tipc: make function tipc_net_finalize() thread safe

The setting of the node address is not thread safe, meaning that
two discoverers may decide to set it simultanously, with a duplicate
entry in the name table as result. We fix that with this commit.

Fixes: 25b0b9c4 ("tipc: handle collisions of 32-bit node address hash values")
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/net.c

@@ -121,12 +121,17 @@ int tipc_net_init(struct net *net, u8 *node_id, u32 addr)
 
 void tipc_net_finalize(struct net *net, u32 addr)
 {
+	struct tipc_net *tn = tipc_net(net);
+
+	spin_lock_bh(&tn->node_list_lock);
+	if (!tipc_own_addr(net)) {
 		tipc_set_node_addr(net, addr);
-	smp_mb();
 		tipc_named_reinit(net);
 		tipc_sk_reinit(net);
 		tipc_nametbl_publish(net, TIPC_CFG_SRV, addr, addr,
 				     TIPC_CLUSTER_SCOPE, 0, addr);
+	}
+	spin_unlock_bh(&tn->node_list_lock);
 }
 
 void tipc_net_stop(struct net *net)