From a4d7993d84c6daea2f4f5586ca79b5450831df51 Mon Sep 17 00:00:00 2001
From: Steven Rostedt <rostedt@goodmis.org>
Date: Thu, 1 Mar 2012 13:55:29 -0500
Subject: [PATCH 232/274] futex/rt: Fix possible lockup when taking pi_lock in
 proxy handler

When taking the pi_lock, we must disable interrupts because the
pi_lock can also be taken in an interrupt handler.

Use raw_spin_lock_irq() instead of raw_spin_lock().

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Carsten Emde <C.Emde@osadl.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Clark Williams <clark.williams@gmail.com>
Cc: stable-rt@vger.kernel.org
Link: http://lkml.kernel.org/r/20120301190345.165160680@goodmis.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/rtmutex.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index 921c90b..3bff726 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -1365,14 +1365,14 @@ int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
 	 * PI_REQUEUE_INPROGRESS, so that if the task is waking up
 	 * it will know that we are in the process of requeuing it.
 	 */
-	raw_spin_lock(&task->pi_lock);
+	raw_spin_lock_irq(&task->pi_lock);
 	if (task->pi_blocked_on) {
-		raw_spin_unlock(&task->pi_lock);
+		raw_spin_unlock_irq(&task->pi_lock);
 		raw_spin_unlock(&lock->wait_lock);
 		return -EAGAIN;
 	}
 	task->pi_blocked_on = PI_REQUEUE_INPROGRESS;
-	raw_spin_unlock(&task->pi_lock);
+	raw_spin_unlock_irq(&task->pi_lock);
 #endif
 
 	ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock);
-- 
1.7.10.4