Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=1a539a87280b3032fd12bc93a4a82f1d8aa97ca8
Commit: 1a539a87280b3032fd12bc93a4a82f1d8aa97ca8
Parent: c0d1d2bf5a28f78def7b68ca1eb5ba31aafd43a1
Author: Thomas Gleixner <[EMAIL PROTECTED]>
AuthorDate: Fri Jun 8 13:46:58 2007 -0700
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Fri Jun 8 17:23:34 2007 -0700
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 <[EMAIL PROTECTED]>
Acked-by: Ingo Molnar <[EMAIL PROTECTED]>
Cc: Steven Rostedt <[EMAIL PROTECTED]>
Cc: Alexey Kuznetsov <[EMAIL PROTECTED]>
Cc: Ulrich Drepper <[EMAIL PROTECTED]>
Cc: Eric Dumazet <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
kernel/rtmutex.c | 13 +++++++++++++
1 files changed, 13 insertions(+), 0 deletions(-)
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index a273183..a6fbb41 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -189,6 +189,19 @@ int rt_mutex_adjust_prio_chain(struct task_struct *task,
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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