net: reorder dev_addr_sem lock

Lockdep complains about circular lock in 1 -> 2 -> 3 (see below).

Change the lock ordering to be:
- rtnl_lock
- dev_addr_sem
- netdev_ops (only for lower devices!)
- team_lock (or other per-upper device lock)

1. rtnl_lock -> netdev_ops -> dev_addr_sem

rtnl_setlink
  rtnl_lock
    do_setlink IFLA_ADDRESS on lower
      netdev_ops
        dev_addr_sem

2. rtnl_lock -> team_lock -> netdev_ops

rtnl_newlink
  rtnl_lock
    do_setlink IFLA_MASTER on lower
      do_set_master
        team_add_slave
          team_lock
            team_port_add
	      dev_set_mtu
	        netdev_ops

3. rtnl_lock -> dev_addr_sem -> team_lock

rtnl_newlink
  rtnl_lock
    do_setlink IFLA_ADDRESS on upper
      dev_addr_sem
        netif_set_mac_address
          team_set_mac_address
            team_lock

4. rtnl_lock -> netdev_ops -> dev_addr_sem

rtnl_lock
  dev_ifsioc
    dev_set_mac_address_user

__tun_chr_ioctl
  rtnl_lock
    dev_set_mac_address_user

tap_ioctl
  rtnl_lock
    dev_set_mac_address_user

dev_set_mac_address_user
  netdev_lock_ops
    netif_set_mac_address_user
      dev_addr_sem

v2:
- move lock reorder to happen after kmalloc (Kuniyuki)

Cc: Kohei Enju <enjuk@amazon.com>
Fixes: df43d8bf1031 ("net: replace dev_addr_sem with netdev instance lock")
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250312190513.1252045-3-sdf@fomichev.me
Tested-by: Lei Yang <leiyang@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 9355058bf996..5a24a30dfc2d 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3088,13 +3088,24 @@ static int do_setlink(const struct sk_buff *skb, struct net_device *dev,
 			goto errout;
 		}
 		sa->sa_family = dev->type;
+
+		netdev_unlock_ops(dev);
+
+		/* dev_addr_sem is an outer lock, enforce proper ordering */
+		down_write(&dev_addr_sem);
+		netdev_lock_ops(dev);
+
 		memcpy(sa->sa_data, nla_data(tb[IFLA_ADDRESS]),
 		       dev->addr_len);
-		err = netif_set_mac_address_user(dev, sa, extack);
+		err = netif_set_mac_address(dev, sa, extack);
 		kfree(sa);
-		if (err)
+		if (err) {
+			up_write(&dev_addr_sem);
 			goto errout;
+		}
 		status |= DO_SETLINK_MODIFIED;
+
+		up_write(&dev_addr_sem);
 	}
 
 	if (tb[IFLA_MTU]) {