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authorTejun Heo <[email protected]>2018-01-22 14:00:55 -0800
committerIngo Molnar <[email protected]>2018-01-24 10:00:09 +0100
commit88f1c87de11a86d839f4ce5313e552d96709b990 (patch)
tree4869d6b64b9317c2eaf4df912b3dd6deec207fa4
parenta97cb0e7b3f4c6297fd857055ae8e895f402f501 (diff)
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 <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
-rw-r--r--kernel/locking/lockdep.c2
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");