diff options
| author | Bjørn Mork <bjorn@mork.no> | 2012-12-19 20:51:31 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-01-17 08:45:56 -0800 |
| commit | b791ca8fdc546678386a98a17be6f872472f50a4 (patch) | |
| tree | 511cbca9708cf71a53389b6ddce67e0074cb54f4 /kernel | |
| parent | 19130bd42d6cd68525ee2cd77c386d5a954800c1 (diff) | |
watchdog: Fix disable/enable regression
commit 3935e89505a1c3ab3f3b0c7ef0eae54124f48905 upstream.
Commit 8d4516904b39 ("watchdog: Fix CPU hotplug regression") causes an
oops or hard lockup when doing
echo 0 > /proc/sys/kernel/nmi_watchdog
echo 1 > /proc/sys/kernel/nmi_watchdog
and the kernel is booted with nmi_watchdog=1 (default)
Running laptop-mode-tools and disconnecting/connecting AC power will
cause this to trigger, making it a common failure scenario on laptops.
Instead of bailing out of watchdog_disable() when !watchdog_enabled we
can initialize the hrtimer regardless of watchdog_enabled status. This
makes it safe to call watchdog_disable() in the nmi_watchdog=0 case,
without the negative effect on the enabled => disabled => enabled case.
All these tests pass with this patch:
- nmi_watchdog=1
echo 0 > /proc/sys/kernel/nmi_watchdog
echo 1 > /proc/sys/kernel/nmi_watchdog
- nmi_watchdog=0
echo 0 > /sys/devices/system/cpu/cpu1/online
- nmi_watchdog=0
echo mem > /sys/power/state
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=51661
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Cc: Norbert Warmuth <nwarmuth@t-online.de>
Cc: Joseph Salisbury <joseph.salisbury@canonical.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/watchdog.c | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/kernel/watchdog.c b/kernel/watchdog.c index c8c21be11ab..762081c1dcb 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -343,6 +343,10 @@ static void watchdog_enable(unsigned int cpu) { struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer); + /* kick off the timer for the hardlockup detector */ + hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + hrtimer->function = watchdog_timer_fn; + if (!watchdog_enabled) { kthread_park(current); return; @@ -351,10 +355,6 @@ static void watchdog_enable(unsigned int cpu) /* Enable the perf event */ watchdog_nmi_enable(cpu); - /* kick off the timer for the hardlockup detector */ - hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); - hrtimer->function = watchdog_timer_fn; - /* done here because hrtimer_start can only pin to smp_processor_id() */ hrtimer_start(hrtimer, ns_to_ktime(get_sample_period()), HRTIMER_MODE_REL_PINNED); @@ -368,9 +368,6 @@ static void watchdog_disable(unsigned int cpu) { struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer); - if (!watchdog_enabled) - return; - watchdog_set_prio(SCHED_NORMAL, 0); hrtimer_cancel(hrtimer); /* disable the perf event */ |