diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 075c559570e6ec1fefbd108874049ec1dd5470ee..9550cc42de2d9ba4cca6d961a2a3bca501755a69 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2329,6 +2329,7 @@ static void tcp_undo_cwnd_reduction(struct sock *sk, bool unmark_loss)
 	}
 	tp->snd_cwnd_stamp = tcp_jiffies32;
 	tp->undo_marker = 0;
+	tp->rack.advanced = 1; /* Force RACK to re-exam losses */
 }
 
 static inline bool tcp_may_undo(const struct tcp_sock *tp)