diff --git a/include/net/tcp.h b/include/net/tcp.h
index cfb55e1..54285ba 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1390,6 +1390,8 @@
 {
 	if (sk->sk_send_head == skb_unlinked)
 		sk->sk_send_head = NULL;
+	if (tcp_sk(sk)->highest_sack == skb_unlinked)
+		tcp_sk(sk)->highest_sack = NULL;
 }
 
 static inline void tcp_init_send_head(struct sock *sk)