diff --git a/[refs] b/[refs]
index bd856b8ec76c..15ad05aaf774 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4c62abc90bea439a4b50aad9f67a310fb9c392e1
+refs/heads/master: 18fec7d8758dd416904da205375e6fa667defc80
diff --git a/trunk/include/linux/rcutree.h b/trunk/include/linux/rcutree.h
index 67458468f1a8..73e7195f9997 100644
--- a/trunk/include/linux/rcutree.h
+++ b/trunk/include/linux/rcutree.h
@@ -83,6 +83,7 @@ extern void rcu_sched_force_quiescent_state(void);
 /* A context switch is a grace period for RCU-sched and RCU-bh. */
 static inline int rcu_blocking_is_gp(void)
 {
+	might_sleep();  /* Check for RCU read-side critical section. */
 	return num_online_cpus() == 1;
 }