1 files changed, 30 insertions, 26 deletions

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 3d8ca1231f8f..b56cb1df4fc0 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -428,16 +428,6 @@ static void pppol2tp_put_sk(struct rcu_head *head)
  */
 static void pppol2tp_session_close(struct l2tp_session *session)
 {
-	struct pppol2tp_session *ps;
-
-	ps = l2tp_session_priv(session);
-	mutex_lock(&ps->sk_lock);
-	ps->__sk = rcu_dereference_protected(ps->sk,
-					     lockdep_is_held(&ps->sk_lock));
-	RCU_INIT_POINTER(ps->sk, NULL);
-	if (ps->__sk)
-		call_rcu(&ps->rcu, pppol2tp_put_sk);
-	mutex_unlock(&ps->sk_lock);
 }
 
 /* Really kill the session socket. (Called from sock_put() if
@@ -480,15 +470,24 @@ static int pppol2tp_release(struct socket *sock)
 	sock_orphan(sk);
 	sock->sk = NULL;
 
-	/* If the socket is associated with a session,
-	 * l2tp_session_delete will call pppol2tp_session_close which
-	 * will drop the session's ref on the socket.
-	 */
 	session = pppol2tp_sock_to_session(sk);
 	if (session) {
+		struct pppol2tp_session *ps;
+
 		l2tp_session_delete(session);
-		/* drop the ref obtained by pppol2tp_sock_to_session */
-		sock_put(sk);
+
+		ps = l2tp_session_priv(session);
+		mutex_lock(&ps->sk_lock);
+		ps->__sk = rcu_dereference_protected(ps->sk,
+						     lockdep_is_held(&ps->sk_lock));
+		RCU_INIT_POINTER(ps->sk, NULL);
+		mutex_unlock(&ps->sk_lock);
+		call_rcu(&ps->rcu, pppol2tp_put_sk);
+
+		/* Rely on the sock_put() call at the end of the function for
+		 * dropping the reference held by pppol2tp_sock_to_session().
+		 * The last reference will be dropped by pppol2tp_put_sk().
+		 */
 	}
 
 	release_sock(sk);
@@ -742,7 +741,8 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 		 */
 		mutex_lock(&ps->sk_lock);
 		if (rcu_dereference_protected(ps->sk,
-					      lockdep_is_held(&ps->sk_lock))) {
+					      lockdep_is_held(&ps->sk_lock)) ||
+		    ps->__sk) {
 			mutex_unlock(&ps->sk_lock);
 			error = -EEXIST;
 			goto end;
@@ -803,7 +803,6 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 
 out_no_ppp:
 	/* This is how we get the session context from the socket. */
-	sock_hold(sk);
 	sk->sk_user_data = session;
 	rcu_assign_pointer(ps->sk, sk);
 	mutex_unlock(&ps->sk_lock);
@@ -1576,6 +1575,10 @@ static void pppol2tp_next_tunnel(struct net *net, struct pppol2tp_seq_data *pd)
 
 static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd)
 {
+	/* Drop reference taken during previous invocation */
+	if (pd->session)
+		l2tp_session_dec_refcount(pd->session);
+
 	pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx);
 	pd->session_idx++;
 
@@ -1624,11 +1627,16 @@ static void pppol2tp_seq_stop(struct seq_file *p, void *v)
 	if (!pd || pd == SEQ_START_TOKEN)
 		return;
 
-	/* Drop reference taken by last invocation of pppol2tp_next_tunnel() */
+	/* Drop reference taken by last invocation of pppol2tp_next_session()
+	 * or pppol2tp_next_tunnel().
+	 */
+	if (pd->session) {
+		l2tp_session_dec_refcount(pd->session);
+		pd->session = NULL;
+	}
 	if (pd->tunnel) {
 		l2tp_tunnel_dec_refcount(pd->tunnel);
 		pd->tunnel = NULL;
-		pd->session = NULL;
 	}
 }
 
@@ -1723,14 +1731,10 @@ static int pppol2tp_seq_show(struct seq_file *m, void *v)
 		goto out;
 	}
 
-	/* Show the tunnel or session context.
-	 */
-	if (!pd->session) {
+	if (!pd->session)
 		pppol2tp_seq_tunnel_show(m, pd->tunnel);
-	} else {
+	else
 		pppol2tp_seq_session_show(m, pd->session);
-		l2tp_session_dec_refcount(pd->session);
-	}
 
 out:
 	return 0;