locking/lockdep: Avoid triggering hardlockup from debug_show_all_locks()
authorTejun Heo <tj@kernel.org>
Mon, 22 Jan 2018 22:00:55 +0000 (14:00 -0800)
committerIngo Molnar <mingo@kernel.org>
Wed, 24 Jan 2018 09:00:09 +0000 (10:00 +0100)
commit88f1c87de11a86d839f4ce5313e552d96709b990
tree4869d6b64b9317c2eaf4df912b3dd6deec207fa4
parenta97cb0e7b3f4c6297fd857055ae8e895f402f501
locking/lockdep: Avoid triggering hardlockup from debug_show_all_locks()

debug_show_all_locks() iterates all tasks and print held locks whole
holding tasklist_lock.  This can take a while on a slow console device
and may end up triggering NMI hardlockup detector if someone else ends
up waiting for tasklist_lock.

Touch the NMI watchdog while printing the held locks to avoid
spuriously triggering the hardlockup detector.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-team@fb.com
Link: http://lkml.kernel.org/r/20180122220055.GB1771050@devbig577.frc2.facebook.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kernel/locking/lockdep.c