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watchdog: Mark watchdog touch functions as notrace

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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 ce4f06dcbb ("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: ce4f06dcbb ("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
This commit is contained in:
Vincent Whitchurch 2018-08-21 17:25:07 +02:00 committed by Thomas Gleixner
parent 5b394b2ddf
commit cb9d7fd51d
3 changed files with 4 additions and 4 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

4
kernel/watchdog.c
View file

@ -261,7 +261,7 @@ 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
@ -270,7 +270,7 @@ void touch_softlockup_watchdog_sched(void)
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());

2
kernel/watchdog_hld.c
View file

@ -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

2
kernel/workqueue.c
View file

@ -5574,7 +5574,7 @@ static void wq_watchdog_timer_fn(struct timer_list *unused)
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;