| From cb9d7fd51d9fbb329d182423bd7b92d0f8cb0e01 Mon Sep 17 00:00:00 2001 |
| From: Vincent Whitchurch <vincent.whitchurch@axis.com> |
| Date: Tue, 21 Aug 2018 17:25:07 +0200 |
| Subject: watchdog: Mark watchdog touch functions as notrace |
| |
| From: Vincent Whitchurch <vincent.whitchurch@axis.com> |
| |
| commit cb9d7fd51d9fbb329d182423bd7b92d0f8cb0e01 upstream. |
| |
| Some architectures need to use stop_machine() to patch functions for |
| ftrace, and the assumption is that the stopped CPUs do not make function |
| calls to traceable functions when they are in the stopped state. |
| |
| Commit ce4f06dcbb5d ("stop_machine: Touch_nmi_watchdog() after |
| MULTI_STOP_PREPARE") added calls to the watchdog touch functions from |
| the stopped CPUs and those functions lack notrace annotations. This |
| leads to crashes when enabling/disabling ftrace on ARM kernels built |
| with the Thumb-2 instruction set. |
| |
| Fix it by adding the necessary notrace annotations. |
| |
| Fixes: ce4f06dcbb5d ("stop_machine: Touch_nmi_watchdog() after MULTI_STOP_PREPARE") |
| Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| Cc: Peter Zijlstra <peterz@infradead.org> |
| Cc: oleg@redhat.com |
| Cc: tj@kernel.org |
| Cc: stable@vger.kernel.org |
| Link: https://lkml.kernel.org/r/20180821152507.18313-1-vincent.whitchurch@axis.com |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| kernel/watchdog.c | 4 ++-- |
| kernel/watchdog_hld.c | 2 +- |
| kernel/workqueue.c | 2 +- |
| 3 files changed, 4 insertions(+), 4 deletions(-) |
| |
| --- a/kernel/watchdog.c |
| +++ b/kernel/watchdog.c |
| @@ -265,7 +265,7 @@ static void __touch_watchdog(void) |
| * entering idle state. This should only be used for scheduler events. |
| * Use touch_softlockup_watchdog() for everything else. |
| */ |
| -void touch_softlockup_watchdog_sched(void) |
| +notrace void touch_softlockup_watchdog_sched(void) |
| { |
| /* |
| * Preemption can be enabled. It doesn't matter which CPU's timestamp |
| @@ -274,7 +274,7 @@ void touch_softlockup_watchdog_sched(voi |
| raw_cpu_write(watchdog_touch_ts, 0); |
| } |
| |
| -void touch_softlockup_watchdog(void) |
| +notrace void touch_softlockup_watchdog(void) |
| { |
| touch_softlockup_watchdog_sched(); |
| wq_watchdog_touch(raw_smp_processor_id()); |
| --- a/kernel/watchdog_hld.c |
| +++ b/kernel/watchdog_hld.c |
| @@ -29,7 +29,7 @@ static struct cpumask dead_events_mask; |
| static unsigned long hardlockup_allcpu_dumped; |
| static atomic_t watchdog_cpus = ATOMIC_INIT(0); |
| |
| -void arch_touch_nmi_watchdog(void) |
| +notrace void arch_touch_nmi_watchdog(void) |
| { |
| /* |
| * Using __raw here because some code paths have |
| --- a/kernel/workqueue.c |
| +++ b/kernel/workqueue.c |
| @@ -5484,7 +5484,7 @@ static void wq_watchdog_timer_fn(unsigne |
| mod_timer(&wq_watchdog_timer, jiffies + thresh); |
| } |
| |
| -void wq_watchdog_touch(int cpu) |
| +notrace void wq_watchdog_touch(int cpu) |
| { |
| if (cpu >= 0) |
| per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies; |