--- zzzz-none-000/linux-4.4.60/net/l2tp/l2tp_ip.c	2017-04-08 07:53:53.000000000 +0000
+++ scorpion-1750e-727/linux-4.4.60/net/l2tp/l2tp_ip.c	2021-02-04 17:41:59.000000000 +0000
@@ -122,6 +122,7 @@
 	unsigned char *ptr, *optr;
 	struct l2tp_session *session;
 	struct l2tp_tunnel *tunnel = NULL;
+	struct iphdr *iph;
 	int length;
 
 	if (!pskb_may_pull(skb, 4))
@@ -142,19 +143,19 @@
 	}
 
 	/* Ok, this is a data packet. Lookup the session. */
-	session = l2tp_session_find(net, NULL, session_id);
-	if (session == NULL)
+	session = l2tp_session_get(net, NULL, session_id, true);
+	if (!session)
 		goto discard;
 
 	tunnel = session->tunnel;
-	if (tunnel == NULL)
-		goto discard;
+	if (!tunnel)
+		goto discard_sess;
 
 	/* Trace packet contents, if enabled */
 	if (tunnel->debug & L2TP_MSG_DATA) {
 		length = min(32u, skb->len);
 		if (!pskb_may_pull(skb, length))
-			goto discard;
+			goto discard_sess;
 
 		/* Point to L2TP header */
 		optr = ptr = skb->data;
@@ -164,6 +165,7 @@
 	}
 
 	l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
+	l2tp_session_dec_refcount(session);
 
 	return 0;
 
@@ -176,21 +178,16 @@
 		goto discard;
 
 	tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
-	tunnel = l2tp_tunnel_find(net, tunnel_id);
-	if (tunnel != NULL)
-		sk = tunnel->sock;
-	else {
-		struct iphdr *iph = (struct iphdr *) skb_network_header(skb);
+	iph = (struct iphdr *)skb_network_header(skb);
 
-		read_lock_bh(&l2tp_ip_lock);
-		sk = __l2tp_ip_bind_lookup(net, iph->daddr, 0, tunnel_id);
+	read_lock_bh(&l2tp_ip_lock);
+	sk = __l2tp_ip_bind_lookup(net, iph->daddr, 0, tunnel_id);
+	if (!sk) {
 		read_unlock_bh(&l2tp_ip_lock);
-	}
-
-	if (sk == NULL)
 		goto discard;
-
+	}
 	sock_hold(sk);
+	read_unlock_bh(&l2tp_ip_lock);
 
 	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 		goto discard_put;
@@ -199,6 +196,12 @@
 
 	return sk_receive_skb(sk, skb, 1);
 
+discard_sess:
+	if (session->deref)
+		session->deref(session);
+	l2tp_session_dec_refcount(session);
+	goto discard;
+
 discard_put:
 	sock_put(sk);