diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index db47ac24d057..563d016e7478 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -198,6 +198,11 @@ static void tcp_reinit_congestion_control(struct sock *sk,
 	icsk->icsk_ca_setsockopt = 1;
 	memset(icsk->icsk_ca_priv, 0, sizeof(icsk->icsk_ca_priv));
 
+	if (ca->flags & TCP_CONG_NEEDS_ECN)
+		INET_ECN_xmit(sk);
+	else
+		INET_ECN_dontxmit(sk);
+
 	if (!((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
 		tcp_init_congestion_control(sk);
 }
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 7352c097ae48..25d35a56ceba 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -981,7 +981,8 @@ static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
 	skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
 
 	tos = sock_net(sk)->ipv4.sysctl_tcp_reflect_tos ?
-			tcp_rsk(req)->syn_tos : inet_sk(sk)->tos;
+			tcp_rsk(req)->syn_tos & ~INET_ECN_MASK :
+			inet_sk(sk)->tos;
 
 	if (skb) {
 		__tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
@@ -990,7 +991,7 @@ static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
 		err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
 					    ireq->ir_rmt_addr,
 					    rcu_dereference(ireq->ireq_opt),
-					    tos & ~INET_ECN_MASK);
+					    tos);
 		rcu_read_unlock();
 		err = net_xmit_eval(err);
 	}
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 8db59f4e5f13..3d49e8d0afee 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -530,12 +530,12 @@ static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
 		rcu_read_lock();
 		opt = ireq->ipv6_opt;
 		tclass = sock_net(sk)->ipv4.sysctl_tcp_reflect_tos ?
-				tcp_rsk(req)->syn_tos : np->tclass;
+				tcp_rsk(req)->syn_tos & ~INET_ECN_MASK :
+				np->tclass;
 		if (!opt)
 			opt = rcu_dereference(np->opt);
 		err = ip6_xmit(sk, skb, fl6, sk->sk_mark, opt,
-			       tclass & ~INET_ECN_MASK,
-			       sk->sk_priority);
+			       tclass, sk->sk_priority);
 		rcu_read_unlock();
 		err = net_xmit_eval(err);
 	}