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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2011-06-06 12:32:43 +0200
committerIngo Molnar <mingo@elte.hu>2011-06-07 12:25:50 +0200
commitf2513cde93f0957d5dc6c09bc24b0cccd27d8e1d (patch)
treeb461cb0836170eb555b20818802c121c79e76d33 /kernel/lockdep.c
parentf339b9dc1f03591761d5d930800db24bc0eda1e1 (diff)
downloadop-kernel-dev-f2513cde93f0957d5dc6c09bc24b0cccd27d8e1d.zip
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lockdep: Fix lock_is_held() on recursion
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> Cc: <stable@kernel.org> Link: http://lkml.kernel.org/r/1307398759.2497.966.camel@laptop Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/lockdep.c')
-rw-r--r--kernel/lockdep.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 63437d0..298c927 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -3426,7 +3426,7 @@ 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);
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