From: Sasha Levin Date: Thu, 15 Mar 2012 21:47:20 +0000 (-0400) Subject: hung task debugging: Inject NMI when hung and going to panic X-Git-Tag: firefly_0821_release~3680^2~2843^2~4 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=625056b65ee9a8b4caf42136e0c844c15e6ec54f;p=firefly-linux-kernel-4.4.55.git 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 --- diff --git a/kernel/hung_task.c b/kernel/hung_task.c index c21449f85a2a..6df614912b9d 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"); + } } /*