRACE_RECORD_RECURSION=y
CONFIG_RING_BUFFER_RECORD_RECURSION=y

when enabling any of the above. If you can get to a successful boot, you can then:

 # cat /sys/kernel/tracing/recursed_functions

Which would let me know if there's an recursion issue in RCU somewhere.

-- Steve

Marco Elver

author maintainer

2020-11-20 18:17 UTC #48 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 25 lines · Steven Rostedt

Quoted 22 lines · On Fri, 20 Nov 2020 15:19:28 +0100 Marco Elver <[email protected]> wrote:
None of those triggered either.
I found that disabling ftrace for some of kernel/rcu (see below) solved the stalls (and any mention of deadlocks as a side-effect I assume), resulting in successful boot.
Does that provide any additional clues? I tried to narrow it down to 1-2 files, but that doesn't seem to work.
Thanks,
-- Marco
------ >8 ------
kernel/rcu/Makefile +0 -0
index 0cfb009a99b9..678b4b094f94 100644
@@ -3,6 +3,13 @@
 # and is generally not a function of system call inputs.
 KCOV_INSTRUMENT := n
 

Quoted 10 lines

kernel/rcu/Makefile line 12
Quoted 7 lines
kernel/rcu/Makefile +7 -0
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_update.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_sync.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_srcutree.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_tree.o = $(CC_FLAGS_FTRACE)
+endif
+
Can you narrow it down further? That is, do you really need all of the above to stop the stalls?

I tried to reduce it to 1 or combinations of 2 files only, but that didn't work.

Quoted 6 lines

Also, since you are using linux-next, you have ftrace recursion debugging. Please enable:
CONFIG_FTRACE_RECORD_RECURSION=y
CONFIG_RING_BUFFER_RECORD_RECURSION=y

Quoted 6 lines

when enabling any of the above. If you can get to a successful boot, you can then:
 # cat /sys/kernel/tracing/recursed_functions
Which would let me know if there's an recursion issue in RCU somewhere.

To get the system to boot in the first place (as mentioned in other emails) I again needed to revert
"rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled",
as otherwise would run into the deadlock. That used to still result in stall warnings, except when ftrace's recursion detection is on it seems.

With that, this is what I get:

| # cat /sys/kernel/tracing/recursed_functions
| trace_selftest_test_recursion_func+0x34/0x48:   trace_selftest_dynamic_test_func+0x4/0x28
| el1_irq+0xc0/0x180:     gic_handle_irq+0x4/0x108
| gic_handle_irq+0x70/0x108:      __handle_domain_irq+0x4/0x130
| __handle_domain_irq+0x7c/0x130: irq_enter+0x4/0x28
| trace_rcu_dyntick+0x168/0x190:  rcu_read_lock_sched_held+0x4/0x98
| rcu_read_lock_sched_held+0x30/0x98:     rcu_read_lock_held_common+0x4/0x88
| rcu_read_lock_held_common+0x50/0x88:    rcu_lockdep_current_cpu_online+0x4/0xd0
| irq_enter+0x1c/0x28:    irq_enter_rcu+0x4/0xa8
| irq_enter_rcu+0x3c/0xa8:        irqtime_account_irq+0x4/0x198
| irq_enter_rcu+0x44/0xa8:        preempt_count_add+0x4/0x1a0
| trace_hardirqs_off+0x254/0x2d8: __srcu_read_lock+0x4/0xa0
| trace_hardirqs_off+0x25c/0x2d8: rcu_irq_enter_irqson+0x4/0x78
| trace_rcu_dyntick+0xd8/0x190:   __traceiter_rcu_dyntick+0x4/0x80
| trace_hardirqs_off+0x294/0x2d8: rcu_irq_exit_irqson+0x4/0x78
| trace_hardirqs_off+0x2a0/0x2d8: __srcu_read_unlock+0x4/0x88

Thanks,
-- Marco

Steven Rostedt

maintainer

2020-11-20 18:57 UTC #49 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 8 lines · On Fri, 20 Nov 2020 19:17:37 +0100 Marco Elver <[email protected]> wrote:

| # cat /sys/kernel/tracing/recursed_functions
| trace_selftest_test_recursion_func+0x34/0x48:   trace_selftest_dynamic_test_func+0x4/0x28
| el1_irq+0xc0/0x180:     gic_handle_irq+0x4/0x108
| gic_handle_irq+0x70/0x108:      __handle_domain_irq+0x4/0x130
| __handle_domain_irq+0x7c/0x130: irq_enter+0x4/0x28
| trace_rcu_dyntick+0x168/0x190:  rcu_read_lock_sched_held+0x4/0x98
| rcu_read_lock_sched_held+0x30/0x98:     rcu_read_lock_held_common+0x4/0x88
| rcu_read_lock_held_common+0x50/0x88:    rcu_lockdep_current_cpu_online+0x4/0xd0

Quoted 8 lines

| irq_enter+0x1c/0x28:    irq_enter_rcu+0x4/0xa8
| irq_enter_rcu+0x3c/0xa8:        irqtime_account_irq+0x4/0x198
| irq_enter_rcu+0x44/0xa8:        preempt_count_add+0x4/0x1a0
| trace_hardirqs_off+0x254/0x2d8: __srcu_read_lock+0x4/0xa0
| trace_hardirqs_off+0x25c/0x2d8: rcu_irq_enter_irqson+0x4/0x78
| trace_rcu_dyntick+0xd8/0x190:   __traceiter_rcu_dyntick+0x4/0x80
| trace_hardirqs_off+0x294/0x2d8: rcu_irq_exit_irqson+0x4/0x78
| trace_hardirqs_off+0x2a0/0x2d8: __srcu_read_unlock+0x4/0x88

These look normal. They happen when an interrupt occurs while tracing something with interrupts enabled, and the interrupt traces a function before it sets the "preempt_count" to reflect that its in a new context.

That is:

	normal_context:
		func_A();
			trace_function();
				<interrupt>
					irq_enter();
						trace_function()
							if (int_interrupt())
							 [returns false]

					set_preempt_count (in interrupt)

And the recursion detection is tricked into thinking it recursed in the same context. The lastest code handles this by allowing one level of recursion:

https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=b02414c8f045ab3b9afc816c3735bc98c5c3d262

-- Steve

Steven Rostedt

maintainer

2020-11-20 19:16 UTC #50 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

In reply to Marco Elver

Quoted 16 lines · On Fri, 20 Nov 2020 19:17:37 +0100 Marco Elver <[email protected]> wrote:

Quoted 5 lines
Quoted 5 lines
+++ b/kernel/rcu/Makefile
(quoted diff) +0 -0
@@ -3,6 +3,13 @@
 # and is generally not a function of system call inputs.
 KCOV_INSTRUMENT := n
 
Quoted 10 lines
Review line 12
Quoted 7 lines
(quoted diff) +7 -0
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_update.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_sync.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_srcutree.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_tree.o = $(CC_FLAGS_FTRACE)
+endif
+  
Can you narrow it down further? That is, do you really need all of the above to stop the stalls?

Quoted 2 lines

I tried to reduce it to 1 or combinations of 2 files only, but that didn't work.

I'm curious if this would help at all?

kernel/rcu/tree.c +1 -1

index 2a52f42f64b6..d020ecefd151 100644
@@ -1094,7 +1094,7 @@ static void rcu_disable_urgency_upon_qs(struct rcu_data *rdp)
  * if the current CPU is not in its idle loop or is in an interrupt or
  * NMI handler, return true.
  */
-bool rcu_is_watching(void)
+notrace bool rcu_is_watching(void)
 {
 	bool ret;

Although I don't see it in the recursion list.

-- Steve

Marco Elver

author maintainer

2020-11-20 19:22 UTC #51 lore raw

Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)

Quoted 39 lines · Steven Rostedt

Quoted 16 lines · On Fri, 20 Nov 2020 19:17:37 +0100 Marco Elver <[email protected]> wrote:
Quoted 5 lines
Quoted 5 lines
+++ b/kernel/rcu/Makefile
(quoted diff) +0 -0
@@ -3,6 +3,13 @@
 # and is generally not a function of system call inputs.
 KCOV_INSTRUMENT := n
 
Quoted 10 lines
Review line 12
Quoted 7 lines
(quoted diff) +7 -0
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_update.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_sync.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_srcutree.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_tree.o = $(CC_FLAGS_FTRACE)
+endif
+
Can you narrow it down further? That is, do you really need all of the above to stop the stalls?
Quoted 2 lines
I tried to reduce it to 1 or combinations of 2 files only, but that didn't work.
I'm curious if this would help at all?
kernel/rcu/tree.c +1 -1
index 2a52f42f64b6..d020ecefd151 100644
@@ -1094,7 +1094,7 @@ static void rcu_disable_urgency_upon_qs(struct rcu_data *rdp)
  * if the current CPU is not in its idle loop or is in an interrupt or
  * NMI handler, return true.
  */
-bool rcu_is_watching(void)
+notrace bool rcu_is_watching(void)
 {
        bool ret;
 

Quoted 1 line

Although I don't see it in the recursion list.

It seems a patch to that effect is already in -next ("rcu,ftrace: Fix ftrace recursion"), and my experiments so far have all been with it.

Thanks,
-- Marco

Steven Rostedt

maintainer

2020-11-20 19:27 UTC #52 lore raw

In reply to Marco Elver

Quoted 4 lines · On Thu, 19 Nov 2020 13:53:57 +0100 Marco Elver <[email protected]> wrote:

Running tests again, along with the function tracer Running tests on all trace events:
Testing all events:
BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 12s!

The below patch might be noisy, but can you add it to the kernel that crashes and see if a particular event causes the issue?

[ note I didn't even compile test. I hope it works ;) ]

Perhaps run it a couple of times to see if it crashes on the same set of events each time.

-- Steve

kernel/trace/trace_events.c +6 -0

index 98d194d8460e..eb1dd9cf77a9 100644
@@ -773,6 +773,8 @@ static void remove_event_file_dir(struct trace_event_file *file)
 	kmem_cache_free(file_cachep, file);
 }
 
+static int spam;
+
 /*
  * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
  */

@@ -808,6 +810,8 @@ __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
 		if (event && strcmp(event, name) != 0)
 			continue;
 
+		if (spam)
+			printk("%s event %s\n", set ? "enabling" : "disabling", name);
 		ret = ftrace_event_enable_disable(file, set);
 
 		/*

@@ -3647,6 +3651,7 @@ static __init void event_trace_self_tests(void)
 	pr_info("Running tests on all trace events:\n");
 	pr_info("Testing all events: ");
 
+	spam = 1;
 	ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
 	if (WARN_ON_ONCE(ret)) {
 		pr_warn("error enabling all events\n");

@@ -3661,6 +3666,7 @@ static __init void event_trace_self_tests(void)
 		pr_warn("error disabling all events\n");
 		return;
 	}
+	spam = 0;
 
 	pr_cont("OK\n");
 }

Marco Elver

author maintainer

2020-11-23 15:27 UTC #53 lore raw

Quoted 8 lines · Steven Rostedt

Quoted 4 lines · On Thu, 19 Nov 2020 13:53:57 +0100 Marco Elver <[email protected]> wrote:
Running tests again, along with the function tracer Running tests on all trace events:
Testing all events:
BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 12s!

Quoted 7 lines

The below patch might be noisy, but can you add it to the kernel that crashes and see if a particular event causes the issue?
[ note I didn't even compile test. I hope it works ;) ]
Perhaps run it a couple of times to see if it crashes on the same set of events each time.

Thanks! I have attached the logs of 2 runs. I think one problem here is that the enabling of an event doesn't immediately trigger the problem, so it's hard to say which one caused it.

Thanks,
-- Marco

Steven Rostedt

maintainer

2020-11-23 16:28 UTC #54 lore raw

Quoted 12 lines · On Mon, 23 Nov 2020 16:27:20 +0100 Marco Elver <[email protected]> wrote:

Quoted 11 lines · Steven Rostedt
Quoted 4 lines · On Thu, 19 Nov 2020 13:53:57 +0100 Marco Elver <[email protected]> wrote:
Running tests again, along with the function tracer Running tests on all trace events:
Testing all events:
BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 12s!  
The below patch might be noisy, but can you add it to the kernel that crashes and see if a particular event causes the issue?

Quoted 9 lines

Quoted 4 lines
[ note I didn't even compile test. I hope it works ;) ]
Perhaps run it a couple of times to see if it crashes on the same set of events each time.
Thanks! I have attached the logs of 2 runs. I think one problem here is that the enabling of an event doesn't immediately trigger the problem, so it's hard to say which one caused it.

I noticed:

[  237.650900] enabling event benchmark_event

In both traces. Could you disable CONFIG_TRACEPOINT_BENCHMARK and see if the issue goes away. That event kicks off a thread that spins in a tight loop for some time and could possibly cause some issues.

It still shouldn't break things, we can narrow it down if it is the culprit.

-- Steve

Steven Rostedt

maintainer

2020-11-23 16:37 UTC #55 lore raw

Quoted 10 lines · On Mon, 23 Nov 2020 11:28:12 -0500 Steven Rostedt <[email protected]> wrote:

I noticed:
[  237.650900] enabling event benchmark_event
In both traces. Could you disable CONFIG_TRACEPOINT_BENCHMARK and see if the issue goes away. That event kicks off a thread that spins in a tight loop for some time and could possibly cause some issues.
It still shouldn't break things, we can narrow it down if it is the culprit.

And it probably is the issue because that thread will never sleep! It runs a loop of:

static int benchmark_event_kthread(void *arg)

{
	/* sleep a bit to make sure the tracepoint gets activated */
	msleep(100);

	while (!kthread_should_stop()) {

		trace_do_benchmark();

		/*
		 * We don't go to sleep, but let others run as well.
		 * This is basically a "yield()" to let any task that
		 * wants to run, schedule in, but if the CPU is idle,
		 * we'll keep burning cycles.
		 *
		 * Note the tasks_rcu_qs() version of cond_resched() will
		 * notify synchronize_rcu_tasks() that this thread has
		 * passed a quiescent state for rcu_tasks. Otherwise
		 * this thread will never voluntarily schedule which would
		 * block synchronize_rcu_tasks() indefinitely.
		 */
		cond_resched_tasks_rcu_qs();
	}

	return 0;
}

Did something change, where that "cond_resched_tasks_rcu_qs()" doesn't let things progress on ARM64?

I noticed that you have PREEMPT enabled so this will only be preempted when its schedule time runs out and something else wants to run. How would that affect other threads?

-- Steve