linux/kernel/power
Sameer Nanda 45226e944c NMI watchdog: fix for lockup detector breakage on resume
On the suspend/resume path the boot CPU does not go though an
offline->online transition.  This breaks the NMI detector post-resume
since it depends on PMU state that is lost when the system gets
suspended.

Fix this by forcing a CPU offline->online transition for the lockup
detector on the boot CPU during resume.

To provide more context, we enable NMI watchdog on Chrome OS.  We have
seen several reports of systems freezing up completely which indicated
that the NMI watchdog was not firing for some reason.

Debugging further, we found a simple way of repro'ing system freezes --
issuing the command 'tasket 1 sh -c "echo nmilockup > /proc/breakme"'
after the system has been suspended/resumed one or more times.

With this patch in place, the system freeze result in panics, as
expected.

These panics provide a nice stack trace for us to debug the actual issue
causing the freeze.

[akpm@linux-foundation.org: fiddle with code comment]
[akpm@linux-foundation.org: make lockup_detector_bootcpu_resume() conditional on CONFIG_SUSPEND]
[akpm@linux-foundation.org: fix section errors]
Signed-off-by: Sameer Nanda <snanda@chromium.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30 17:25:13 -07:00
..
Kconfig PM / Sleep: Separate printing suspend times from initcall_debug 2012-07-01 13:31:23 +02:00
Makefile PM / Sleep: Add user space interface for manipulating wakeup sources, v3 2012-05-01 21:26:05 +02:00
autosleep.c PM / Sleep: Add "prevent autosleep time" statistics to wakeup sources 2012-05-01 21:25:49 +02:00
block_io.c block: kill off REQ_UNPLUG 2011-03-10 08:52:27 +01:00
console.c PM / VT: Cleanup #if defined uglyness and fix compile error 2011-10-16 23:28:51 +02:00
hibernate.c Power management updates for 3.6 2012-07-22 13:36:52 -07:00
main.c PM / Sleep: Separate printing suspend times from initcall_debug 2012-07-01 13:31:23 +02:00
power.h PM / Hibernate: Enable suspend to both for in-kernel hibernation. 2012-07-01 13:31:22 +02:00
poweroff.c Input: sysrq - drop tty argument from sysrq ops handlers 2010-08-19 22:07:06 -07:00
process.c PM / Sleep: Mitigate race between the freezer and request_firmware() 2012-03-28 23:30:28 +02:00
qos.c PM / QoS: add pm_qos_update_request_timeout() API 2012-03-28 23:31:24 +02:00
snapshot.c Power management updates for 3.4 2012-03-21 10:15:51 -07:00
suspend.c NMI watchdog: fix for lockup detector breakage on resume 2012-07-30 17:25:13 -07:00
suspend_test.c PM: Make warning in suspend_test_finish() less likely to happen 2009-10-22 08:23:45 +09:00
swap.c PM / Hibernate: Print hibernation/thaw progress indicator one line at a time. 2012-07-01 13:31:23 +02:00
user.c Make wait_for_device_probe() also do scsi_complete_async_scans() 2012-07-18 18:15:46 -07:00
wakelock.c PM / Sleep: Require CAP_BLOCK_SUSPEND to use wake_lock/wake_unlock 2012-07-19 00:00:58 +02:00