diff --git a/[refs] b/[refs]
index 8de37e658de3..ab5ea7074455 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 5c879d2094946081af934739850c7260e8b25d3c
+refs/heads/master: c5ae7d41927dbd208c885d4794e30617ad6cdf12
diff --git a/trunk/net/ipv4/route.c b/trunk/net/ipv4/route.c
index 24fd4c596643..82cf2a722b23 100644
--- a/trunk/net/ipv4/route.c
+++ b/trunk/net/ipv4/route.c
@@ -934,12 +934,14 @@ static u32 __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
 	if (mtu < ip_rt_min_pmtu)
 		mtu = ip_rt_min_pmtu;
 
+	rcu_read_lock();
 	if (fib_lookup(dev_net(rt->dst.dev), fl4, &res) == 0) {
 		struct fib_nh *nh = &FIB_RES_NH(res);
 
 		update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
 				      jiffies + ip_rt_mtu_expires);
 	}
+	rcu_read_unlock();
 	return mtu;
 }