diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 019c2389a341..2ca6c080a4bc 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -95,6 +95,7 @@ void tcp_init_congestion_control(struct sock *sk)
 		rcu_read_unlock();
 	}
 
+	tcp_sk(sk)->prior_ssthresh = 0;
 	if (icsk->icsk_ca_ops->init)
 		icsk->icsk_ca_ops->init(sk);
 }