diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index caf3c41..511b738 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -127,7 +127,7 @@
 	/* skb->len may jitter because of SACKs, even if peer
 	 * sends good full-sized frames.
 	 */
-	len = skb->len;
+	len = skb_shinfo(skb)->gso_size ?: skb->len;
 	if (len >= icsk->icsk_ack.rcv_mss) {
 		icsk->icsk_ack.rcv_mss = len;
 	} else {