net: change addr_list_lock back to static key

The dynamic key update for addr_list_lock still causes troubles,
for example the following race condition still exists:

CPU 0:				CPU 1:
(RCU read lock)			(RTNL lock)
dev_mc_seq_show()		netdev_update_lockdep_key()
				  -> lockdep_unregister_key()
 -> netif_addr_lock_bh()

because lockdep doesn't provide an API to update it atomically.
Therefore, we have to move it back to static keys and use subclass
for nest locking like before.

In commit 1a33e10e4a95 ("net: partially revert dynamic lockdep key
changes"), I already reverted most parts of commit ab92d68fc22f
("net: core: add generic lockdep keys").

This patch reverts the rest and also part of commit f3b0a18bb6cb
("net: remove unnecessary variables and callback"). After this
patch, addr_list_lock changes back to using static keys and
subclasses to satisfy lockdep. Thanks to dev->lower_level, we do
not have to change back to ->ndo_get_lock_subclass().

And hopefully this reduces some syzbot lockdep noises too.

Reported-by: syzbot+f3a0e80c34b3fc28ac5e@syzkaller.appspotmail.com
Cc: Taehee Yoo <ap420073@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

9 files changed, 46 insertions, 23 deletions

diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index f00bb57f0f60..c8d6a07e23c5 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -494,6 +494,7 @@ static void vlan_dev_set_rx_mode(struct net_device *vlan_dev)
  * separate class since they always nest.
  */
 static struct lock_class_key vlan_netdev_xmit_lock_key;
+static struct lock_class_key vlan_netdev_addr_lock_key;
 
 static void vlan_dev_set_lockdep_one(struct net_device *dev,
 				     struct netdev_queue *txq,
@@ -502,8 +503,11 @@ static void vlan_dev_set_lockdep_one(struct net_device *dev,
 	lockdep_set_class(&txq->_xmit_lock, &vlan_netdev_xmit_lock_key);
 }
 
-static void vlan_dev_set_lockdep_class(struct net_device *dev)
+static void vlan_dev_set_lockdep_class(struct net_device *dev, int subclass)
 {
+	lockdep_set_class_and_subclass(&dev->addr_list_lock,
+				       &vlan_netdev_addr_lock_key,
+				       subclass);
 	netdev_for_each_tx_queue(dev, vlan_dev_set_lockdep_one, NULL);
 }
 
@@ -597,7 +601,7 @@ static int vlan_dev_init(struct net_device *dev)
 
 	SET_NETDEV_DEVTYPE(dev, &vlan_type);
 
-	vlan_dev_set_lockdep_class(dev);
+	vlan_dev_set_lockdep_class(dev, dev->lower_level);
 
 	vlan->vlan_pcpu_stats = netdev_alloc_pcpu_stats(struct vlan_pcpu_stats);
 	if (!vlan->vlan_pcpu_stats)
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 0ddd80130ea3..f1f1c86f3419 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -745,6 +745,7 @@ static int batadv_interface_kill_vid(struct net_device *dev, __be16 proto,
  * separate class since they always nest.
  */
 static struct lock_class_key batadv_netdev_xmit_lock_key;
+static struct lock_class_key batadv_netdev_addr_lock_key;
 
 /**
  * batadv_set_lockdep_class_one() - Set lockdep class for a single tx queue
@@ -765,6 +766,7 @@ static void batadv_set_lockdep_class_one(struct net_device *dev,
  */
 static void batadv_set_lockdep_class(struct net_device *dev)
 {
+	lockdep_set_class(&dev->addr_list_lock, &batadv_netdev_addr_lock_key);
 	netdev_for_each_tx_queue(dev, batadv_set_lockdep_class_one, NULL);
 }
 
diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 8ec1362588af..8c7b78f8bc23 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -105,6 +105,13 @@ out:
 	return NETDEV_TX_OK;
 }
 
+static struct lock_class_key bridge_netdev_addr_lock_key;
+
+static void br_set_lockdep_class(struct net_device *dev)
+{
+	lockdep_set_class(&dev->addr_list_lock, &bridge_netdev_addr_lock_key);
+}
+
 static int br_dev_init(struct net_device *dev)
 {
 	struct net_bridge *br = netdev_priv(dev);
@@ -143,6 +150,7 @@ static int br_dev_init(struct net_device *dev)
 		br_fdb_hash_fini(br);
 	}
 
+	br_set_lockdep_class(dev);
 	return err;
 }
 
diff --git a/net/core/dev.c b/net/core/dev.c
index 061496a1f640..6bc2388141f6 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -439,6 +439,7 @@ static const char *const netdev_lock_name[] = {
 	"_xmit_IEEE802154", "_xmit_VOID", "_xmit_NONE"};
 
 static struct lock_class_key netdev_xmit_lock_key[ARRAY_SIZE(netdev_lock_type)];
+static struct lock_class_key netdev_addr_lock_key[ARRAY_SIZE(netdev_lock_type)];
 
 static inline unsigned short netdev_lock_pos(unsigned short dev_type)
 {
@@ -460,11 +461,25 @@ static inline void netdev_set_xmit_lockdep_class(spinlock_t *lock,
 	lockdep_set_class_and_name(lock, &netdev_xmit_lock_key[i],
 				   netdev_lock_name[i]);
 }
+
+static inline void netdev_set_addr_lockdep_class(struct net_device *dev)
+{
+	int i;
+
+	i = netdev_lock_pos(dev->type);
+	lockdep_set_class_and_name(&dev->addr_list_lock,
+				   &netdev_addr_lock_key[i],
+				   netdev_lock_name[i]);
+}
 #else
 static inline void netdev_set_xmit_lockdep_class(spinlock_t *lock,
 						 unsigned short dev_type)
 {
 }
+
+static inline void netdev_set_addr_lockdep_class(struct net_device *dev)
+{
+}
 #endif
 
 /*******************************************************************************
@@ -9373,15 +9388,6 @@ void netif_tx_stop_all_queues(struct net_device *dev)
 }
 EXPORT_SYMBOL(netif_tx_stop_all_queues);
 
-void netdev_update_lockdep_key(struct net_device *dev)
-{
-	lockdep_unregister_key(&dev->addr_list_lock_key);
-	lockdep_register_key(&dev->addr_list_lock_key);
-
-	lockdep_set_class(&dev->addr_list_lock, &dev->addr_list_lock_key);
-}
-EXPORT_SYMBOL(netdev_update_lockdep_key);
-
 /**
  *	register_netdevice	- register a network device
  *	@dev: device to register
@@ -9420,7 +9426,7 @@ int register_netdevice(struct net_device *dev)
 		return ret;
 
 	spin_lock_init(&dev->addr_list_lock);
-	lockdep_set_class(&dev->addr_list_lock, &dev->addr_list_lock_key);
+	netdev_set_addr_lockdep_class(dev);
 
 	ret = dev_get_valid_name(net, dev, dev->name);
 	if (ret < 0)
@@ -9939,8 +9945,6 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 
 	dev_net_set(dev, &init_net);
 
-	lockdep_register_key(&dev->addr_list_lock_key);
-
 	dev->gso_max_size = GSO_MAX_SIZE;
 	dev->gso_max_segs = GSO_MAX_SEGS;
 	dev->upper_level = 1;
@@ -10028,8 +10032,6 @@ void free_netdev(struct net_device *dev)
 	free_percpu(dev->xdp_bulkq);
 	dev->xdp_bulkq = NULL;
 
-	lockdep_unregister_key(&dev->addr_list_lock_key);
-
 	/*  Compatibility with error handling in drivers */
 	if (dev->reg_state == NETREG_UNINITIALIZED) {
 		netdev_freemem(dev);
diff --git a/net/core/dev_addr_lists.c b/net/core/dev_addr_lists.c
index 2f949b5a1eb9..6393ba930097 100644
--- a/net/core/dev_addr_lists.c
+++ b/net/core/dev_addr_lists.c
@@ -637,7 +637,7 @@ int dev_uc_sync(struct net_device *to, struct net_device *from)
 	if (to->addr_len != from->addr_len)
 		return -EINVAL;
 
-	netif_addr_lock(to);
+	netif_addr_lock_nested(to);
 	err = __hw_addr_sync(&to->uc, &from->uc, to->addr_len);
 	if (!err)
 		__dev_set_rx_mode(to);
@@ -667,7 +667,7 @@ int dev_uc_sync_multiple(struct net_device *to, struct net_device *from)
 	if (to->addr_len != from->addr_len)
 		return -EINVAL;
 
-	netif_addr_lock(to);
+	netif_addr_lock_nested(to);
 	err = __hw_addr_sync_multiple(&to->uc, &from->uc, to->addr_len);
 	if (!err)
 		__dev_set_rx_mode(to);
@@ -691,7 +691,7 @@ void dev_uc_unsync(struct net_device *to, struct net_device *from)
 		return;
 
 	netif_addr_lock_bh(from);
-	netif_addr_lock(to);
+	netif_addr_lock_nested(to);
 	__hw_addr_unsync(&to->uc, &from->uc, to->addr_len);
 	__dev_set_rx_mode(to);
 	netif_addr_unlock(to);
@@ -858,7 +858,7 @@ int dev_mc_sync(struct net_device *to, struct net_device *from)
 	if (to->addr_len != from->addr_len)
 		return -EINVAL;
 
-	netif_addr_lock(to);
+	netif_addr_lock_nested(to);
 	err = __hw_addr_sync(&to->mc, &from->mc, to->addr_len);
 	if (!err)
 		__dev_set_rx_mode(to);
@@ -888,7 +888,7 @@ int dev_mc_sync_multiple(struct net_device *to, struct net_device *from)
 	if (to->addr_len != from->addr_len)
 		return -EINVAL;
 
-	netif_addr_lock(to);
+	netif_addr_lock_nested(to);
 	err = __hw_addr_sync_multiple(&to->mc, &from->mc, to->addr_len);
 	if (!err)
 		__dev_set_rx_mode(to);
@@ -912,7 +912,7 @@ void dev_mc_unsync(struct net_device *to, struct net_device *from)
 		return;
 
 	netif_addr_lock_bh(from);
-	netif_addr_lock(to);
+	netif_addr_lock_nested(to);
 	__hw_addr_unsync(&to->mc, &from->mc, to->addr_len);
 	__dev_set_rx_mode(to);
 	netif_addr_unlock(to);
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 2269199c5891..9aedc15736ad 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2462,7 +2462,6 @@ static int do_set_master(struct net_device *dev, int ifindex,
 			err = ops->ndo_del_slave(upper_dev, dev);
 			if (err)
 				return err;
-			netdev_update_lockdep_key(dev);
 		} else {
 			return -EOPNOTSUPP;
 		}
diff --git a/net/dsa/master.c b/net/dsa/master.c
index a621367c6e8c..480a61460c23 100644
--- a/net/dsa/master.c
+++ b/net/dsa/master.c
@@ -327,6 +327,8 @@ static void dsa_master_reset_mtu(struct net_device *dev)
 	rtnl_unlock();
 }
 
+static struct lock_class_key dsa_master_addr_list_lock_key;
+
 int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp)
 {
 	int ret;
@@ -345,6 +347,8 @@ int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp)
 	wmb();
 
 	dev->dsa_ptr = cpu_dp;
+	lockdep_set_class(&dev->addr_list_lock,
+			  &dsa_master_addr_list_lock_key);
 	ret = dsa_master_ethtool_setup(dev);
 	if (ret)
 		return ret;
diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c
index eccc7d366e17..f90ef6934b8f 100644
--- a/net/netrom/af_netrom.c
+++ b/net/netrom/af_netrom.c
@@ -70,6 +70,7 @@ static const struct proto_ops nr_proto_ops;
  * separate class since they always nest.
  */
 static struct lock_class_key nr_netdev_xmit_lock_key;
+static struct lock_class_key nr_netdev_addr_lock_key;
 
 static void nr_set_lockdep_one(struct net_device *dev,
 			       struct netdev_queue *txq,
@@ -80,6 +81,7 @@ static void nr_set_lockdep_one(struct net_device *dev,
 
 static void nr_set_lockdep_key(struct net_device *dev)
 {
+	lockdep_set_class(&dev->addr_list_lock, &nr_netdev_addr_lock_key);
 	netdev_for_each_tx_queue(dev, nr_set_lockdep_one, NULL);
 }
 
diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
index e7a872207b46..ce85656ac9c1 100644
--- a/net/rose/af_rose.c
+++ b/net/rose/af_rose.c
@@ -71,6 +71,7 @@ ax25_address rose_callsign;
  * separate class since they always nest.
  */
 static struct lock_class_key rose_netdev_xmit_lock_key;
+static struct lock_class_key rose_netdev_addr_lock_key;
 
 static void rose_set_lockdep_one(struct net_device *dev,
 				 struct netdev_queue *txq,
@@ -81,6 +82,7 @@ static void rose_set_lockdep_one(struct net_device *dev,
 
 static void rose_set_lockdep_key(struct net_device *dev)
 {
+	lockdep_set_class(&dev->addr_list_lock, &rose_netdev_addr_lock_key);
 	netdev_for_each_tx_queue(dev, rose_set_lockdep_one, NULL);
 }