diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 259cbee..132737a 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -965,7 +965,7 @@ void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
 }
 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
 
-void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
+static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
 {
 	const struct iphdr *iph = (const struct iphdr *) skb->data;
 	struct flowi4 fl4;
@@ -978,6 +978,46 @@ void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
 		ip_rt_put(rt);
 	}
 }
+
+void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
+{
+	const struct iphdr *iph = (const struct iphdr *) skb->data;
+	struct flowi4 fl4;
+	struct rtable *rt;
+	struct dst_entry *dst;
+
+	bh_lock_sock(sk);
+	rt = (struct rtable *) __sk_dst_get(sk);
+
+	if (sock_owned_by_user(sk) || !rt) {
+		__ipv4_sk_update_pmtu(skb, sk, mtu);
+		goto out;
+	}
+
+	__build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
+
+	if (!__sk_dst_check(sk, 0)) {
+		rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
+		if (IS_ERR(rt))
+			goto out;
+	}
+
+	__ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
+
+	dst = dst_check(&rt->dst, 0);
+	if (!dst) {
+		rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
+		if (IS_ERR(rt))
+			goto out;
+
+		dst = &rt->dst;
+	}
+
+	 __sk_dst_set(sk, dst);
+
+out:
+	bh_unlock_sock(sk);
+}
 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
 
 void ipv4_redirect(struct sk_buff *skb, struct net *net,