diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index db1e0da871f40a2284d67bd48c0f21d772b923f3..50e1e0feddfcdfcc69d641f27a2bd3596bd56098 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -993,6 +993,9 @@ void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
 	struct flowi4 fl4;
 	struct rtable *rt;
 
+	if (!mark)
+		mark = IP4_REPLY_MARK(net, skb->mark);
+
 	__build_flow_key(&fl4, NULL, iph, oif,
 			 RT_TOS(iph->tos), protocol, mark, flow_flags);
 	rt = __ip_route_output_key(net, &fl4);
@@ -1010,6 +1013,10 @@ static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
 	struct rtable *rt;
 
 	__build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
+
+	if (!fl4.flowi4_mark)
+		fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
+
 	rt = __ip_route_output_key(sock_net(sk), &fl4);
 	if (!IS_ERR(rt)) {
 		__ip_rt_update_pmtu(rt, &fl4, mtu);
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 004fffb6c2218a12a9619eb08f359a8f2b391297..f0a8ff9ed8910aeb6f8ff8c2578bd13ac2c395ea 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1176,7 +1176,7 @@ void ip6_update_pmtu(struct sk_buff *skb, struct net *net, __be32 mtu,
 
 	memset(&fl6, 0, sizeof(fl6));
 	fl6.flowi6_oif = oif;
-	fl6.flowi6_mark = mark;
+	fl6.flowi6_mark = mark ? mark : IP6_REPLY_MARK(net, skb->mark);
 	fl6.daddr = iph->daddr;
 	fl6.saddr = iph->saddr;
 	fl6.flowlabel = ip6_flowinfo(iph);