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author | Bjørn Mork <bjorn@mork.no> | 2012-12-19 20:51:31 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-19 12:10:33 -0800 |
commit | 3935e89505a1c3ab3f3b0c7ef0eae54124f48905 (patch) | |
tree | 8cfa921612d9596b2baf98f23f7e797092bcaf11 /arch/arm/mach-nomadik | |
parent | 74779e22261172ea728b989310f6ecc991b57d62 (diff) | |
download | op-kernel-dev-3935e89505a1c3ab3f3b0c7ef0eae54124f48905.zip op-kernel-dev-3935e89505a1c3ab3f3b0c7ef0eae54124f48905.tar.gz |
watchdog: Fix disable/enable regression
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
Cc: <stable@vger.kernel.org> # v3.7
Cc: Norbert Warmuth <nwarmuth@t-online.de>
Cc: Joseph Salisbury <joseph.salisbury@canonical.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/arm/mach-nomadik')
0 files changed, 0 insertions, 0 deletions