The patch titled
rt-mutex: fix chain walk early wakeup bug
has been added to the -mm tree. Its filename is
rt-mutex-fix-chain-walk-early-wakeup-bug.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: rt-mutex: fix chain walk early wakeup bug
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Alexey Kuznetsov <kuznet@xxxxxxxxxxxxx>
Cc: Ulrich Drepper <drepper@xxxxxxxxxx>
Cc: Eric Dumazet <dada1@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/rtmutex.c | 13 +++++++++++++
1 files changed, 13 insertions(+)
diff -puN kernel/rtmutex.c~rt-mutex-fix-chain-walk-early-wakeup-bug kernel/rtmutex.c
--- a/kernel/rtmutex.c~rt-mutex-fix-chain-walk-early-wakeup-bug
+++ a/kernel/rtmutex.c
@@ -189,6 +189,19 @@ int rt_mutex_adjust_prio_chain(struct ta
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;
_
Patches currently in -mm which might be from tglx@xxxxxxxxxxxxx are
rt-mutex-fix-stale-return-value.patch
rt-mutex-fix-chain-walk-early-wakeup-bug.patch
pi-futex-fix-exit-races-and-locking-problems.patch
git-acpi-add-exports.patch
git-arm.patch
s390-spinlock-initializer-cleanup.patch
i386-hpet-check-if-the-counter-works.patch
remove-clockevents_releaserequest_device.patch
add-a-flag-to-indicate-deferrable-timers-in-proc-timer_stats.patch
lguest-the-host-code-use-hrtimers.patch
futex-tidy-up-the-code.patch
-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
