diff --git a/[refs] b/[refs]
index 18ff8c0ea671..ebe40e12a7dc 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c57afe80db4e169135eb675acc2d241e26cc064e
+refs/heads/master: 79b9a75fb703b6a2670e46b9dc495af5bc7029b3
diff --git a/trunk/kernel/rcutree_plugin.h b/trunk/kernel/rcutree_plugin.h
index 50c17975d4f4..ad61da79b311 100644
--- a/trunk/kernel/rcutree_plugin.h
+++ b/trunk/kernel/rcutree_plugin.h
@@ -2065,6 +2065,7 @@ static bool rcu_cpu_has_nonlazy_callbacks(int cpu)
  */
 static void rcu_idle_gp_timer_func(unsigned long unused)
 {
+	WARN_ON_ONCE(1); /* Getting here can hang the system... */
 	trace_rcu_prep_idle("Timer");
 }