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5.12-rc1 regression: freezing iou-mgr/wrk failed

DISCUSSION Alex Xu (Hello71) 2 participants 6 messages Mar 2, 2021 1 message not in the archive

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Alex Xu (Hello71)

author
#1 lore raw

Hi,

On Linux 5.12-rc1, I am unable to suspend to RAM. The system freezes for about 40 seconds and then continues operation. The following messages are printed to the kernel log:

[  240.650300] PM: suspend entry (deep)
[  240.650748] Filesystems sync: 0.000 seconds
[  240.725605] Freezing user space processes ...
[  260.739483] Freezing of tasks failed after 20.013 seconds (3 tasks refusing to freeze, wq_busy=0):
[  260.739497] task:iou-mgr-446     state:S stack:    0 pid:  516 ppid:   439 flags:0x00004224
[  260.739504] Call Trace:
[  260.739507]  ? sysvec_apic_timer_interrupt+0xb/0x81
[  260.739515]  ? pick_next_task_fair+0x197/0x1cde
[  260.739519]  ? sysvec_reschedule_ipi+0x2f/0x6a
[  260.739522]  ? asm_sysvec_reschedule_ipi+0x12/0x20
[  260.739525]  ? __schedule+0x57/0x6d6
[  260.739529]  ? del_timer_sync+0xb9/0x115
[  260.739533]  ? schedule+0x63/0xd5
[  260.739536]  ? schedule_timeout+0x219/0x356
[  260.739540]  ? __next_timer_interrupt+0xf1/0xf1
[  260.739544]  ? io_wq_manager+0x73/0xb1
[  260.739549]  ? io_wq_create+0x262/0x262
[  260.739553]  ? ret_from_fork+0x22/0x30
[  260.739557] task:iou-mgr-517     state:S stack:    0 pid:  522 ppid:   439 flags:0x00004224
[  260.739561] Call Trace:
[  260.739563]  ? sysvec_apic_timer_interrupt+0xb/0x81
[  260.739566]  ? pick_next_task_fair+0x16f/0x1cde
[  260.739569]  ? sysvec_apic_timer_interrupt+0xb/0x81
[  260.739571]  ? asm_sysvec_apic_timer_interrupt+0x12/0x20
[  260.739574]  ? __schedule+0x5b7/0x6d6
[  260.739578]  ? del_timer_sync+0x70/0x115
[  260.739581]  ? schedule_timeout+0x211/0x356
[  260.739585]  ? __next_timer_interrupt+0xf1/0xf1
[  260.739588]  ? io_wq_check_workers+0x15/0x11f
[  260.739592]  ? io_wq_manager+0x69/0xb1
[  260.739596]  ? io_wq_create+0x262/0x262
[  260.739600]  ? ret_from_fork+0x22/0x30
[  260.739603] task:iou-wrk-517     state:S stack:    0 pid:  523 ppid:   439 flags:0x00004224
[  260.739607] Call Trace:
[  260.739609]  ? __schedule+0x5b7/0x6d6
[  260.739614]  ? schedule+0x63/0xd5
[  260.739617]  ? schedule_timeout+0x219/0x356
[  260.739621]  ? __next_timer_interrupt+0xf1/0xf1
[  260.739624]  ? task_thread.isra.0+0x148/0x3af
[  260.739628]  ? task_thread_unbound+0xa/0xa
[  260.739632]  ? task_thread_bound+0x7/0x7
[  260.739636]  ? ret_from_fork+0x22/0x30
[  260.739647] OOM killer enabled.
[  260.739648] Restarting tasks ... done.
[  260.740077] PM: suspend exit

and then a set of similar messages except with s2idle instead of deep.

Reverting 5695e51619 ("Merge tag 'io_uring-worker.v3-2021-02-25' of
git://git.kernel.dk/linux-block") appears to resolve the issue. I have not yet bisected further. Let me know which troubleshooting steps I should perform next.

Thanks,
Alex.

maintainer
#2 lore raw
Quoted 52 lines · On 3/1/21 5:57 PM, Alex Xu (Hello71) wrote:

Hi,

On Linux 5.12-rc1, I am unable to suspend to RAM. The system freezes for about 40 seconds and then continues operation. The following messages are printed to the kernel log:

[  240.650300] PM: suspend entry (deep)
[  240.650748] Filesystems sync: 0.000 seconds
[  240.725605] Freezing user space processes ...
[  260.739483] Freezing of tasks failed after 20.013 seconds (3 tasks refusing to freeze, wq_busy=0):
[  260.739497] task:iou-mgr-446     state:S stack:    0 pid:  516 ppid:   439 flags:0x00004224
[  260.739504] Call Trace:
[  260.739507]  ? sysvec_apic_timer_interrupt+0xb/0x81
[  260.739515]  ? pick_next_task_fair+0x197/0x1cde
[  260.739519]  ? sysvec_reschedule_ipi+0x2f/0x6a
[  260.739522]  ? asm_sysvec_reschedule_ipi+0x12/0x20
[  260.739525]  ? __schedule+0x57/0x6d6
[  260.739529]  ? del_timer_sync+0xb9/0x115
[  260.739533]  ? schedule+0x63/0xd5
[  260.739536]  ? schedule_timeout+0x219/0x356
[  260.739540]  ? __next_timer_interrupt+0xf1/0xf1
[  260.739544]  ? io_wq_manager+0x73/0xb1
[  260.739549]  ? io_wq_create+0x262/0x262
[  260.739553]  ? ret_from_fork+0x22/0x30
[  260.739557] task:iou-mgr-517     state:S stack:    0 pid:  522 ppid:   439 flags:0x00004224
[  260.739561] Call Trace:
[  260.739563]  ? sysvec_apic_timer_interrupt+0xb/0x81
[  260.739566]  ? pick_next_task_fair+0x16f/0x1cde
[  260.739569]  ? sysvec_apic_timer_interrupt+0xb/0x81
[  260.739571]  ? asm_sysvec_apic_timer_interrupt+0x12/0x20
[  260.739574]  ? __schedule+0x5b7/0x6d6
[  260.739578]  ? del_timer_sync+0x70/0x115
[  260.739581]  ? schedule_timeout+0x211/0x356
[  260.739585]  ? __next_timer_interrupt+0xf1/0xf1
[  260.739588]  ? io_wq_check_workers+0x15/0x11f
[  260.739592]  ? io_wq_manager+0x69/0xb1
[  260.739596]  ? io_wq_create+0x262/0x262
[  260.739600]  ? ret_from_fork+0x22/0x30
[  260.739603] task:iou-wrk-517     state:S stack:    0 pid:  523 ppid:   439 flags:0x00004224
[  260.739607] Call Trace:
[  260.739609]  ? __schedule+0x5b7/0x6d6
[  260.739614]  ? schedule+0x63/0xd5
[  260.739617]  ? schedule_timeout+0x219/0x356
[  260.739621]  ? __next_timer_interrupt+0xf1/0xf1
[  260.739624]  ? task_thread.isra.0+0x148/0x3af
[  260.739628]  ? task_thread_unbound+0xa/0xa
[  260.739632]  ? task_thread_bound+0x7/0x7
[  260.739636]  ? ret_from_fork+0x22/0x30
[  260.739647] OOM killer enabled.
[  260.739648] Restarting tasks ... done.
[  260.740077] PM: suspend exit
Quoted 6 lines

and then a set of similar messages except with s2idle instead of deep.

Reverting 5695e51619 ("Merge tag 'io_uring-worker.v3-2021-02-25' of
git://git.kernel.dk/linux-block") appears to resolve the issue. I have not yet bisected further. Let me know which troubleshooting steps I should perform next.

Can you try and pull in:

git://git.kernel.dk/linux-block io_uring-5.12

and see if that resolves it? I usually always run -git on my laptop as well, but something broke it in the merge window so I need to figure out what that is first...

What distro are you running?

Signature · 1 line
Jens Axboe
maintainer
#3 lore raw
Quoted 62 lines · Jens Axboe
Quoted 52 lines · On 3/1/21 5:57 PM, Alex Xu (Hello71) wrote:

Hi,

On Linux 5.12-rc1, I am unable to suspend to RAM. The system freezes for about 40 seconds and then continues operation. The following messages are printed to the kernel log:

[  240.650300] PM: suspend entry (deep)
[  240.650748] Filesystems sync: 0.000 seconds
[  240.725605] Freezing user space processes ...
[  260.739483] Freezing of tasks failed after 20.013 seconds (3 tasks refusing to freeze, wq_busy=0):
[  260.739497] task:iou-mgr-446     state:S stack:    0 pid:  516 ppid:   439 flags:0x00004224
[  260.739504] Call Trace:
[  260.739507]  ? sysvec_apic_timer_interrupt+0xb/0x81
[  260.739515]  ? pick_next_task_fair+0x197/0x1cde
[  260.739519]  ? sysvec_reschedule_ipi+0x2f/0x6a
[  260.739522]  ? asm_sysvec_reschedule_ipi+0x12/0x20
[  260.739525]  ? __schedule+0x57/0x6d6
[  260.739529]  ? del_timer_sync+0xb9/0x115
[  260.739533]  ? schedule+0x63/0xd5
[  260.739536]  ? schedule_timeout+0x219/0x356
[  260.739540]  ? __next_timer_interrupt+0xf1/0xf1
[  260.739544]  ? io_wq_manager+0x73/0xb1
[  260.739549]  ? io_wq_create+0x262/0x262
[  260.739553]  ? ret_from_fork+0x22/0x30
[  260.739557] task:iou-mgr-517     state:S stack:    0 pid:  522 ppid:   439 flags:0x00004224
[  260.739561] Call Trace:
[  260.739563]  ? sysvec_apic_timer_interrupt+0xb/0x81
[  260.739566]  ? pick_next_task_fair+0x16f/0x1cde
[  260.739569]  ? sysvec_apic_timer_interrupt+0xb/0x81
[  260.739571]  ? asm_sysvec_apic_timer_interrupt+0x12/0x20
[  260.739574]  ? __schedule+0x5b7/0x6d6
[  260.739578]  ? del_timer_sync+0x70/0x115
[  260.739581]  ? schedule_timeout+0x211/0x356
[  260.739585]  ? __next_timer_interrupt+0xf1/0xf1
[  260.739588]  ? io_wq_check_workers+0x15/0x11f
[  260.739592]  ? io_wq_manager+0x69/0xb1
[  260.739596]  ? io_wq_create+0x262/0x262
[  260.739600]  ? ret_from_fork+0x22/0x30
[  260.739603] task:iou-wrk-517     state:S stack:    0 pid:  523 ppid:   439 flags:0x00004224
[  260.739607] Call Trace:
[  260.739609]  ? __schedule+0x5b7/0x6d6
[  260.739614]  ? schedule+0x63/0xd5
[  260.739617]  ? schedule_timeout+0x219/0x356
[  260.739621]  ? __next_timer_interrupt+0xf1/0xf1
[  260.739624]  ? task_thread.isra.0+0x148/0x3af
[  260.739628]  ? task_thread_unbound+0xa/0xa
[  260.739632]  ? task_thread_bound+0x7/0x7
[  260.739636]  ? ret_from_fork+0x22/0x30
[  260.739647] OOM killer enabled.
[  260.739648] Restarting tasks ... done.
[  260.740077] PM: suspend exit
Quoted 6 lines

and then a set of similar messages except with s2idle instead of deep.

Reverting 5695e51619 ("Merge tag 'io_uring-worker.v3-2021-02-25' of
git://git.kernel.dk/linux-block") appears to resolve the issue. I have not yet bisected further. Let me know which troubleshooting steps I should perform next.

Can you try and pull in:

Quoted 7 lines

git://git.kernel.dk/linux-block io_uring-5.12

and see if that resolves it? I usually always run -git on my laptop as well, but something broke it in the merge window so I need to figure out what that is first...

What distro are you running?

You probably want this on top...

fs/io-wq.c +2 -2
index 1fdb2b621b51..a763e1b09073 100644
@@ -567,7 +567,7 @@ static int task_thread(void *data, int index)
 	worker->task = current;
 
 	set_cpus_allowed_ptr(current, cpumask_of_node(wqe->node));
-	current->flags |= PF_NO_SETAFFINITY;
+	current->flags |= PF_NO_SETAFFINITY | PF_NOFREEZE;
 
 	raw_spin_lock_irq(&wqe->lock);
 	hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);

@@ -722,7 +722,7 @@ static int io_wq_manager(void *data)
 
 	sprintf(buf, "iou-mgr-%d", wq->task_pid);
 	set_task_comm(current, buf);
-	current->flags |= PF_IO_WORKER;
+	current->flags |= PF_IO_WORKER | PF_NOFREEZE;
 	wq->manager = get_task_struct(current);
 
 	complete(&wq->started);
fs/io_uring.c +1 -0
index 2757675ab417..e7aaf56b4dea 100644
@@ -6679,6 +6685,7 @@ static int io_sq_thread(void *data)
 	set_task_comm(current, buf);
 	sqd->thread = current;
 	current->pf_io_worker = NULL;
+	current->flags |= PF_NOFREEZE;
 
 	if (sqd->sq_cpu != -1)
 		set_cpus_allowed_ptr(current, cpumask_of(sqd->sq_cpu));
Signature · 1 line
Jens Axboe
maintainer
#4 lore raw
Quoted 65 lines · Jens Axboe
Quoted 64 lines · Jens Axboe
Quoted 52 lines · On 3/1/21 5:57 PM, Alex Xu (Hello71) wrote:

Hi,

On Linux 5.12-rc1, I am unable to suspend to RAM. The system freezes for about 40 seconds and then continues operation. The following messages are printed to the kernel log:

[  240.650300] PM: suspend entry (deep)
[  240.650748] Filesystems sync: 0.000 seconds
[  240.725605] Freezing user space processes ...
[  260.739483] Freezing of tasks failed after 20.013 seconds (3 tasks refusing to freeze, wq_busy=0):
[  260.739497] task:iou-mgr-446     state:S stack:    0 pid:  516 ppid:   439 flags:0x00004224
[  260.739504] Call Trace:
[  260.739507]  ? sysvec_apic_timer_interrupt+0xb/0x81
[  260.739515]  ? pick_next_task_fair+0x197/0x1cde
[  260.739519]  ? sysvec_reschedule_ipi+0x2f/0x6a
[  260.739522]  ? asm_sysvec_reschedule_ipi+0x12/0x20
[  260.739525]  ? __schedule+0x57/0x6d6
[  260.739529]  ? del_timer_sync+0xb9/0x115
[  260.739533]  ? schedule+0x63/0xd5
[  260.739536]  ? schedule_timeout+0x219/0x356
[  260.739540]  ? __next_timer_interrupt+0xf1/0xf1
[  260.739544]  ? io_wq_manager+0x73/0xb1
[  260.739549]  ? io_wq_create+0x262/0x262
[  260.739553]  ? ret_from_fork+0x22/0x30
[  260.739557] task:iou-mgr-517     state:S stack:    0 pid:  522 ppid:   439 flags:0x00004224
[  260.739561] Call Trace:
[  260.739563]  ? sysvec_apic_timer_interrupt+0xb/0x81
[  260.739566]  ? pick_next_task_fair+0x16f/0x1cde
[  260.739569]  ? sysvec_apic_timer_interrupt+0xb/0x81
[  260.739571]  ? asm_sysvec_apic_timer_interrupt+0x12/0x20
[  260.739574]  ? __schedule+0x5b7/0x6d6
[  260.739578]  ? del_timer_sync+0x70/0x115
[  260.739581]  ? schedule_timeout+0x211/0x356
[  260.739585]  ? __next_timer_interrupt+0xf1/0xf1
[  260.739588]  ? io_wq_check_workers+0x15/0x11f
[  260.739592]  ? io_wq_manager+0x69/0xb1
[  260.739596]  ? io_wq_create+0x262/0x262
[  260.739600]  ? ret_from_fork+0x22/0x30
[  260.739603] task:iou-wrk-517     state:S stack:    0 pid:  523 ppid:   439 flags:0x00004224
[  260.739607] Call Trace:
[  260.739609]  ? __schedule+0x5b7/0x6d6
[  260.739614]  ? schedule+0x63/0xd5
[  260.739617]  ? schedule_timeout+0x219/0x356
[  260.739621]  ? __next_timer_interrupt+0xf1/0xf1
[  260.739624]  ? task_thread.isra.0+0x148/0x3af
[  260.739628]  ? task_thread_unbound+0xa/0xa
[  260.739632]  ? task_thread_bound+0x7/0x7
[  260.739636]  ? ret_from_fork+0x22/0x30
[  260.739647] OOM killer enabled.
[  260.739648] Restarting tasks ... done.
[  260.740077] PM: suspend exit
Quoted 6 lines

and then a set of similar messages except with s2idle instead of deep.

Reverting 5695e51619 ("Merge tag 'io_uring-worker.v3-2021-02-25' of
git://git.kernel.dk/linux-block") appears to resolve the issue. I have not yet bisected further. Let me know which troubleshooting steps I should perform next.

Can you try and pull in:

git://git.kernel.dk/linux-block io_uring-5.12

Quoted 7 lines
Quoted 5 lines

and see if that resolves it? I usually always run -git on my laptop as well, but something broke it in the merge window so I need to figure out what that is first...

What distro are you running?

You probably want this on top...

And if you've verified that that one works OK, can you try this variant instead?

fs/io-wq.c +3 -0
index 1fdb2b621b51..fe004cf93c4b 100644
@@ -16,6 +16,7 @@
 #include <linux/rculist_nulls.h>
 #include <linux/cpu.h>
 #include <linux/tracehook.h>
+#include <linux/freezer.h>
 
 #include "../kernel/sched/sched.h"
 #include "io-wq.h"

@@ -480,6 +481,7 @@ static int io_wqe_worker(void *data)
 	io_worker_start(worker);
 
 	while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
+		try_to_freeze();
 		set_current_state(TASK_INTERRUPTIBLE);
 loop:
 		raw_spin_lock_irq(&wqe->lock);

@@ -731,6 +733,7 @@ static int io_wq_manager(void *data)
 		set_current_state(TASK_INTERRUPTIBLE);
 		io_wq_check_workers(wq);
 		schedule_timeout(HZ);
+		try_to_freeze();
 		if (fatal_signal_pending(current))
 			set_bit(IO_WQ_BIT_EXIT, &wq->state);
 	} while (!test_bit(IO_WQ_BIT_EXIT, &wq->state));
fs/io_uring.c +2 -3
index 2757675ab417..03c42f1f9862 100644
@@ -74,13 +74,11 @@
 #include <linux/fsnotify.h>
 #include <linux/fadvise.h>
 #include <linux/eventpoll.h>
-#include <linux/fs_struct.h>
 #include <linux/splice.h>
 #include <linux/task_work.h>
 #include <linux/pagemap.h>
 #include <linux/io_uring.h>
-#include <linux/blk-cgroup.h>
-#include <linux/audit.h>
+#include <linux/freezer.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/io_uring.h>

@@ -6744,6 +6748,7 @@ static int io_sq_thread(void *data)
 				io_ring_set_wakeup_flag(ctx);
 
 			schedule();
+			try_to_freeze();
 			list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
 				io_ring_clear_wakeup_flag(ctx);
 		}
Signature · 1 line
Jens Axboe
author
#5 lore raw

I tried 29be7fc03d ("io_uring: ensure that threads freeze on suspend") and it seems to work OK. The system suspends fine and no errors are printed to the kernel log.

I am using Gentoo on the machine in question.

I didn't test the other patches you supplied. Let me know if there's anything you would like me to test.

Thanks,
Alex.

maintainer
#6 lore raw
Quoted 8 lines · On 3/2/21 3:13 PM, Alex Xu (Hello71) wrote:

I tried 29be7fc03d ("io_uring: ensure that threads freeze on suspend") and it seems to work OK. The system suspends fine and no errors are printed to the kernel log.

I am using Gentoo on the machine in question.

I didn't test the other patches you supplied. Let me know if there's anything you would like me to test.

OK great, thanks. I'll add your reported/tested-by to the patch.

Signature · 1 line
Jens Axboe