Date:	Fri, 15 Nov 2013 17:30:08 +0100
From:	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	Mike Galbraith <bitbucket@...ine.de>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Peter Zijlstra <peterz@...radead.org>,
	LKML <linux-kernel@...r.kernel.org>,
	RT <linux-rt-users@...r.kernel.org>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH] rtmutex: take the waiter lock with irqs off

Mike Galbraith captered the following:
| >#11 [ffff88017b243e90] _raw_spin_lock at ffffffff815d2596
| >#12 [ffff88017b243e90] rt_mutex_trylock at ffffffff815d15be
| >#13 [ffff88017b243eb0] get_next_timer_interrupt at ffffffff81063b42
| >#14 [ffff88017b243f00] tick_nohz_stop_sched_tick at ffffffff810bd1fd
| >#15 [ffff88017b243f70] tick_nohz_irq_exit at ffffffff810bd7d2
| >#16 [ffff88017b243f90] irq_exit at ffffffff8105b02d
| >#17 [ffff88017b243fb0] reschedule_interrupt at ffffffff815db3dd
| >--- <IRQ stack> ---
| >#18 [ffff88017a2a9bc8] reschedule_interrupt at ffffffff815db3dd
| >    [exception RIP: task_blocks_on_rt_mutex+51]
| >#19 [ffff88017a2a9ce0] rt_spin_lock_slowlock at ffffffff815d183c
| >#20 [ffff88017a2a9da0] lock_timer_base.isra.35 at ffffffff81061cbf
| >#21 [ffff88017a2a9dd0] schedule_timeout at ffffffff815cf1ce
| >#22 [ffff88017a2a9e50] rcu_gp_kthread at ffffffff810f9bbb
| >#23 [ffff88017a2a9ed0] kthread at ffffffff810796d5
| >#24 [ffff88017a2a9f50] ret_from_fork at ffffffff815da04c

lock_timer_base() does a try_lock() which deadlocks on the waiter lock
not the lock itself.
This patch makes sure all users of the waiter_lock take the lock with
interrupts off so a try_lock from irq context is possible.

rt_spin_lock_slowlock() uses _irqsave() instead of _irq() because during
system boot it seems to be called a few times with irqs disabled.

Reported-by: <Mike Galbraith <bitbucket@...ine.de>>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
 kernel/futex.c   |  16 +++---
 kernel/rtmutex.c | 156 +++++++++++++++++++++++++++++--------------------------
 2 files changed, 89 insertions(+), 83 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index 0ef419d..404d0bd 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -891,7 +891,7 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this)
 	if (pi_state->owner != current)
 		return -EINVAL;
 
-	raw_spin_lock(&pi_state->pi_mutex.wait_lock);
+	raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
 	new_owner = rt_mutex_next_owner(&pi_state->pi_mutex);
 
 	/*
@@ -917,21 +917,21 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this)
 		else if (curval != uval)
 			ret = -EINVAL;
 		if (ret) {
-			raw_spin_unlock(&pi_state->pi_mutex.wait_lock);
+			raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
 			return ret;
 		}
 	}
 
-	raw_spin_lock_irq(&pi_state->owner->pi_lock);
+	raw_spin_lock(&pi_state->owner->pi_lock);
 	WARN_ON(list_empty(&pi_state->list));
 	list_del_init(&pi_state->list);
-	raw_spin_unlock_irq(&pi_state->owner->pi_lock);
+	raw_spin_unlock(&pi_state->owner->pi_lock);
 
-	raw_spin_lock_irq(&new_owner->pi_lock);
+	raw_spin_lock(&new_owner->pi_lock);
 	WARN_ON(!list_empty(&pi_state->list));
 	list_add(&pi_state->list, &new_owner->pi_state_list);
 	pi_state->owner = new_owner;
-	raw_spin_unlock_irq(&new_owner->pi_lock);
+	raw_spin_unlock(&new_owner->pi_lock);
 
 	raw_spin_unlock(&pi_state->pi_mutex.wait_lock);
 	rt_mutex_unlock(&pi_state->pi_mutex);
@@ -1762,11 +1762,11 @@ static int fixup_owner(u32 __user *uaddr, struct futex_q *q, int locked)
 		 * we returned due to timeout or signal without taking the
 		 * rt_mutex. Too late.
 		 */
-		raw_spin_lock(&q->pi_state->pi_mutex.wait_lock);
+		raw_spin_lock_irq(&q->pi_state->pi_mutex.wait_lock);
 		owner = rt_mutex_owner(&q->pi_state->pi_mutex);
 		if (!owner)
 			owner = rt_mutex_next_owner(&q->pi_state->pi_mutex);
-		raw_spin_unlock(&q->pi_state->pi_mutex.wait_lock);
+		raw_spin_unlock_irq(&q->pi_state->pi_mutex.wait_lock);
 		ret = fixup_pi_state_owner(uaddr, q, owner);
 		goto out;
 	}
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index b4c651e..d2d4a33 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -298,7 +298,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
 	plist_add(&waiter->list_entry, &lock->wait_list);
 
 	/* Release the task */
-	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+	raw_spin_unlock(&task->pi_lock);
 	if (!rt_mutex_owner(lock)) {
 		struct rt_mutex_waiter *lock_top_waiter;
 
@@ -309,7 +309,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
 		lock_top_waiter = rt_mutex_top_waiter(lock);
 		if (top_waiter != lock_top_waiter)
 			rt_mutex_wake_waiter(lock_top_waiter);
-		raw_spin_unlock(&lock->wait_lock);
+		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 		goto out_put_task;
 	}
 	put_task_struct(task);
@@ -317,7 +317,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
 	/* Grab the next task */
 	task = rt_mutex_owner(lock);
 	get_task_struct(task);
-	raw_spin_lock_irqsave(&task->pi_lock, flags);
+	raw_spin_lock(&task->pi_lock);
 
 	if (waiter == rt_mutex_top_waiter(lock)) {
 		/* Boost the owner */
@@ -335,10 +335,10 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
 		__rt_mutex_adjust_prio(task);
 	}
 
-	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+	raw_spin_unlock(&task->pi_lock);
 
 	top_waiter = rt_mutex_top_waiter(lock);
-	raw_spin_unlock(&lock->wait_lock);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 	if (!detect_deadlock && waiter != top_waiter)
 		goto out_put_task;
@@ -425,10 +425,9 @@ __try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
 	/* We got the lock. */
 
 	if (waiter || rt_mutex_has_waiters(lock)) {
-		unsigned long flags;
 		struct rt_mutex_waiter *top;
 
-		raw_spin_lock_irqsave(&task->pi_lock, flags);
+		raw_spin_lock(&task->pi_lock);
 
 		/* remove the queued waiter. */
 		if (waiter) {
@@ -445,7 +444,7 @@ __try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
 			top->pi_list_entry.prio = top->list_entry.prio;
 			plist_add(&top->pi_list_entry, &task->pi_waiters);
 		}
-		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+		raw_spin_unlock(&task->pi_lock);
 	}
 
 	debug_rt_mutex_lock(lock);
@@ -474,14 +473,13 @@ try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
 static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
 				   struct rt_mutex_waiter *waiter,
 				   struct task_struct *task,
-				   int detect_deadlock)
+				   int detect_deadlock, unsigned long *flags)
 {
 	struct task_struct *owner = rt_mutex_owner(lock);
 	struct rt_mutex_waiter *top_waiter = waiter;
-	unsigned long flags;
 	int chain_walk = 0, res;
 
-	raw_spin_lock_irqsave(&task->pi_lock, flags);
+	raw_spin_lock(&task->pi_lock);
 
 	/*
 	 * In the case of futex requeue PI, this will be a proxy
@@ -493,7 +491,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
 	 * the task if PI_WAKEUP_INPROGRESS is set.
 	 */
 	if (task != current && task->pi_blocked_on == PI_WAKEUP_INPROGRESS) {
-		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+		raw_spin_unlock(&task->pi_lock);
 		return -EAGAIN;
 	}
 
@@ -512,20 +510,20 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
 
 	task->pi_blocked_on = waiter;
 
-	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+	raw_spin_unlock(&task->pi_lock);
 
 	if (!owner)
 		return 0;
 
 	if (waiter == rt_mutex_top_waiter(lock)) {
-		raw_spin_lock_irqsave(&owner->pi_lock, flags);
+		raw_spin_lock(&owner->pi_lock);
 		plist_del(&top_waiter->pi_list_entry, &owner->pi_waiters);
 		plist_add(&waiter->pi_list_entry, &owner->pi_waiters);
 
 		__rt_mutex_adjust_prio(owner);
 		if (rt_mutex_real_waiter(owner->pi_blocked_on))
 			chain_walk = 1;
-		raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
+		raw_spin_unlock(&owner->pi_lock);
 	}
 	else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock))
 		chain_walk = 1;
@@ -540,12 +538,12 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
 	 */
 	get_task_struct(owner);
 
-	raw_spin_unlock(&lock->wait_lock);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, *flags);
 
 	res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock, waiter,
 					 task);
 
-	raw_spin_lock(&lock->wait_lock);
+	raw_spin_lock_irqsave(&lock->wait_lock, *flags);
 
 	return res;
 }
@@ -560,9 +558,8 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
 static void wakeup_next_waiter(struct rt_mutex *lock)
 {
 	struct rt_mutex_waiter *waiter;
-	unsigned long flags;
 
-	raw_spin_lock_irqsave(&current->pi_lock, flags);
+	raw_spin_lock(&current->pi_lock);
 
 	waiter = rt_mutex_top_waiter(lock);
 
@@ -576,7 +573,7 @@ static void wakeup_next_waiter(struct rt_mutex *lock)
 
 	rt_mutex_set_owner(lock, NULL);
 
-	raw_spin_unlock_irqrestore(&current->pi_lock, flags);
+	raw_spin_unlock(&current->pi_lock);
 
 	rt_mutex_wake_waiter(waiter);
 }
@@ -588,24 +585,24 @@ static void wakeup_next_waiter(struct rt_mutex *lock)
  * have just failed to try_to_take_rt_mutex().
  */
 static void remove_waiter(struct rt_mutex *lock,
-			  struct rt_mutex_waiter *waiter)
+			  struct rt_mutex_waiter *waiter,
+			  unsigned long *flags)
 {
 	int first = (waiter == rt_mutex_top_waiter(lock));
 	struct task_struct *owner = rt_mutex_owner(lock);
-	unsigned long flags;
 	int chain_walk = 0;
 
-	raw_spin_lock_irqsave(&current->pi_lock, flags);
+	raw_spin_lock(&current->pi_lock);
 	plist_del(&waiter->list_entry, &lock->wait_list);
 	current->pi_blocked_on = NULL;
-	raw_spin_unlock_irqrestore(&current->pi_lock, flags);
+	raw_spin_unlock(&current->pi_lock);
 
 	if (!owner)
 		return;
 
 	if (first) {
 
-		raw_spin_lock_irqsave(&owner->pi_lock, flags);
+		raw_spin_lock(&owner->pi_lock);
 
 		plist_del(&waiter->pi_list_entry, &owner->pi_waiters);
 
@@ -620,7 +617,7 @@ static void remove_waiter(struct rt_mutex *lock,
 		if (rt_mutex_real_waiter(owner->pi_blocked_on))
 			chain_walk = 1;
 
-		raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
+		raw_spin_unlock(&owner->pi_lock);
 	}
 
 	WARN_ON(!plist_node_empty(&waiter->pi_list_entry));
@@ -631,11 +628,11 @@ static void remove_waiter(struct rt_mutex *lock,
 	/* gets dropped in rt_mutex_adjust_prio_chain()! */
 	get_task_struct(owner);
 
-	raw_spin_unlock(&lock->wait_lock);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, *flags);
 
 	rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current);
 
-	raw_spin_lock(&lock->wait_lock);
+	raw_spin_lock_irqsave(&lock->wait_lock, *flags);
 }
 
 /*
@@ -723,9 +720,6 @@ static int adaptive_wait(struct rt_mutex *lock,
 }
 #endif
 
-# define pi_lock(lock)			raw_spin_lock_irq(lock)
-# define pi_unlock(lock)		raw_spin_unlock_irq(lock)
-
 /*
  * Slow path lock function spin_lock style: this variant is very
  * careful not to miss any non-lock wakeups.
@@ -737,15 +731,16 @@ static void  noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
 {
 	struct task_struct *lock_owner, *self = current;
 	struct rt_mutex_waiter waiter, *top_waiter;
+	unsigned long flags;
 	int ret;
 
 	rt_mutex_init_waiter(&waiter, true);
 
-	raw_spin_lock(&lock->wait_lock);
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
 	init_lists(lock);
 
 	if (__try_to_take_rt_mutex(lock, self, NULL, STEAL_LATERAL)) {
-		raw_spin_unlock(&lock->wait_lock);
+		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 		return;
 	}
 
@@ -757,12 +752,12 @@ static void  noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
 	 * as well. We are serialized via pi_lock against wakeups. See
 	 * try_to_wake_up().
 	 */
-	pi_lock(&self->pi_lock);
+	raw_spin_lock(&self->pi_lock);
 	self->saved_state = self->state;
 	__set_current_state(TASK_UNINTERRUPTIBLE);
-	pi_unlock(&self->pi_lock);
+	raw_spin_unlock(&self->pi_lock);
 
-	ret = task_blocks_on_rt_mutex(lock, &waiter, self, 0);
+	ret = task_blocks_on_rt_mutex(lock, &waiter, self, 0, &flags);
 	BUG_ON(ret);
 
 	for (;;) {
@@ -773,18 +768,18 @@ static void  noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
 		top_waiter = rt_mutex_top_waiter(lock);
 		lock_owner = rt_mutex_owner(lock);
 
-		raw_spin_unlock(&lock->wait_lock);
+		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 		debug_rt_mutex_print_deadlock(&waiter);
 
 		if (top_waiter != &waiter || adaptive_wait(lock, lock_owner))
 			schedule_rt_mutex(lock);
 
-		raw_spin_lock(&lock->wait_lock);
+		raw_spin_lock_irqsave(&lock->wait_lock, flags);
 
-		pi_lock(&self->pi_lock);
+		raw_spin_lock(&self->pi_lock);
 		__set_current_state(TASK_UNINTERRUPTIBLE);
-		pi_unlock(&self->pi_lock);
+		raw_spin_unlock(&self->pi_lock);
 	}
 
 	/*
@@ -794,10 +789,10 @@ static void  noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
 	 * happened while we were blocked. Clear saved_state so
 	 * try_to_wakeup() does not get confused.
 	 */
-	pi_lock(&self->pi_lock);
+	raw_spin_lock(&self->pi_lock);
 	__set_current_state(self->saved_state);
 	self->saved_state = TASK_RUNNING;
-	pi_unlock(&self->pi_lock);
+	raw_spin_unlock(&self->pi_lock);
 
 	/*
 	 * try_to_take_rt_mutex() sets the waiter bit
@@ -808,7 +803,7 @@ static void  noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
 	BUG_ON(rt_mutex_has_waiters(lock) && &waiter == rt_mutex_top_waiter(lock));
 	BUG_ON(!plist_node_empty(&waiter.list_entry));
 
-	raw_spin_unlock(&lock->wait_lock);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 	debug_rt_mutex_free_waiter(&waiter);
 }
@@ -818,7 +813,9 @@ static void  noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
  */
 static void  noinline __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
 {
-	raw_spin_lock(&lock->wait_lock);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
 
 	debug_rt_mutex_unlock(lock);
 
@@ -826,13 +823,13 @@ static void  noinline __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
 
 	if (!rt_mutex_has_waiters(lock)) {
 		lock->owner = NULL;
-		raw_spin_unlock(&lock->wait_lock);
+		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 		return;
 	}
 
 	wakeup_next_waiter(lock);
 
-	raw_spin_unlock(&lock->wait_lock);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 	/* Undo pi boosting.when necessary */
 	rt_mutex_adjust_prio(current);
@@ -1003,7 +1000,8 @@ static int __sched
 __rt_mutex_slowlock(struct rt_mutex *lock, int state,
 		    struct hrtimer_sleeper *timeout,
 		    struct rt_mutex_waiter *waiter,
-		    struct ww_acquire_ctx *ww_ctx)
+		    struct ww_acquire_ctx *ww_ctx,
+		    unsigned long *flags)
 {
 	int ret = 0;
 
@@ -1032,13 +1030,13 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
 				break;
 		}
 
-		raw_spin_unlock(&lock->wait_lock);
+		raw_spin_unlock_irqrestore(&lock->wait_lock, *flags);
 
 		debug_rt_mutex_print_deadlock(waiter);
 
 		schedule_rt_mutex(lock);
 
-		raw_spin_lock(&lock->wait_lock);
+		raw_spin_lock_irqsave(&lock->wait_lock, *flags);
 		set_current_state(state);
 	}
 
@@ -1130,18 +1128,19 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 		  int detect_deadlock, struct ww_acquire_ctx *ww_ctx)
 {
 	struct rt_mutex_waiter waiter;
+	unsigned long flags;
 	int ret = 0;
 
 	rt_mutex_init_waiter(&waiter, false);
 
-	raw_spin_lock(&lock->wait_lock);
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
 	init_lists(lock);
 
 	/* Try to acquire the lock again: */
 	if (try_to_take_rt_mutex(lock, current, NULL)) {
 		if (ww_ctx)
 			ww_mutex_account_lock(lock, ww_ctx);
-		raw_spin_unlock(&lock->wait_lock);
+		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 		return 0;
 	}
 
@@ -1154,15 +1153,17 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 			timeout->task = NULL;
 	}
 
-	ret = task_blocks_on_rt_mutex(lock, &waiter, current, detect_deadlock);
+	ret = task_blocks_on_rt_mutex(lock, &waiter, current, detect_deadlock,
+			&flags);
 
 	if (likely(!ret))
-		ret = __rt_mutex_slowlock(lock, state, timeout, &waiter, ww_ctx);
+		ret = __rt_mutex_slowlock(lock, state, timeout, &waiter, ww_ctx,
+				&flags);
 
 	set_current_state(TASK_RUNNING);
 
 	if (unlikely(ret))
-		remove_waiter(lock, &waiter);
+		remove_waiter(lock, &waiter, &flags);
 	else if (ww_ctx)
 		ww_mutex_account_lock(lock, ww_ctx);
 
@@ -1172,7 +1173,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 	 */
 	fixup_rt_mutex_waiters(lock);
 
-	raw_spin_unlock(&lock->wait_lock);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 	/* Remove pending timer: */
 	if (unlikely(timeout))
@@ -1189,9 +1190,10 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 static inline int
 rt_mutex_slowtrylock(struct rt_mutex *lock)
 {
+	unsigned long flags;
 	int ret = 0;
 
-	raw_spin_lock(&lock->wait_lock);
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
 	init_lists(lock);
 
 	if (likely(rt_mutex_owner(lock) != current)) {
@@ -1204,7 +1206,7 @@ rt_mutex_slowtrylock(struct rt_mutex *lock)
 		fixup_rt_mutex_waiters(lock);
 	}
 
-	raw_spin_unlock(&lock->wait_lock);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 	return ret;
 }
@@ -1215,7 +1217,9 @@ rt_mutex_slowtrylock(struct rt_mutex *lock)
 static void __sched
 rt_mutex_slowunlock(struct rt_mutex *lock)
 {
-	raw_spin_lock(&lock->wait_lock);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
 
 	debug_rt_mutex_unlock(lock);
 
@@ -1223,13 +1227,13 @@ rt_mutex_slowunlock(struct rt_mutex *lock)
 
 	if (!rt_mutex_has_waiters(lock)) {
 		lock->owner = NULL;
-		raw_spin_unlock(&lock->wait_lock);
+		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 		return;
 	}
 
 	wakeup_next_waiter(lock);
 
-	raw_spin_unlock(&lock->wait_lock);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 	/* Undo pi boosting if necessary: */
 	rt_mutex_adjust_prio(current);
@@ -1487,12 +1491,13 @@ int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
 			      struct rt_mutex_waiter *waiter,
 			      struct task_struct *task, int detect_deadlock)
 {
+	unsigned long flags;
 	int ret;
 
-	raw_spin_lock(&lock->wait_lock);
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
 
 	if (try_to_take_rt_mutex(lock, task, NULL)) {
-		raw_spin_unlock(&lock->wait_lock);
+		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 		return 1;
 	}
 
@@ -1515,18 +1520,18 @@ 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_irq(&task->pi_lock);
+	raw_spin_lock(&task->pi_lock);
 	if (task->pi_blocked_on) {
-		raw_spin_unlock_irq(&task->pi_lock);
-		raw_spin_unlock(&lock->wait_lock);
+		raw_spin_unlock(&task->pi_lock);
+		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 		return -EAGAIN;
 	}
 	task->pi_blocked_on = PI_REQUEUE_INPROGRESS;
-	raw_spin_unlock_irq(&task->pi_lock);
+	raw_spin_unlock(&task->pi_lock);
 #endif
 
-	ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock);
-
+	ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock,
+			&flags);
 	if (ret && !rt_mutex_owner(lock)) {
 		/*
 		 * Reset the return value. We might have
@@ -1538,9 +1543,9 @@ int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
 	}
 
 	if (unlikely(ret))
-		remove_waiter(lock, waiter);
+		remove_waiter(lock, waiter, &flags);
 
-	raw_spin_unlock(&lock->wait_lock);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 	debug_rt_mutex_print_deadlock(waiter);
 
@@ -1589,17 +1594,18 @@ int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
 			       int detect_deadlock)
 {
 	int ret;
+	unsigned long flags;
 
-	raw_spin_lock(&lock->wait_lock);
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
 
 	set_current_state(TASK_INTERRUPTIBLE);
 
-	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter, NULL);
-
+	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter, NULL,
+			&flags);
 	set_current_state(TASK_RUNNING);
 
 	if (unlikely(ret))
-		remove_waiter(lock, waiter);
+		remove_waiter(lock, waiter, &flags);
 
 	/*
 	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
@@ -1607,7 +1613,7 @@ int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
 	 */
 	fixup_rt_mutex_waiters(lock);
 
-	raw_spin_unlock(&lock->wait_lock);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 	return ret;
 }
-- 
1.8.4.2

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