futex: Fix bug in WARN_ON for NULL q.pi_state

commit f27071cb upstream.

The WARN_ON in futex_wait_requeue_pi() for a NULL q.pi_state was testing
the address (&q.pi_state) of the pointer instead of the value
(q.pi_state) of the pointer. Correct it accordingly.
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Cc: Dave Jones <davej@redhat.com>
Link: http://lkml.kernel.org/r/1c85d97f6e5f79ec389a4ead3e367363c74bd09a.1342809673.git.dvhart@linux.intel.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

kernel/futex.c

@@ -2343,7 +2343,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
 		 * signal.  futex_unlock_pi() will not destroy the lock_ptr nor
 		 * the pi_state.
 		 */
-		WARN_ON(!&q.pi_state);
+		WARN_ON(!q.pi_state);
 		pi_mutex = &q.pi_state->pi_mutex;
 		ret = rt_mutex_finish_proxy_lock(pi_mutex, to, &rt_waiter, 1);
 		debug_rt_mutex_free_waiter(&rt_waiter);