1 files changed, 6 insertions, 1 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 7bdc9c9c231b..c4efaa97280c 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -810,8 +810,13 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32
         fl6.flowi6_proto = IPPROTO_TCP;
         if (rt6_need_strict(&fl6.daddr) && !oif)
                 fl6.flowi6_oif = tcp_v6_iif(skb);
-        else
+        else {
+                if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
+                        oif = skb->skb_iif;
+
                 fl6.flowi6_oif = oif;
+        }
+
         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
         fl6.fl6_dport = t1->dest;
         fl6.fl6_sport = t1->source;