Index: sys/external/bsd/drm2/linux/linux_work.c
===================================================================
RCS file: /cvsroot/src/sys/external/bsd/drm2/linux/linux_work.c,v
retrieving revision 1.4
diff -p -u -r1.4 linux_work.c
--- sys/external/bsd/drm2/linux/linux_work.c	16 Jul 2014 20:59:58 -0000	1.4
+++ sys/external/bsd/drm2/linux/linux_work.c	25 Jul 2014 12:59:52 -0000
@@ -293,11 +293,13 @@ static void
 linux_work_lock(struct work_struct *work)
 {
 	__cpu_simple_lock(&work->w_lock);
+	membar_enter();
 }
 
 static void
 linux_work_unlock(struct work_struct *work)
 {
+	membar_exit();
 	__cpu_simple_unlock(&work->w_lock);
 }