diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2011-06-06 12:32:43 +0200 |
|---|---|---|
| committer | Andi Kleen <ak@linux.intel.com> | 2011-08-01 13:54:55 -0700 |
| commit | d30a7fe49d445fcaf58e1fac46de3f931f37a81d (patch) | |
| tree | 4dfc17a5309215a8a9b7a19605b37d031a7bb3ba /kernel | |
| parent | 0fc485b9d3424421d751d9631ea850a8a6c4cae0 (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>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
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 54286798c37b..e6c932b4ddc6 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -3250,7 +3250,7 @@ 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); |