1 files changed, 2 insertions, 1 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 901240f40688..26713e5d89db 100644
--- a/net/ipv4/tcp_input.c
+++ b/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);