diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index bb8f547..5f29b2e 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -822,8 +822,11 @@
 							   &md5);
 	tcp_header_size = tcp_options_size + sizeof(struct tcphdr);
 
-	if (tcp_packets_in_flight(tp) == 0)
+	if (tcp_packets_in_flight(tp) == 0) {
 		tcp_ca_event(sk, CA_EVENT_TX_START);
+		skb->ooo_okay = 1;
+	} else
+		skb->ooo_okay = 0;
 
 	skb_push(skb, tcp_header_size);
 	skb_reset_transport_header(skb);