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| author | Tejun Heo <tj@kernel.org> | 2018-01-22 14:00:55 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-01-24 10:00:09 +0100 |
| commit | 88f1c87de11a86d839f4ce5313e552d96709b990 (patch) | |
| tree | 4869d6b64b9317c2eaf4df912b3dd6deec207fa4 | |
| parent | a97cb0e7b3f4c6297fd857055ae8e895f402f501 (diff) | |
| download | lwn-88f1c87de11a86d839f4ce5313e552d96709b990.tar.gz lwn-88f1c87de11a86d839f4ce5313e552d96709b990.zip | |
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>
| -rw-r--r-- | kernel/locking/lockdep.c | 2 |
1 files changed, 2 insertions, 0 deletions
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 <linux/gfp.h> #include <linux/random.h> #include <linux/jhash.h> +#include <linux/nmi.h> #include <asm/sections.h> @@ -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"); |