watchdog: Mark watchdog touch functions as notrace

vwax · KAGA-KOKO · commit cb9d7fd51d9f · 2018-08-30T12:56:40.000+02:00
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 ce4f06d ("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: ce4f06d ("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
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
@@ -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());
diff --git 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
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
@@ -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;

Original file line number	Diff line number	Diff line change
`@@ -261,7 +261,7 @@ static void __touch_watchdog(void)`
`261`	`261`	`* entering idle state. This should only be used for scheduler events.`
`262`	`262`	`* Use touch_softlockup_watchdog() for everything else.`
`263`	`263`	`*/`
`264`		`-void touch_softlockup_watchdog_sched(void)`
	`264`	`+notrace void touch_softlockup_watchdog_sched(void)`
`265`	`265`	`{`
`266`	`266`	`/*`
`267`	`267`	`* Preemption can be enabled. It doesn't matter which CPU's timestamp`
`@@ -270,7 +270,7 @@ void touch_softlockup_watchdog_sched(void)`
`270`	`270`	`raw_cpu_write(watchdog_touch_ts, 0);`
`271`	`271`	`}`
`272`	`272`
`273`		`-void touch_softlockup_watchdog(void)`
	`273`	`+notrace void touch_softlockup_watchdog(void)`
`274`	`274`	`{`
`275`	`275`	`touch_softlockup_watchdog_sched();`
`276`	`276`	`wq_watchdog_touch(raw_smp_processor_id());`
Original file line number	Diff line number	Diff line change
`@@ -29,7 +29,7 @@ static struct cpumask dead_events_mask;`
`29`	`29`	`static unsigned long hardlockup_allcpu_dumped;`
`30`	`30`	`static atomic_t watchdog_cpus = ATOMIC_INIT(0);`
`31`	`31`
`32`		`-void arch_touch_nmi_watchdog(void)`
	`32`	`+notrace void arch_touch_nmi_watchdog(void)`
`33`	`33`	`{`
`34`	`34`	`/*`
`35`	`35`	`* Using __raw here because some code paths have`
Original file line number	Diff line number	Diff line change
`@@ -5574,7 +5574,7 @@ static void wq_watchdog_timer_fn(struct timer_list *unused)`
`5574`	`5574`	`mod_timer(&wq_watchdog_timer, jiffies + thresh);`
`5575`	`5575`	`}`
`5576`	`5576`
`5577`		`-void wq_watchdog_touch(int cpu)`
	`5577`	`+notrace void wq_watchdog_touch(int cpu)`
`5578`	`5578`	`{`
`5579`	`5579`	`if (cpu >= 0)`
`5580`	`5580`	`per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies;`