diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2007-06-08 20:46:57 (GMT) |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-06-09 00:23:34 (GMT) |
commit | c0d1d2bf5a28f78def7b68ca1eb5ba31aafd43a1 (patch) | |
tree | c51260793d12005dcc244a1304193ce9898ed9cc | |
parent | 51b94d2a5a90d4800e74d7348bcde098a28f4fb3 (diff) | |
download | linux-fsl-qoriq-c0d1d2bf5a28f78def7b68ca1eb5ba31aafd43a1.tar.xz |
rt-mutex: fix stale return value
Alexey Kuznetsov found some problems in the pi-futex code.
The major problem is a stale return value in rt_mutex_slowlock():
When the pi chain walk returns -EDEADLK, but the waiter was woken up during
the phases where the locks were dropped, the rtmutex could be acquired, but
due to the stale return value -EDEADLK returned to the caller.
Reset the return value in the retry path.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | kernel/rtmutex.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index 12879f6..a273183 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -636,9 +636,16 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state, * all over without going into schedule to try * to get the lock now: */ - if (unlikely(!waiter.task)) + if (unlikely(!waiter.task)) { + /* + * Reset the return value. We might + * have returned with -EDEADLK and the + * owner released the lock while we + * were walking the pi chain. + */ + ret = 0; continue; - + } if (unlikely(ret)) break; } |