diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 6e3c512054a6..324c9bcc5456 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -180,6 +180,7 @@ void tcp_init_congestion_control(struct sock *sk)
 {
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 
+	tcp_sk(sk)->prior_ssthresh = 0;
 	if (icsk->icsk_ca_ops->init)
 		icsk->icsk_ca_ops->init(sk);
 	if (tcp_ca_needs_ecn(sk))