team: replace team lock with rtnl lock

syszbot reports various ordering issues for lower instance locks and
team lock. Switch to using rtnl lock for protecting team device,
similar to bonding. Based on the patch by Tetsuo Handa.

Cc: Jiri Pirko <[e-mail]>
Cc: Tetsuo Handa <[e-mail]>
Reported-by: [e-mail]
Closes: https://syzkaller.appspot.com/bug?extid=705c61d60b091ef42c04
Reported-by: [e-mail]
Closes: https://syzkaller.appspot.com/bug?extid=71fd22ae4b81631e22fd
Fixes: 6b1d3c5f675c ("team: grab team lock during team_change_rx_flags")
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Stanislav Fomichev <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/team/team_core.c

···
  * Enable/disable port by adding to enabled port hashlist and setting
  * port->index (Might be racy so reader could see incorrect ifindex when
  * processing a flying packet, but that is not a problem). Write guarded
- * by team->lock.
+ * by RTNL.
  */
 static void team_port_enable(struct team *team,
 			     struct team_port *port)
···
 		goto err_options_register;
 	netif_carrier_off(dev);
 
-	lockdep_register_key(&team->team_lock_key);
-	__mutex_init(&team->lock, "team->team_lock_key", &team->team_lock_key);
 	netdev_lockdep_set_classes(dev);
 
 	return 0;
···
 	struct team_port *port;
 	struct team_port *tmp;
 
-	mutex_lock(&team->lock);
+	ASSERT_RTNL();
+
 	list_for_each_entry_safe(port, tmp, &team->port_list, list)
 		team_port_del(team, port->dev);
 
···
 	team_mcast_rejoin_fini(team);
 	team_notify_peers_fini(team);
 	team_queue_override_fini(team);
-	mutex_unlock(&team->lock);
 	netdev_change_features(dev);
-	lockdep_unregister_key(&team->team_lock_key);
 }
 
 static void team_destructor(struct net_device *dev)
···
 	struct team_port *port;
 	int inc;
 
-	mutex_lock(&team->lock);
+	ASSERT_RTNL();
+
 	list_for_each_entry(port, &team->port_list, list) {
 		if (change & IFF_PROMISC) {
 			inc = dev->flags & IFF_PROMISC ? 1 : -1;
···
 			dev_set_allmulti(port->dev, inc);
 		}
 	}
-	mutex_unlock(&team->lock);
 }
 
 static void team_set_rx_mode(struct net_device *dev)
···
 	struct team *team = netdev_priv(dev);
 	struct team_port *port;
 
+	ASSERT_RTNL();
+
 	if (dev->type == ARPHRD_ETHER && !is_valid_ether_addr(addr->sa_data))
 		return -EADDRNOTAVAIL;
 	dev_addr_set(dev, addr->sa_data);
-	mutex_lock(&team->lock);
 	list_for_each_entry(port, &team->port_list, list)
 		if (team->ops.port_change_dev_addr)
 			team->ops.port_change_dev_addr(team, port);
-	mutex_unlock(&team->lock);
 	return 0;
 }
 
···
 	struct team_port *port;
 	int err;
 
-	/*
-	 * Alhough this is reader, it's guarded by team lock. It's not possible
-	 * to traverse list in reverse under rcu_read_lock
-	 */
-	mutex_lock(&team->lock);
+	ASSERT_RTNL();
+
 	team->port_mtu_change_allowed = true;
 	list_for_each_entry(port, &team->port_list, list) {
 		err = dev_set_mtu(port->dev, new_mtu);
···
 		}
 	}
 	team->port_mtu_change_allowed = false;
-	mutex_unlock(&team->lock);
 
 	WRITE_ONCE(dev->mtu, new_mtu);
 
···
 	list_for_each_entry_continue_reverse(port, &team->port_list, list)
 		dev_set_mtu(port->dev, dev->mtu);
 	team->port_mtu_change_allowed = false;
-	mutex_unlock(&team->lock);
 
 	return err;
 }
···
 	struct team_port *port;
 	int err;
 
-	/*
-	 * Alhough this is reader, it's guarded by team lock. It's not possible
-	 * to traverse list in reverse under rcu_read_lock
-	 */
-	mutex_lock(&team->lock);
+	ASSERT_RTNL();
+
 	list_for_each_entry(port, &team->port_list, list) {
 		err = vlan_vid_add(port->dev, proto, vid);
 		if (err)
 			goto unwind;
 	}
-	mutex_unlock(&team->lock);
 
 	return 0;
 
 unwind:
 	list_for_each_entry_continue_reverse(port, &team->port_list, list)
 		vlan_vid_del(port->dev, proto, vid);
-	mutex_unlock(&team->lock);
 
 	return err;
 }
···
 	struct team *team = netdev_priv(dev);
 	struct team_port *port;
 
-	mutex_lock(&team->lock);
+	ASSERT_RTNL();
+
 	list_for_each_entry(port, &team->port_list, list)
 		vlan_vid_del(port->dev, proto, vid);
-	mutex_unlock(&team->lock);
 
 	return 0;
 }
···
 {
 	struct team *team = netdev_priv(dev);
 
-	mutex_lock(&team->lock);
+	ASSERT_RTNL();
+
 	__team_netpoll_cleanup(team);
-	mutex_unlock(&team->lock);
 }
 
 static int team_netpoll_setup(struct net_device *dev)
···
 	struct team_port *port;
 	int err = 0;
 
-	mutex_lock(&team->lock);
+	ASSERT_RTNL();
+
 	list_for_each_entry(port, &team->port_list, list) {
 		err = __team_port_enable_netpoll(port);
 		if (err) {
···
 			break;
 		}
 	}
-	mutex_unlock(&team->lock);
 	return err;
 }
 #endif
···
 	struct team *team = netdev_priv(dev);
 	int err;
 
-	mutex_lock(&team->lock);
+	ASSERT_RTNL();
+
 	err = team_port_add(team, port_dev, extack);
-	mutex_unlock(&team->lock);
 
 	if (!err)
 		netdev_change_features(dev);
···
 	struct team *team = netdev_priv(dev);
 	int err;
 
-	mutex_lock(&team->lock);
+	ASSERT_RTNL();
+
 	err = team_port_del(team, port_dev);
-	mutex_unlock(&team->lock);
 
 	if (err)
 		return err;
 
-	if (netif_is_team_master(port_dev)) {
-		lockdep_unregister_key(&team->team_lock_key);
-		lockdep_register_key(&team->team_lock_key);
-		lockdep_set_class(&team->lock, &team->team_lock_key);
-	}
 	netdev_change_features(dev);
 
 	return err;
···
 static struct team *team_nl_team_get(struct genl_info *info)
 {
 	struct net *net = genl_info_net(info);
-	int ifindex;
 	struct net_device *dev;
-	struct team *team;
+	int ifindex;
+
+	ASSERT_RTNL();
 
 	if (!info->attrs[TEAM_ATTR_TEAM_IFINDEX])
 		return NULL;
···
 		return NULL;
 	}
 
-	team = netdev_priv(dev);
-	mutex_lock(&team->lock);
-	return team;
+	return netdev_priv(dev);
 }
 
 static void team_nl_team_put(struct team *team)
 {
-	mutex_unlock(&team->lock);
 	dev_put(team->dev);
 }
 
···
 	int err;
 	LIST_HEAD(sel_opt_inst_list);
 
+	rtnl_lock();
+
 	team = team_nl_team_get(info);
-	if (!team)
-		return -EINVAL;
+	if (!team) {
+		err = -EINVAL;
+		goto rtnl_unlock;
+	}
 
 	list_for_each_entry(opt_inst, &team->option_inst_list, list)
 		list_add_tail(&opt_inst->tmp_list, &sel_opt_inst_list);
···
 				       &sel_opt_inst_list);
 
 	team_nl_team_put(team);
+
+rtnl_unlock:
+	rtnl_unlock();
 
 	return err;
 }
···
 	struct team *team;
 	int err;
 
+	rtnl_lock();
+
 	team = team_nl_team_get(info);
-	if (!team)
-		return -EINVAL;
+	if (!team) {
+		err = -EINVAL;
+		goto rtnl_unlock;
+	}
 
 	err = team_nl_send_port_list_get(team, info->snd_portid, info->snd_seq,
 					 NLM_F_ACK, team_nl_send_unicast, NULL);
 
 	team_nl_team_put(team);
+
+rtnl_unlock:
+	rtnl_unlock();
 
 	return err;
 }
···
 
 static void team_port_change_check(struct team_port *port, bool linkup)
 {
-	struct team *team = port->team;
+	ASSERT_RTNL();
 
-	mutex_lock(&team->lock);
 	__team_port_change_check(port, linkup);
-	mutex_unlock(&team->lock);
 }
 
 

drivers/net/team/team_mode_activebackup.c

···
 {
 	struct team_port *active_port;
 
-	active_port = rcu_dereference_protected(ab_priv(team)->active_port,
-						lockdep_is_held(&team->lock));
+	active_port = rtnl_dereference(ab_priv(team)->active_port);
 	if (active_port)
 		ctx->data.u32_val = active_port->dev->ifindex;
 	else

drivers/net/team/team_mode_loadbalance.c

···
 	if (lb_priv->ex->orig_fprog) {
 		/* Clear old filter data */
 		__fprog_destroy(lb_priv->ex->orig_fprog);
-		orig_fp = rcu_dereference_protected(lb_priv->fp,
-						lockdep_is_held(&team->lock));
+		orig_fp = rtnl_dereference(lb_priv->fp);
 	}
 
 	rcu_assign_pointer(lb_priv->fp, fp);
···
 		return;
 
 	__fprog_destroy(lb_priv->ex->orig_fprog);
-	fp = rcu_dereference_protected(lb_priv->fp,
-				       lockdep_is_held(&team->lock));
+	fp = rtnl_dereference(lb_priv->fp);
 	bpf_prog_destroy(fp);
 }
 
···
 	lb_select_tx_port_func_t *func;
 	char *name;
 
-	func = rcu_dereference_protected(lb_priv->select_tx_port_func,
-					 lockdep_is_held(&team->lock));
+	func = rtnl_dereference(lb_priv->select_tx_port_func);
 	name = lb_select_tx_port_get_name(func);
 	BUG_ON(!name);
 	ctx->data.str_val = name;
···
 	team = lb_priv_ex->team;
 	lb_priv = get_lb_priv(team);
 
-	if (!mutex_trylock(&team->lock)) {
+	if (!rtnl_trylock()) {
 		schedule_delayed_work(&lb_priv_ex->stats.refresh_dw, 0);
 		return;
 	}
···
 	schedule_delayed_work(&lb_priv_ex->stats.refresh_dw,
 			      (lb_priv_ex->stats.refresh_interval * HZ) / 10);
 
-	mutex_unlock(&team->lock);
+	rtnl_unlock();
 }
 
 static void lb_stats_refresh_interval_get(struct team *team,

include/linux/if_team.h

···
 
 	const struct header_ops *header_ops_cache;
 
-	struct mutex lock; /* used for overall locking, e.g. port lists write */
-
 	/*
 	 * List of enabled ports and their count
 	 */
···
 		atomic_t count_pending;
 		struct delayed_work dw;
 	} mcast_rejoin;
-	struct lock_class_key team_lock_key;
 	long mode_priv[TEAM_MODE_PRIV_LONGS];
 };