From: Thomas Gleixner <tglx@linutronix.de>
Date: Sat, 1 Apr 2017 12:50:59 +0200
Subject: rtmutex: Make lock_killable work
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git
Git-commit: 508daaa45c9a99b15b0a7ab37beca6fe4eda4eb6
Patch-mainline: Queued in subsystem maintainer repository
References: SLE Realtime Extension

Locking an rt mutex killable does not work because signal handling is
restricted to TASK_INTERRUPTIBLE.

Use signal_pending_state() unconditionaly.

Cc: rt-stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Mike Galbraith <mgalbraith@suse.de>
---
 kernel/locking/rtmutex.c |   19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1202,18 +1202,13 @@ __rt_mutex_slowlock(struct rt_mutex *loc
 		if (try_to_take_rt_mutex(lock, current, waiter))
 			break;
 
-		/*
-		 * TASK_INTERRUPTIBLE checks for signals and
-		 * timeout. Ignored otherwise.
-		 */
-		if (likely(state == TASK_INTERRUPTIBLE)) {
-			/* Signal pending? */
-			if (signal_pending(current))
-				ret = -EINTR;
-			if (timeout && !timeout->task)
-				ret = -ETIMEDOUT;
-			if (ret)
-				break;
+		if (timeout && !timeout->task) {
+			ret = -ETIMEDOUT;
+			break;
+		}
+		if (signal_pending_state(state, current)) {
+			ret = -EINTR;
+			break;
 		}
 
 		raw_spin_unlock_irq(&lock->wait_lock);