Patch "futex: Drop refcount if requeue_pi() acquired the rtmutex" has been added to the 3.10-stable tree

This is a note to let you know that I've just added the patch titled

futex: Drop refcount if requeue_pi() acquired the rtmutex

to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
futex-drop-refcount-if-requeue_pi-acquired-the-rtmutex.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Thomas Gleixner <[email protected]>
Date: Sat, 19 Dec 2015 20:07:38 +0000
Subject: futex: Drop refcount if requeue_pi() acquired the rtmutex

From: Thomas Gleixner <[email protected]>

commit fb75a4282d0d9a3c7c44d940582c2d226cf3acfb upstream.

If the proxy lock in the requeue loop acquires the rtmutex for a waiter then it acquired also refcount on the pi_state related to the futex, but the waiter side does not drop the reference count.

Add the missing free_pi_state() call.

---
 kernel/futex.c |    5 +++++
 1 file changed, 5 insertions(+)

@@ -2494,6 +2494,11 @@ static int futex_wait_requeue_pi(u32 __u
 		if (q.pi_state && (q.pi_state->owner != current)) {
 			spin_lock(q.lock_ptr);
 			ret = fixup_pi_state_owner(uaddr2, &q, current);
+			/*
+			 * Drop the reference to the pi state which
+			 * the requeue_pi() code acquired for us.
+			 */
+			free_pi_state(q.pi_state);
 			spin_unlock(q.lock_ptr);
 		}
 	} else {

Patches currently in stable-queue which might be from [email protected] are

queue-3.10/x86-asm-irq-stop-relying-on-magic-jmp-behavior-for-early_idt_handlers.patch queue-3.10/futex-drop-refcount-if-requeue_pi-acquired-the-rtmutex.patch queue-3.10/perf-fix-inherited-events-vs.-tracepoint-filters.patch