3.18.117-rt105-rc1

Hello RT Folks!

This is the RT stable review cycle of patch 3.18.117-rt105-rc1.

In addition to the applicable stable-rt patches not yet in the 3.18-rt kernel, this set includes some patches needed to fix cross-compilation build failures.

Please scream at me if I messed something up. Please test the patches too.

The -rc release will be uploaded to kernel.org and will be deleted when the final release is out. This is just a review release (or release candidate).

The pre-releases will not be pushed to the git repository, only the final release is.

If all goes well, this patch will be converted to the next main release on 8/9/2018.

To build 3.18.117-rt105-rc1 directly, the following patches should be applied:

http://www.kernel.org/pub/linux/kernel/v3.x/linux-3.18.tar.xz

http://www.kernel.org/pub/linux/kernel/v3.x/patch-3.18.117.xz

http://www.kernel.org/pub/linux/kernel/projects/rt/3.18/patch-3.18.117-rt105-rc1.patch.xz

You can also build from 3.18.117-rt104 by applying the incremental patch:

http://www.kernel.org/pub/linux/kernel/projects/rt/3.18/incr/patch-3.18.117-rt104-rt105-rc1.patch.xz

Enjoy!

Tom

Anton Blanchard (1):
powerpc/vdso64: Use double word compare on pointers

Julia Cartwright (2):
seqlock: provide the same ordering semantics as mainline
squashfs: make use of local lock in multi_cpu decompressor

Krzysztof Mazur (1):
um: Use POSIX ucontext_t instead of struct ucontext

Paul Gortmaker (1):
powerpc: ps3/device-init.c - adapt to completions using swait vs wait

Peter Zijlstra (1):
sched: Remove TASK_ALL

Philipp Schrader (1):
tracing: Fix rcu splat from idle CPU on boot

Sebastian Andrzej Siewior (5):
arm*: disable NEON in kernel mode
posix-timers: move the rcu head out of the union
alarmtimer: Prevent live lock in alarm_cancel()
locking: add types.h
net: use task_struct instead of CPU number as the queue owner on -RT

Tom Zanussi (3):
Revert "fs, jbd: pull your plug when waiting for space" s390/mm: Fix missed tsk->pagefault_disabled conversion to
pagefault_disable()
Linux 3.18.117-rt105-rc1

 arch/arm/Kconfig                          |  2 +-
 arch/arm64/crypto/Kconfig                 | 14 ++++----
 arch/powerpc/kernel/vdso64/datapage.S     |  2 +-
 arch/powerpc/kernel/vdso64/gettimeofday.S |  2 +-
 arch/powerpc/platforms/ps3/device-init.c  |  2 +-
 arch/s390/mm/fault.c                      |  2 +-
 arch/um/os-Linux/signal.c                 |  2 +-
 arch/x86/um/stub_segv.c                   |  2 +-
 fs/jbd/checkpoint.c                       |  2 --
 fs/squashfs/decompressor_multi_percpu.c   | 16 ++++++---
 include/linux/netdevice.h                 | 54 +++++++++++++++++++++++++++----
 include/linux/posix-timers.h              |  2 +-
 include/linux/sched.h                     |  1 -
 include/linux/seqlock.h                   |  1 +
 include/linux/spinlock_types_raw.h        |  2 ++
 kernel/time/alarmtimer.c                  |  2 +-
 kernel/time/posix-timers.c                |  4 +--
 kernel/trace/trace_irqsoff.c              |  4 +--
 localversion-rt                           |  2 +-
 net/core/dev.c                            |  6 +++-
 20 files changed, 89 insertions(+), 35 deletions(-)

2.14.1

From: Peter Zijlstra <[email protected]>

It's unused:

$ git grep "\<TASK_ALL\>" | wc -l
1

And dangerous, kill the bugger.

Conflicts:
include/linux/sched.h

---
 include/linux/sched.h | 1 -
 1 file changed, 1 deletion(-)

index cc7349a2c0cf..fbe198d733c2 100644
@@ -228,7 +228,6 @@ extern char ___assert_task_state[1 - 2*!!(
 
 /* Convenience macros for the sake of wake_up */
 #define TASK_NORMAL		(TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)
-#define TASK_ALL		(TASK_NORMAL | __TASK_STOPPED | __TASK_TRACED)
 
 /* get_task_state() */
 #define TASK_REPORT		(TASK_RUNNING | TASK_INTERRUPTIBLE | \

2.14.1

From: Sebastian Andrzej Siewior <[email protected]>

NEON in kernel mode is used by the crypto algorithms and raid6 code. While the raid6 code looks okay, the crypto algorithms do not: NEON is enabled on first invocation and may allocate/free/map memory before the NEON mode is disabled again.
This needs to be changed until it can be enabled.
On ARM NEON in kernel mode can be simply disabled. on ARM64 it needs to stay on due to possible EFI callbacks so here I disable each algorithm.

---
 arch/arm/Kconfig          |  2 +-
 arch/arm64/crypto/Kconfig | 14 +++++++-------
 2 files changed, 8 insertions(+), 8 deletions(-)

index d635abf51063..12b1e7a5f103 100644
@@ -2122,7 +2122,7 @@ config NEON
 
 config KERNEL_MODE_NEON
 	bool "Support for NEON in kernel mode"
-	depends on NEON && AEABI
+	depends on NEON && AEABI && !PREEMPT_RT_BASE
 	help
 	  Say Y to include support for NEON in kernel mode.
 

index 5562652c5316..003fe0718117 100644
@@ -10,42 +10,42 @@ if ARM64_CRYPTO
 
 config CRYPTO_SHA1_ARM64_CE
 	tristate "SHA-1 digest algorithm (ARMv8 Crypto Extensions)"
-	depends on ARM64 && KERNEL_MODE_NEON
+	depends on ARM64 && KERNEL_MODE_NEON && !PREEMPT_RT_BASE
 	select CRYPTO_HASH
 
 config CRYPTO_SHA2_ARM64_CE
 	tristate "SHA-224/SHA-256 digest algorithm (ARMv8 Crypto Extensions)"
-	depends on ARM64 && KERNEL_MODE_NEON
+	depends on ARM64 && KERNEL_MODE_NEON && !PREEMPT_RT_BASE
 	select CRYPTO_HASH
 
 config CRYPTO_GHASH_ARM64_CE
 	tristate "GHASH (for GCM chaining mode) using ARMv8 Crypto Extensions"
-	depends on ARM64 && KERNEL_MODE_NEON
+	depends on ARM64 && KERNEL_MODE_NEON && !PREEMPT_RT_BASE
 	select CRYPTO_HASH
 
 config CRYPTO_AES_ARM64_CE
 	tristate "AES core cipher using ARMv8 Crypto Extensions"
-	depends on ARM64 && KERNEL_MODE_NEON
+	depends on ARM64 && KERNEL_MODE_NEON && !PREEMPT_RT_BASE
 	select CRYPTO_ALGAPI
 	select CRYPTO_AES
 
 config CRYPTO_AES_ARM64_CE_CCM
 	tristate "AES in CCM mode using ARMv8 Crypto Extensions"
-	depends on ARM64 && KERNEL_MODE_NEON
+	depends on ARM64 && KERNEL_MODE_NEON && !PREEMPT_RT_BASE
 	select CRYPTO_ALGAPI
 	select CRYPTO_AES
 	select CRYPTO_AEAD
 
 config CRYPTO_AES_ARM64_CE_BLK
 	tristate "AES in ECB/CBC/CTR/XTS modes using ARMv8 Crypto Extensions"
-	depends on ARM64 && KERNEL_MODE_NEON
+	depends on ARM64 && KERNEL_MODE_NEON && !PREEMPT_RT_BASE
 	select CRYPTO_BLKCIPHER
 	select CRYPTO_AES
 	select CRYPTO_ABLK_HELPER
 
 config CRYPTO_AES_ARM64_NEON_BLK
 	tristate "AES in ECB/CBC/CTR/XTS modes using NEON instructions"
-	depends on ARM64 && KERNEL_MODE_NEON
+	depends on ARM64 && KERNEL_MODE_NEON && !PREEMPT_RT_BASE
 	select CRYPTO_BLKCIPHER
 	select CRYPTO_AES
 	select CRYPTO_ABLK_HELPER

2.14.1

From: Sebastian Andrzej Siewior <[email protected]>

On RT the timer can be preempted while running and therefore we wait with timer_wait_for_callback() for the timer to complete (instead of busy looping). The RCU-readlock is held to ensure that this posix timer is not removed while we wait on it.
If the timer is removed then it invokes call_rcu() with a pointer that is shared with the hrtimer because it is part of the same union. In order to avoid any possible side effects I am moving the rcu pointer out of the union.

---
 include/linux/posix-timers.h | 2 +-
 kernel/time/posix-timers.c   | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

index 907f3fd191ac..e2e43c61f6a1 100644
@@ -92,8 +92,8 @@ struct k_itimer {
 			struct alarm alarmtimer;
 			ktime_t interval;
 		} alarm;
-		struct rcu_head rcu;
 	} it;
+	struct rcu_head rcu;
 };
 
 struct k_clock {

index b5e0ff549422..bdf91054e6c3 100644
@@ -560,7 +560,7 @@ static struct k_itimer * alloc_posix_timer(void)
 
 static void k_itimer_rcu_free(struct rcu_head *head)
 {
-	struct k_itimer *tmr = container_of(head, struct k_itimer, it.rcu);
+	struct k_itimer *tmr = container_of(head, struct k_itimer, rcu);
 
 	kmem_cache_free(posix_timers_cache, tmr);
 }

@@ -577,7 +577,7 @@ static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
 	}
 	put_pid(tmr->it_pid);
 	sigqueue_free(tmr->sigq);
-	call_rcu(&tmr->it.rcu, k_itimer_rcu_free);
+	call_rcu(&tmr->rcu, k_itimer_rcu_free);
 }
 
 static struct k_clock *clockid_to_kclock(const clockid_t id)

2.14.1

From: Philipp Schrader <[email protected]>

With PREEMPT_RT and most of the lockdep-related options enabled I encountered this splat when booting our DRA7 evaluation module:

[    0.055073]
[    0.055076] ===============================
[    0.055079] [ INFO: suspicious RCU usage. ]
[    0.055084] 4.1.6+ #2 Not tainted
[    0.055086] -------------------------------
[    0.055090] include/trace/events/hist.h:31 suspicious
rcu_dereference_check() usage!
[    0.055093]
[    0.055093] other info that might help us debug this:
[    0.055093]
[    0.055097]
[    0.055097] RCU used illegally from idle CPU!
[    0.055097] rcu_scheduler_active = 1, debug_locks = 1
[    0.055100] RCU used illegally from extended quiescent state!
[    0.055104] no locks held by swapper/0/0.
[    0.055106]
[    0.055106] stack backtrace:
[    0.055112] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.1.6+ #2
[    0.055116] Hardware name: Generic DRA74X (Flattened Device Tree)
[    0.055130] [<c00196b8>] (unwind_backtrace) from [<c001515c>]
(show_stack+0x20/0x24)
[    0.055146] [<c001515c>] (show_stack) from [<c07bc408>]
(dump_stack+0x84/0xa0)
[    0.055160] [<c07bc408>] (dump_stack) from [<c009bc38>]
(lockdep_rcu_suspicious+0xb0/0x110)
[    0.055172] [<c009bc38>] (lockdep_rcu_suspicious) from [<c01246c4>]
(time_hardirqs_off+0x2b8/0x3c8)
[    0.055184] [<c01246c4>] (time_hardirqs_off) from [<c009a218>]
(trace_hardirqs_off_caller+0x2c/0xf4)
[    0.055194] [<c009a218>] (trace_hardirqs_off_caller) from
[<c009a2f4>] (trace_hardirqs_off+0x14/0x18)
[    0.055204] [<c009a2f4>] (trace_hardirqs_off) from [<c00c7ecc>]
(rcu_idle_enter+0x78/0xcc)
[    0.055213] [<c00c7ecc>] (rcu_idle_enter) from [<c0093eb0>]
(cpu_startup_entry+0x190/0x518)
[    0.055222] [<c0093eb0>] (cpu_startup_entry) from [<c07b95b4>]
(rest_init+0x13c/0x17c)
[    0.055231] [<c07b95b4>] (rest_init) from [<c0b32c74>]
(start_kernel+0x320/0x380)
[    0.055238] [<c0b32c74>] (start_kernel) from [<8000807c>] (0x8000807c)

As per Steve Rotstedt's suggestion I changed the trace_* calls to trace_*_rcuidle calls. He pointed out that the trace points were getting triggered when rcu wasn't watching.

---
 kernel/trace/trace_irqsoff.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index d1940b095d85..9cbc38722905 100644
@@ -452,7 +452,7 @@ EXPORT_SYMBOL_GPL(stop_critical_timings);
 #ifdef CONFIG_PROVE_LOCKING
 void time_hardirqs_on(unsigned long a0, unsigned long a1)
 {
-	trace_preemptirqsoff_hist(IRQS_ON, 0);
+	trace_preemptirqsoff_hist_rcuidle(IRQS_ON, 0);
 	if (!preempt_trace() && irq_trace())
 		stop_critical_timing(a0, a1);
 }

@@ -461,7 +461,7 @@ void time_hardirqs_off(unsigned long a0, unsigned long a1)
 {
 	if (!preempt_trace() && irq_trace())
 		start_critical_timing(a0, a1);
-	trace_preemptirqsoff_hist(IRQS_OFF, 1);
+	trace_preemptirqsoff_hist_rcuidle(IRQS_OFF, 1);
 }
 
 #else /* !CONFIG_PROVE_LOCKING */

2.14.1

From: Sebastian Andrzej Siewior <[email protected]>

If alarm_try_to_cancel() requires a retry, then depending on the priority setting the retry loop might prevent timer callback completion on RT. Prevent that by waiting for completion on RT, no change for a non RT kernel.

---
 kernel/time/alarmtimer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 119847b93ba6..5a5e05fc92a3 100644
@@ -395,7 +395,7 @@ int alarm_cancel(struct alarm *alarm)
 		int ret = alarm_try_to_cancel(alarm);
 		if (ret >= 0)
 			return ret;
-		cpu_relax();
+		hrtimer_wait_for_timer(&alarm->timer);
 	}
 }
 EXPORT_SYMBOL_GPL(alarm_cancel);

2.14.1

From: Sebastian Andrzej Siewior <[email protected]>

During the stable update the arm architecture did not compile anymore due to missing definition of u16/32.

---
 include/linux/spinlock_types_raw.h | 2 ++
 1 file changed, 2 insertions(+)

index edffc4d53fc9..03235b475b77 100644
@@ -1,6 +1,8 @@
 #ifndef __LINUX_SPINLOCK_TYPES_RAW_H
 #define __LINUX_SPINLOCK_TYPES_RAW_H
 
+#include <linux/types.h>
+
 #if defined(CONFIG_SMP)
 # include <asm/spinlock_types.h>
 #else

2.14.1

From: Sebastian Andrzej Siewior <[email protected]>

In commit ("net: move xmit_recursion to per-task variable on -RT") the recursion level was changed to be per-task since we can get preempted in BH on -RT. The lock owner should consequently be recorded as the task that holds the lock and not the CPU. Otherwise we trigger the "Dead loop on virtual device" warning on SMP systems.

Conflicts:
net/core/dev.c

---
 include/linux/netdevice.h | 54 +++++++++++++++++++++++++++++++++++++++++------
 net/core/dev.c            |  6 +++++-
 2 files changed, 53 insertions(+), 7 deletions(-)

index 2bb8ddaf641e..9cc578ba2037 100644
@@ -556,7 +556,11 @@ struct netdev_queue {
  * write mostly part
  */
 	spinlock_t		_xmit_lock ____cacheline_aligned_in_smp;
+#ifdef CONFIG_PREEMPT_RT_FULL
+	struct task_struct	*xmit_lock_owner;
+#else
 	int			xmit_lock_owner;
+#endif
 	/*
 	 * please use this field instead of dev->trans_start
 	 */

@@ -3080,41 +3084,79 @@ static inline u32 netif_msg_init(int debug_value, int default_msg_enable_bits)
 	return (1 << debug_value) - 1;
 }
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+static inline void netdev_queue_set_owner(struct netdev_queue *txq, int cpu)
+{
+	txq->xmit_lock_owner = current;
+}
+
+static inline void netdev_queue_clear_owner(struct netdev_queue *txq)
+{
+	txq->xmit_lock_owner = NULL;
+}
+
+static inline bool netdev_queue_has_owner(struct netdev_queue *txq)
+{
+	if (txq->xmit_lock_owner != NULL)
+		return true;
+	return false;
+}
+
+#else
+
+static inline void netdev_queue_set_owner(struct netdev_queue *txq, int cpu)
+{
+	txq->xmit_lock_owner = cpu;
+}
+
+static inline void netdev_queue_clear_owner(struct netdev_queue *txq)
+{
+	txq->xmit_lock_owner = -1;
+}
+
+static inline bool netdev_queue_has_owner(struct netdev_queue *txq)
+{
+	if (txq->xmit_lock_owner != -1)
+		return true;
+	return false;
+}
+#endif
+
 static inline void __netif_tx_lock(struct netdev_queue *txq, int cpu)
 {
 	spin_lock(&txq->_xmit_lock);
-	txq->xmit_lock_owner = cpu;
+	netdev_queue_set_owner(txq, cpu);
 }
 
 static inline void __netif_tx_lock_bh(struct netdev_queue *txq)
 {
 	spin_lock_bh(&txq->_xmit_lock);
-	txq->xmit_lock_owner = smp_processor_id();
+	netdev_queue_set_owner(txq, smp_processor_id());
 }
 
 static inline bool __netif_tx_trylock(struct netdev_queue *txq)
 {
 	bool ok = spin_trylock(&txq->_xmit_lock);
 	if (likely(ok))
-		txq->xmit_lock_owner = smp_processor_id();
+		netdev_queue_set_owner(txq, smp_processor_id());
 	return ok;
 }
 
 static inline void __netif_tx_unlock(struct netdev_queue *txq)
 {
-	txq->xmit_lock_owner = -1;
+	netdev_queue_clear_owner(txq);
 	spin_unlock(&txq->_xmit_lock);
 }
 
 static inline void __netif_tx_unlock_bh(struct netdev_queue *txq)
 {
-	txq->xmit_lock_owner = -1;
+	netdev_queue_clear_owner(txq);
 	spin_unlock_bh(&txq->_xmit_lock);
 }
 
 static inline void txq_trans_update(struct netdev_queue *txq)
 {
-	if (txq->xmit_lock_owner != -1)
+	if (netdev_queue_has_owner(txq))
 		txq->trans_start = jiffies;
 }
 

index eb39270ac306..bbdec43abe1c 100644
@@ -3028,7 +3028,11 @@ static int __dev_queue_xmit(struct sk_buff *skb, void *accel_priv)
 	if (dev->flags & IFF_UP) {
 		int cpu = smp_processor_id(); /* ok because BHs are off */
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+		if (txq->xmit_lock_owner != current) {
+#else
 		if (txq->xmit_lock_owner != cpu) {
+#endif
 
 			if (xmit_rec_read() > RECURSION_LIMIT)
 				goto recursion_alert;

@@ -6233,7 +6237,7 @@ static void netdev_init_one_queue(struct net_device *dev,
 	/* Initialize queue lock */
 	spin_lock_init(&queue->_xmit_lock);
 	netdev_set_xmit_lockdep_class(&queue->_xmit_lock, dev->type);
-	queue->xmit_lock_owner = -1;
+	netdev_queue_clear_owner(queue);
 	netdev_queue_numa_node_write(queue, NUMA_NO_NODE);
 	queue->dev = dev;
 #ifdef CONFIG_BQL

2.14.1

From: Julia Cartwright <[email protected]>

The mainline implementation of read_seqbegin() orders prior loads w.r.t. the read-side critical section. Fixup the RT writer-boosting implementation to provide the same guarantee.

Also, while we're here, update the usage of ACCESS_ONCE() to use READ_ONCE().

---
 include/linux/seqlock.h | 1 +
 1 file changed, 1 insertion(+)

index 4acd0e2fb5cb..efa234031230 100644
@@ -338,6 +338,7 @@ repeat:
 		spin_unlock_wait(&sl->lock);
 		goto repeat;
 	}
+	smp_rmb();
 	return ret;
 }
 #endif

2.14.1

From: Julia Cartwright <[email protected]>

Currently, the squashfs multi_cpu decompressor makes use of get_cpu_ptr()/put_cpu_ptr(), which unconditionally disable preemption during decompression.

Because the workload is distributed across CPUs, all CPUs can observe a very high wakeup latency, which has been seen to be as much as 8000us.

Convert this decompressor to make use of a local lock, which will allow execution of the decompressor with preemption-enabled, but also ensure concurrent accesses to the percpu compressor data on the local CPU will be serialized.

---
 fs/squashfs/decompressor_multi_percpu.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

index 23a9c28ad8ea..6a73c4fa88e7 100644
@@ -10,6 +10,7 @@
 #include <linux/slab.h>
 #include <linux/percpu.h>
 #include <linux/buffer_head.h>
+#include <linux/locallock.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"

@@ -25,6 +26,8 @@ struct squashfs_stream {
 	void		*stream;
 };
 
+static DEFINE_LOCAL_IRQ_LOCK(stream_lock);
+
 void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
 						void *comp_opts)
 {

@@ -79,10 +82,15 @@ int squashfs_decompress(struct squashfs_sb_info *msblk, struct buffer_head **bh,
 {
 	struct squashfs_stream __percpu *percpu =
 			(struct squashfs_stream __percpu *) msblk->stream;
-	struct squashfs_stream *stream = get_cpu_ptr(percpu);
-	int res = msblk->decompressor->decompress(msblk, stream->stream, bh, b,
-		offset, length, output);
-	put_cpu_ptr(stream);
+	struct squashfs_stream *stream;
+	int res;
+
+	stream = get_locked_ptr(stream_lock, percpu);
+
+	res = msblk->decompressor->decompress(msblk, stream->stream, bh, b,
+			offset, length, output);
+
+	put_locked_ptr(stream_lock, stream);
 
 	if (res < 0)
 		ERROR("%s decompression failed, data probably corrupt\n",

2.14.1

This reverts commit 3b5cf23e6b87a938522eb074baeb034e66dc9cb3.

Similar to commit d5bc2c7b2cc0 Revert "fs: jbd2: pull your plug when waiting for space", according to Sebastian Siewior: this "is the same thing but for ext3/jbd. The code was removed at some point so I did not revert in my tree."

shouldn't be needed since commit "locking/rt-mutex: fix deadlock in device mapper / block-IO".

---
 fs/jbd/checkpoint.c | 2 --
 1 file changed, 2 deletions(-)

index 95debd71e5fa..08c03044abdd 100644
@@ -129,8 +129,6 @@ void __log_wait_for_space(journal_t *journal)
 		if (journal->j_flags & JFS_ABORT)
 			return;
 		spin_unlock(&journal->j_state_lock);
-		if (current->plug)
-			io_schedule();
 		mutex_lock(&journal->j_checkpoint_mutex);
 
 		/*

2.14.1

The series claims to have 15 patches and I see only the first 10 (in my inbox, rt-users and linux-kernel).

Sebastian

Hi Sebastian,

Yeah, my script was broken and didn't send the last third - resent. Thanks for letting me know,

Tom

From: Anton Blanchard <[email protected]>

commit 5045ea37377ce8cca6890d32b127ad6770e6dce5 upstream.

__kernel_get_syscall_map() and __kernel_clock_getres() use cmpli to check if the passed in pointer is non zero. cmpli maps to a 32 bit compare on binutils, so we ignore the top 32 bits.

A simple test case can be created by passing in a bogus pointer with the bottom 32 bits clear. Using a clk_id that is handled by the VDSO, then one that is handled by the kernel shows the problem:

  printf("%d\n", clock_getres(CLOCK_REALTIME, (void *)0x100000000));
  printf("%d\n", clock_getres(CLOCK_BOOTTIME, (void *)0x100000000));

And we get:

0
-1

The bigger issue is if we pass a valid pointer with the bottom 32 bits clear, in this case we will return success but won't write any data to the pointer.

I stumbled across this issue because the LLVM integrated assembler doesn't accept cmpli with 3 arguments. Fix this by converting them to cmpldi.

---
 arch/powerpc/kernel/vdso64/datapage.S     | 2 +-
 arch/powerpc/kernel/vdso64/gettimeofday.S | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

index 79796de11737..3263ee23170d 100644
@@ -57,7 +57,7 @@ V_FUNCTION_BEGIN(__kernel_get_syscall_map)
 	bl	V_LOCAL_FUNC(__get_datapage)
 	mtlr	r12
 	addi	r3,r3,CFG_SYSCALL_MAP64
-	cmpli	cr0,r4,0
+	cmpldi	cr0,r4,0
 	crclr	cr0*4+so
 	beqlr
 	li	r0,__NR_syscalls

index a76b4af37ef2..382021324883 100644
@@ -145,7 +145,7 @@ V_FUNCTION_BEGIN(__kernel_clock_getres)
 	bne	cr0,99f
 
 	li	r3,0
-	cmpli	cr0,r4,0
+	cmpldi	cr0,r4,0
 	crclr	cr0*4+so
 	beqlr
 	lis	r5,CLOCK_REALTIME_RES@h

2.14.1

From: Paul Gortmaker <[email protected]>

To fix:

cc1: warnings being treated as errors
arch/powerpc/platforms/ps3/device-init.c: In function 'ps3_notification_read_write':
arch/powerpc/platforms/ps3/device-init.c:755:2: error: passing argument 1 of 'prepare_to_wait_event' from incompatible pointer type arch/powerpc/platforms/ps3/device-init.c:755:2: error: passing argument 1 of 'abort_exclusive_wait' from incompatible pointer type arch/powerpc/platforms/ps3/device-init.c:755:2: error: passing argument 1 of 'finish_wait' from incompatible pointer type arch/powerpc/platforms/ps3/device-init.o] Error 1
make[3]: *** Waiting for unfinished jobs....

---
 arch/powerpc/platforms/ps3/device-init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 3f175e8aedb4..c4c02f91904c 100644
@@ -752,7 +752,7 @@ static int ps3_notification_read_write(struct ps3_notification_device *dev,
 	}
 	pr_debug("%s:%u: notification %s issued\n", __func__, __LINE__, op);
 
-	res = wait_event_interruptible(dev->done.wait,
+	res = swait_event_interruptible(dev->done.wait,
 				       dev->done.done || kthread_should_stop());
 	if (kthread_should_stop())
 		res = -EINTR;

2.14.1

commit 7be67fb433a0 ("mm: pagefault_disabled()") does this for s390:

  -       if (unlikely(!user_space_fault(regs) || in_atomic() || !mm ||
  +       if (unlikely(!user_space_fault(regs) || !mm ||
                       tsk->pagefault_disabled))

whereas elsewhere it does the right thing e.g other arches:

- if (in_atomic() || !mm || current->pagefault_disabled)
+ if (!mm || pagefault_disabled())

i.e. because of the linebreak it misses the tsk->pagefault_disabled and leaves it unconverted.

So fix that up and use pagefault_disabled() as intended.

---
 arch/s390/mm/fault.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 43ec237a17e2..466154e1dfc0 100644
@@ -436,7 +436,7 @@ static inline int do_exception(struct pt_regs *regs, int access)
 	 */
 	fault = VM_FAULT_BADCONTEXT;
 	if (unlikely(!user_space_fault(regs) || !mm ||
-		     tsk->pagefault_disabled))
+		     pagefault_disabled()))
 		goto out;
 
 	address = trans_exc_code & __FAIL_ADDR_MASK;

2.14.1

From: Krzysztof Mazur <[email protected]>

glibc 2.26 removed the 'struct ucontext' to "improve" POSIX compliance and break programs, including User Mode Linux. Fix User Mode Linux by using POSIX ucontext_t.

This fixes:

arch/um/os-Linux/signal.c: In function 'hard_handler':
arch/um/os-Linux/signal.c:163:22: error: dereferencing pointer to incomplete type 'struct ucontext'
mcontext_t *mc = &uc->uc_mcontext;
arch/x86/um/stub_segv.c: In function 'stub_segv_handler':
arch/x86/um/stub_segv.c:16:13: error: dereferencing pointer to incomplete type 'struct ucontext'

          &uc->uc_mcontext);

---
 arch/um/os-Linux/signal.c | 2 +-
 arch/x86/um/stub_segv.c   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

index 7b605e4dfffa..2ac6a7e5a179 100644
@@ -135,7 +135,7 @@ static void (*handlers[_NSIG])(int sig, struct siginfo *si, mcontext_t *mc) = {
 
 static void hard_handler(int sig, siginfo_t *si, void *p)
 {
-	struct ucontext *uc = p;
+	ucontext_t *uc = p;
 	mcontext_t *mc = &uc->uc_mcontext;
 	unsigned long pending = 1UL << sig;
 

index 1518d2805ae8..fd6825537b97 100644
@@ -10,7 +10,7 @@
 void __attribute__ ((__section__ (".__syscall_stub")))
 stub_segv_handler(int sig, siginfo_t *info, void *p)
 {
-	struct ucontext *uc = p;
+	ucontext_t *uc = p;
 
 	GET_FAULTINFO_FROM_MC(*((struct faultinfo *) STUB_DATA),
 			      &uc->uc_mcontext);

2.14.1

---
 localversion-rt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index d068aedeebe2..39f988470301 100644
@@ -1 +1 @@
--rt104
+-rt105-rc1

2.14.1