diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2011-06-06 12:32:43 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-06-23 15:24:06 -0700 |
| commit | eef1d4dd92bcdb285b3ce056d8180e2867b9497c (patch) | |
| tree | 83eb79d04f405a6164eac8700e8550c48faa3c4d /kernel | |
| parent | 946ea1c993016a55eacdf6a5bc4119889cbae41d (diff) | |
lockdep: Fix lock_is_held() on recursion
commit f2513cde93f0957d5dc6c09bc24b0cccd27d8e1d upstream.
The main lock_is_held() user is lockdep_assert_held(), avoid false
assertions in lockdep_off() sections by unconditionally reporting the
lock is taken.
[ the reason this is important is a lockdep_assert_held() in ttwu()
which triggers a warning under lockdep_off() as in printk() which
can trigger another wakeup and lock up due to spinlock
recursion, as reported and heroically debugged by Arne Jansen ]
Reported-and-tested-by: Arne Jansen <lists@die-jansens.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1307398759.2497.966.camel@laptop
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/lockdep.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 9af56723c096..d86fe8966265 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -3243,7 +3243,7 @@ int lock_is_held(struct lockdep_map *lock) int ret = 0; if (unlikely(current->lockdep_recursion)) - return ret; + return 1; /* avoid false negative lockdep_assert_held() */ raw_local_irq_save(flags); check_flags(flags); |