-stable review patch. If anyone has any objections, please let us know.
------------------
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
we follow a non existing locking chain.
Drop out when this happens.
Cc: Alexey Kuznetsov <[EMAIL PROTECTED]>
Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]>
Acked-by: Ingo Molnar <[EMAIL PROTECTED]>
Signed-off-by: Chris Wright <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
---
kernel/rtmutex.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
--- linux-2.6.21.6.orig/kernel/rtmutex.c
+++ linux-2.6.21.6/kernel/rtmutex.c
@@ -212,6 +212,19 @@ static int rt_mutex_adjust_prio_chain(st
if (!waiter || !waiter->task)
goto out_unlock_pi;
+ /*
+ * Check the orig_waiter state. After we dropped the locks,
+ * the previous owner of the lock might have released the lock
+ * and made us the pending owner:
+ */
+ if (orig_waiter && !orig_waiter->task)
+ goto out_unlock_pi;
+
+ /*
+ * Drop out, when the task has no waiters. Note,
+ * top_waiter can be NULL, when we are in the deboosting
+ * mode!
+ */
if (top_waiter && (!task_has_pi_waiters(task) ||
top_waiter != task_top_pi_waiter(task)))
goto out_unlock_pi;
--
-
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