diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 2f6d8f57fdd4..1cb8954885ec 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1420,8 +1420,12 @@ EXPORT_SYMBOL_GPL(ip6_update_pmtu);
 
 void ip6_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, __be32 mtu)
 {
-	ip6_update_pmtu(skb, sock_net(sk), mtu,
-			sk->sk_bound_dev_if, sk->sk_mark);
+	int oif = sk->sk_bound_dev_if;
+
+	if (!oif && skb->dev)
+		oif = l3mdev_master_ifindex(skb->dev);
+
+	ip6_update_pmtu(skb, sock_net(sk), mtu, oif, sk->sk_mark);
 }
 EXPORT_SYMBOL_GPL(ip6_sk_update_pmtu);