futex: Fix WARN_ON() test for UP
Steven Rostedt [Thu, 17 Mar 2011 19:21:07 +0000 (15:21 -0400)]
An update of the futex code had a

WARN_ON(!spin_is_locked(q->lock_ptr))

But on UP, spin_is_locked() is always false, and will
trigger this warning, and even worse, it will exit the function
without doing the necessary work.

Converting this to a WARN_ON_SMP() fixes the problem.

Reported-by: Richard Weinberger <richard@nod.at>
Tested-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <20110317192208.682654502@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/futex.c

index bda4157..823aae3 100644 (file)
@@ -782,8 +782,8 @@ static void __unqueue_futex(struct futex_q *q)
 {
        struct futex_hash_bucket *hb;
 
-       if (WARN_ON(!q->lock_ptr || !spin_is_locked(q->lock_ptr)
-                       || plist_node_empty(&q->list)))
+       if (WARN_ON_SMP(!q->lock_ptr || !spin_is_locked(q->lock_ptr))
+           || WARN_ON(plist_node_empty(&q->list)))
                return;
 
        hb = container_of(q->lock_ptr, struct futex_hash_bucket, lock);