From 625056b65ee9a8b4caf42136e0c844c15e6ec54f Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Thu, 15 Mar 2012 17:47:20 -0400 Subject: hung task debugging: Inject NMI when hung and going to panic Send an NMI to all CPUs when a hung task is detected and the hung task code is configured to panic. This gives us a fairly uptodate snapshot of all CPUs in the system. This lets us get stack trace of all CPUs which makes life easier trying to debug a deadlock, and the NMI doesn't change anything since the next step is a kernel panic. Signed-off-by: Sasha Levin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/1331848040-1676-1-git-send-email-levinsasha928@gmail.com [ extended the changelog a bit ] Signed-off-by: Ingo Molnar --- kernel/hung_task.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel/hung_task.c') diff --git a/kernel/hung_task.c b/kernel/hung_task.c index c21449f85a2..6df614912b9 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -108,8 +108,10 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) touch_nmi_watchdog(); - if (sysctl_hung_task_panic) + if (sysctl_hung_task_panic) { + trigger_all_cpu_backtrace(); panic("hung_task: blocked tasks"); + } } /* -- cgit v1.2.3