[PATCH] detect soft lockups

This patch adds a new kernel debug feature: CONFIG_DETECT_SOFTLOCKUP.

When enabled then per-CPU watchdog threads are started, which try to run
once per second.  If they get delayed for more than 10 seconds then a
callback from the timer interrupt detects this condition and prints out a
warning message and a stack dump (once per lockup incident).  The feature
is otherwise non-intrusive, it doesnt try to unlock the box in any way, it
only gets the debug info out, automatically, and on all CPUs affected by
the lockup.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-Off-By: Matthias Urlichs <smurf@smurf.noris.de>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index eaacd5cb5889..d967e875ee82 100644
--- a/kernel/power/swsusp.c
+++ b/kernel/power/swsusp.c
@@ -1059,6 +1059,7 @@ int swsusp_resume(void)
         BUG_ON(!error);
         restore_processor_state();
         restore_highmem();
+        touch_softlockup_watchdog();
         device_power_up();
         local_irq_enable();
         return error;