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authorThomas Gleixner <tglx@linutronix.de>2007-06-08 16:46:58 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-06-08 20:23:34 -0400
commit1a539a87280b3032fd12bc93a4a82f1d8aa97ca8 (patch)
tree6dea1610ba5ff54f0e3f845d83bfc68ffc162e31 /kernel/rtmutex.c
parentc0d1d2bf5a28f78def7b68ca1eb5ba31aafd43a1 (diff)
rt-mutex: fix chain walk early wakeup bug
Alexey Kuznetsov found some problems in the pi-futex code. One of the root causes is: When a wakeup happens, we do not to stop the chain walk so we follow a not longer relevant locking chain. Drop out when this happens. 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>
Diffstat (limited to 'kernel/rtmutex.c')
-rw-r--r--kernel/rtmutex.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index a273183c37a0..a6fbb4130521 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -189,6 +189,19 @@ int rt_mutex_adjust_prio_chain(struct task_struct *task,
189 if (!waiter || !waiter->task) 189 if (!waiter || !waiter->task)
190 goto out_unlock_pi; 190 goto out_unlock_pi;
191 191
192 /*
193 * Check the orig_waiter state. After we dropped the locks,
194 * the previous owner of the lock might have released the lock
195 * and made us the pending owner:
196 */
197 if (orig_waiter && !orig_waiter->task)
198 goto out_unlock_pi;
199
200 /*
201 * Drop out, when the task has no waiters. Note,
202 * top_waiter can be NULL, when we are in the deboosting
203 * mode!
204 */
192 if (top_waiter && (!task_has_pi_waiters(task) || 205 if (top_waiter && (!task_has_pi_waiters(task) ||
193 top_waiter != task_top_pi_waiter(task))) 206 top_waiter != task_top_pi_waiter(task)))
194 goto out_unlock_pi; 207 goto out_unlock_pi;