diff --git a/[refs] b/[refs]
index add000f723fe..1a1cf051299b 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b9d86585dc6c9265aa373c7036458fe8aa7627c6
+refs/heads/master: f577111302677e6d1448475821cc19ba8835f60e
diff --git a/trunk/net/ipv4/tcp_input.c b/trunk/net/ipv4/tcp_input.c
index 901240f40688..26713e5d89db 100644
--- a/trunk/net/ipv4/tcp_input.c
+++ b/trunk/net/ipv4/tcp_input.c
@@ -1511,7 +1511,8 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
 
 	tcp_verify_left_out(tp);
 
-	if ((reord < tp->fackets_out) && icsk->icsk_ca_state != TCP_CA_Loss &&
+	if ((reord < tp->fackets_out) &&
+	    ((icsk->icsk_ca_state != TCP_CA_Loss) || tp->undo_marker) &&
 	    (!tp->frto_highmark || after(tp->snd_una, tp->frto_highmark)))
 		tcp_update_reordering(sk, tp->fackets_out - reord, 0);