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>

7 files changed, 22 insertions, 9 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index a25c65d4af71..004919aea5fb 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3687,8 +3687,6 @@ static int bond_do_ioctl(struct net_device *bond_dev, struct ifreq *ifr, int cmd
 	case BOND_RELEASE_OLD:
 	case SIOCBONDRELEASE:
 		res = bond_release(bond_dev, slave_dev);
-		if (!res)
-			netdev_update_lockdep_key(slave_dev);
 		break;
 	case BOND_SETHWADDR_OLD:
 	case SIOCBONDSETHWADDR:
diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
index 215c10923289..ddb3916d3506 100644
--- a/drivers/net/bonding/bond_options.c
+++ b/drivers/net/bonding/bond_options.c
@@ -1398,8 +1398,6 @@ static int bond_option_slaves_set(struct bonding *bond,
 	case '-':
 		slave_dbg(bond->dev, dev, "Releasing interface\n");
 		ret = bond_release(bond->dev, dev);
-		if (!ret)
-			netdev_update_lockdep_key(dev);
 		break;
 
 	default:
diff --git a/drivers/net/hamradio/bpqether.c b/drivers/net/hamradio/bpqether.c
index 60dcaf2a04a9..1ad6085994b1 100644
--- a/drivers/net/hamradio/bpqether.c
+++ b/drivers/net/hamradio/bpqether.c
@@ -113,6 +113,7 @@ static LIST_HEAD(bpq_devices);
  * off into a separate class since they always nest.
  */
 static struct lock_class_key bpq_netdev_xmit_lock_key;
+static struct lock_class_key bpq_netdev_addr_lock_key;
 
 static void bpq_set_lockdep_class_one(struct net_device *dev,
 				      struct netdev_queue *txq,
@@ -123,6 +124,7 @@ static void bpq_set_lockdep_class_one(struct net_device *dev,
 
 static void bpq_set_lockdep_class(struct net_device *dev)
 {
+	lockdep_set_class(&dev->addr_list_lock, &bpq_netdev_addr_lock_key);
 	netdev_for_each_tx_queue(dev, bpq_set_lockdep_class_one, NULL);
 }
 
diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index 20b53e255f68..e56547bfdac9 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -3999,6 +3999,8 @@ static int macsec_add_dev(struct net_device *dev, sci_t sci, u8 icv_len)
 	return 0;
 }
 
+static struct lock_class_key macsec_netdev_addr_lock_key;
+
 static int macsec_newlink(struct net *net, struct net_device *dev,
 			  struct nlattr *tb[], struct nlattr *data[],
 			  struct netlink_ext_ack *extack)
@@ -4050,6 +4052,9 @@ static int macsec_newlink(struct net *net, struct net_device *dev,
 		return err;
 
 	netdev_lockdep_set_classes(dev);
+	lockdep_set_class_and_subclass(&dev->addr_list_lock,
+				       &macsec_netdev_addr_lock_key,
+				       dev->lower_level);
 
 	err = netdev_upper_dev_link(real_dev, dev, extack);
 	if (err < 0)
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 563aed5b3d9f..6a6cc9f75307 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -860,6 +860,8 @@ static int macvlan_do_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
  * "super class" of normal network devices; split their locks off into a
  * separate class since they always nest.
  */
+static struct lock_class_key macvlan_netdev_addr_lock_key;
+
 #define ALWAYS_ON_OFFLOADS \
 	(NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE | \
 	 NETIF_F_GSO_ROBUST | NETIF_F_GSO_ENCAP_ALL)
@@ -875,6 +877,14 @@ static int macvlan_do_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 #define MACVLAN_STATE_MASK \
 	((1<<__LINK_STATE_NOCARRIER) | (1<<__LINK_STATE_DORMANT))
 
+static void macvlan_set_lockdep_class(struct net_device *dev)
+{
+	netdev_lockdep_set_classes(dev);
+	lockdep_set_class_and_subclass(&dev->addr_list_lock,
+				       &macvlan_netdev_addr_lock_key,
+				       dev->lower_level);
+}
+
 static int macvlan_init(struct net_device *dev)
 {
 	struct macvlan_dev *vlan = netdev_priv(dev);
@@ -892,8 +902,7 @@ static int macvlan_init(struct net_device *dev)
 	dev->gso_max_size	= lowerdev->gso_max_size;
 	dev->gso_max_segs	= lowerdev->gso_max_segs;
 	dev->hard_header_len	= lowerdev->hard_header_len;
-
-	netdev_lockdep_set_classes(dev);
+	macvlan_set_lockdep_class(dev);
 
 	vlan->pcpu_stats = netdev_alloc_pcpu_stats(struct vlan_pcpu_stats);
 	if (!vlan->pcpu_stats)
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 5bb448ae6c9c..47424b2da643 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -4245,10 +4245,8 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[],
 		mod_timer(&vxlan->age_timer, jiffies);
 
 	netdev_adjacent_change_commit(dst->remote_dev, lowerdev, dev);
-	if (lowerdev && lowerdev != dst->remote_dev) {
+	if (lowerdev && lowerdev != dst->remote_dev)
 		dst->remote_dev = lowerdev;
-		netdev_update_lockdep_key(lowerdev);
-	}
 	vxlan_config_apply(dev, &conf, lowerdev, vxlan->net, true);
 	return 0;
 }
diff --git a/drivers/net/wireless/intersil/hostap/hostap_hw.c b/drivers/net/wireless/intersil/hostap/hostap_hw.c
index aadf3dec5bf3..2ab34cf74ecc 100644
--- a/drivers/net/wireless/intersil/hostap/hostap_hw.c
+++ b/drivers/net/wireless/intersil/hostap/hostap_hw.c
@@ -3048,6 +3048,7 @@ static void prism2_clear_set_tim_queue(local_info_t *local)
  * This is a natural nesting, which needs a split lock type.
  */
 static struct lock_class_key hostap_netdev_xmit_lock_key;
+static struct lock_class_key hostap_netdev_addr_lock_key;
 
 static void prism2_set_lockdep_class_one(struct net_device *dev,
 					 struct netdev_queue *txq,
@@ -3059,6 +3060,8 @@ static void prism2_set_lockdep_class_one(struct net_device *dev,
 
 static void prism2_set_lockdep_class(struct net_device *dev)
 {
+	lockdep_set_class(&dev->addr_list_lock,
+			  &hostap_netdev_addr_lock_key);
 	netdev_for_each_tx_queue(dev, prism2_set_lockdep_class_one, NULL);
 }