bonding: primary_slave & curr_active_slave are not cleaned on enslave failure

On enslave failure primary_slave can point to new_slave which is to be
freed, and the same applies to curr_active_slave. So check if this is
the case and clean up properly after err_detach because that's the first
error code path after they're set.
Signed-off-by: NNikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -1909,7 +1909,17 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 	bond_del_vlans_from_slave(bond, slave_dev);
 	write_lock_bh(&bond->lock);
 	bond_detach_slave(bond, new_slave);
+	if (bond->primary_slave == new_slave)
+		bond->primary_slave = NULL;
 	write_unlock_bh(&bond->lock);
+	if (bond->curr_active_slave == new_slave) {
+		read_lock(&bond->lock);
+		write_lock_bh(&bond->curr_slave_lock);
+		bond_change_active_slave(bond, NULL);
+		bond_select_active_slave(bond);
+		write_unlock_bh(&bond->curr_slave_lock);
+		read_unlock(&bond->lock);
+	}
 
 err_close:
 	slave_dev->priv_flags &= ~IFF_BONDING;