tipc: fix deadlock during socket release

A deadlock might occur if name table is withdrawn in socket release
routine, and while packets are still being received from bearer.

       CPU0                       CPU1
T0:   recv_msg()               release()
T1:   tipc_recv_msg()          tipc_withdraw()
T2:   [grab node lock]         [grab port lock]
T3:   tipc_link_wakeup_ports() tipc_nametbl_withdraw()
T4:   [grab port lock]*        named_cluster_distribute()
T5:   wakeupdispatch()         tipc_link_send()
T6:                            [grab node lock]*

The opposite order of holding port lock and node lock on above two
different paths may result in a deadlock. If socket lock instead of
port lock is used to protect port instance in tipc_withdraw(), the
reverse order of holding port lock and node lock will be eliminated,
as a result, the deadlock is killed as well.

Reported-by: Lars Everbrand <lars.everbrand@ericsson.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 31 insertions, 15 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 3b61851bb927..e741416d1d24 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -354,7 +354,7 @@ static int release(struct socket *sock)
 	 * Delete TIPC port; this ensures no more messages are queued
 	 * (also disconnects an active connection & sends a 'FIN-' to peer)
 	 */
-	res = tipc_deleteport(tport->ref);
+	res = tipc_deleteport(tport);
 
 	/* Discard any remaining (connection-based) messages in receive queue */
 	__skb_queue_purge(&sk->sk_receive_queue);
@@ -386,30 +386,46 @@ static int release(struct socket *sock)
  */
 static int bind(struct socket *sock, struct sockaddr *uaddr, int uaddr_len)
 {
+	struct sock *sk = sock->sk;
 	struct sockaddr_tipc *addr = (struct sockaddr_tipc *)uaddr;
-	u32 portref = tipc_sk_port(sock->sk)->ref;
+	struct tipc_port *tport = tipc_sk_port(sock->sk);
+	int res = -EINVAL;
 
-	if (unlikely(!uaddr_len))
-		return tipc_withdraw(portref, 0, NULL);
+	lock_sock(sk);
+	if (unlikely(!uaddr_len)) {
+		res = tipc_withdraw(tport, 0, NULL);
+		goto exit;
+	}
 
-	if (uaddr_len < sizeof(struct sockaddr_tipc))
-		return -EINVAL;
-	if (addr->family != AF_TIPC)
-		return -EAFNOSUPPORT;
+	if (uaddr_len < sizeof(struct sockaddr_tipc)) {
+		res = -EINVAL;
+		goto exit;
+	}
+	if (addr->family != AF_TIPC) {
+		res = -EAFNOSUPPORT;
+		goto exit;
+	}
 
 	if (addr->addrtype == TIPC_ADDR_NAME)
 		addr->addr.nameseq.upper = addr->addr.nameseq.lower;
-	else if (addr->addrtype != TIPC_ADDR_NAMESEQ)
-		return -EAFNOSUPPORT;
+	else if (addr->addrtype != TIPC_ADDR_NAMESEQ) {
+		res = -EAFNOSUPPORT;
+		goto exit;
+	}
 
 	if ((addr->addr.nameseq.type < TIPC_RESERVED_TYPES) &&
 	    (addr->addr.nameseq.type != TIPC_TOP_SRV) &&
-	    (addr->addr.nameseq.type != TIPC_CFG_SRV))
-		return -EACCES;
+	    (addr->addr.nameseq.type != TIPC_CFG_SRV)) {
+		res = -EACCES;
+		goto exit;
+	}
 
-	return (addr->scope > 0) ?
-		tipc_publish(portref, addr->scope, &addr->addr.nameseq) :
-		tipc_withdraw(portref, -addr->scope, &addr->addr.nameseq);
+	res = (addr->scope > 0) ?
+		tipc_publish(tport, addr->scope, &addr->addr.nameseq) :
+		tipc_withdraw(tport, -addr->scope, &addr->addr.nameseq);
+exit:
+	release_sock(sk);
+	return res;
 }
 
 /**