diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -800,7 +800,7 @@
 		return (NULL);
 	}
 
-	solisten_enqueue(so, connstatus);
+	(void)solisten_enqueue(so, connstatus);
 
 	return (so);
 }
@@ -808,8 +808,10 @@
 /*
  * Enqueue socket cloned by solisten_clone() to the listen queue of the
  * listener it has been cloned from.
+ *
+ * Return 'true' if socket landed on complete queue, otherwise 'false'.
  */
-void
+bool
 solisten_enqueue(struct socket *so, int connstatus)
 {
 	struct socket *head = so->so_listen;
@@ -827,6 +829,7 @@
 		so->so_qstate = SQ_COMP;
 		head->sol_qlen++;
 		solisten_wakeup(head);	/* unlocks */
+		return (true);
 	} else {
 		/*
 		 * Keep removing sockets from the head until there's room for
@@ -853,6 +856,7 @@
 		so->so_qstate = SQ_INCOMP;
 		head->sol_incqlen++;
 		SOLISTEN_UNLOCK(head);
+		return (false);
 	}
 }
 
diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -2433,7 +2433,10 @@
 	case TCPS_SYN_RECEIVED:
 
 		TCPSTAT_INC(tcps_connects);
-		soisconnected(so);
+		if (tp->t_flags & TF_INCQUEUE) {
+			tp->t_flags &= ~TF_INCQUEUE;
+			soisconnected(so);
+		}
 		/* Do window scaling? */
 		if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==
 			(TF_RCVD_SCALE|TF_REQ_SCALE)) {
diff --git a/sys/netinet/tcp_syncache.c b/sys/netinet/tcp_syncache.c
--- a/sys/netinet/tcp_syncache.c
+++ b/sys/netinet/tcp_syncache.c
@@ -1039,7 +1039,8 @@
 	TCPSTAT_INC(tcps_accepts);
 	TCP_PROBE6(state__change, NULL, tp, NULL, tp, NULL, TCPS_LISTEN);
 
-	solisten_enqueue(so, SS_ISCONNECTED);
+	if (!solisten_enqueue(so, SS_ISCONNECTED))
+		tp->t_flags |= TF_INCQUEUE;
 
 	return (so);
 
diff --git a/sys/netinet/tcp_usrreq.c b/sys/netinet/tcp_usrreq.c
--- a/sys/netinet/tcp_usrreq.c
+++ b/sys/netinet/tcp_usrreq.c
@@ -2978,8 +2978,8 @@
 		db_printf("%sTF_MORETOCOME", comma ? ", " : "");
 		comma = 1;
 	}
-	if (t_flags & TF_LQ_OVERFLOW) {
-		db_printf("%sTF_LQ_OVERFLOW", comma ? ", " : "");
+	if (t_flags & TF_INCQUEUE) {
+		db_printf("%sTF_INCQUEUE", comma ? ", " : "");
 		comma = 1;
 	}
 	if (t_flags & TF_LASTIDLE) {
diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h
--- a/sys/netinet/tcp_var.h
+++ b/sys/netinet/tcp_var.h
@@ -515,7 +515,7 @@
 #define	TF_WAKESOR	0x00004000	/* wake up receive socket */
 #define	TF_GPUTINPROG	0x00008000	/* Goodput measurement in progress */
 #define	TF_MORETOCOME	0x00010000	/* More data to be appended to sock */
-#define	TF_LQ_OVERFLOW	0x00020000	/* listen queue overflow */
+#define	TF_INCQUEUE	0x00020000	/* on incomplete queue of listener */
 #define	TF_LASTIDLE	0x00040000	/* connection was previously idle */
 #define	TF_RXWIN0SENT	0x00080000	/* sent a receiver win 0 in response */
 #define	TF_FASTRECOVERY	0x00100000	/* in NewReno Fast Recovery */
diff --git a/sys/sys/socketvar.h b/sys/sys/socketvar.h
--- a/sys/sys/socketvar.h
+++ b/sys/sys/socketvar.h
@@ -474,7 +474,7 @@
 void	solisten_proto(struct socket *so, int backlog);
 void	solisten_proto_abort(struct socket *so);
 int	solisten_proto_check(struct socket *so);
-void	solisten_enqueue(struct socket *, int);
+bool	solisten_enqueue(struct socket *, int);
 int	solisten_dequeue(struct socket *, struct socket **, int);
 struct socket *
 	solisten_clone(struct socket *);