diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index e6e65f79ade82132e1a2e5578ba01f43aed15140..0edb07185c255d94e9260eaa192d3ac1c05b5f4a 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3098,7 +3098,8 @@ static void tcp_ack_tstamp(struct sock *sk, struct sk_buff *skb,
 
 	shinfo = skb_shinfo(skb);
 	if ((shinfo->tx_flags & SKBTX_ACK_TSTAMP) &&
-	    between(shinfo->tskey, prior_snd_una, tcp_sk(sk)->snd_una - 1))
+	    !before(shinfo->tskey, prior_snd_una) &&
+	    before(shinfo->tskey, tcp_sk(sk)->snd_una))
 		__skb_tstamp_tx(skb, NULL, sk, SCM_TSTAMP_ACK);
 }