diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2007-06-08 10:29:28 +0000 |
---|---|---|
committer | Willy Tarreau <w@1wt.eu> | 2007-08-15 10:02:25 +0200 |
commit | b3b66101b6dda551a35f98c048951ba9842250fa (patch) | |
tree | dfef0f9b60cdfe4612da93cf3f7fffc4515edd82 /kernel | |
parent | 61540c3cf703e55fddb9ed6b9bf032b5c4d61813 (diff) |
[PATCH] 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 woken up path.
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'kernel')
-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 4ab17da46fd8..9b08847b8f7f 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -659,9 +659,16 @@ 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; } |