diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index bf7a22412bcb..12de90a5047c 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -648,7 +648,7 @@ static void tcp_v4_send_ack(struct tcp_timewait_sock *twsk,
 				   TCPOLEN_TIMESTAMP);
 		rep.opt[1] = htonl(tcp_time_stamp);
 		rep.opt[2] = htonl(ts);
-		arg.iov[0].iov_len = TCPOLEN_TSTAMP_ALIGNED;
+		arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
 	}
 
 	/* Swap the send and the receive. */