From 88f1c87de11a86d839f4ce5313e552d96709b990 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 22 Jan 2018 14:00:55 -0800 Subject: [PATCH] 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 Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: kernel-team@fb.com Link: http://lkml.kernel.org/r/20180122220055.GB1771050@devbig577.frc2.facebook.com Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 5fa1324a4f29..521659044719 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -49,6 +49,7 @@ #include #include #include +#include #include @@ -4490,6 +4491,7 @@ retry: if (!unlock) if (read_trylock(&tasklist_lock)) unlock = 1; + touch_nmi_watchdog(); } while_each_thread(g, p); pr_warn("\n");