Commit 6dd13251 authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Paolo Abeni
Browse files

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: df43d8bf ("net: replace dev_addr_sem with netdev instance lock")
Signed-off-by: default avatarStanislav Fomichev <sdf@fomichev.me>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250312190513.1252045-3-sdf@fomichev.me


Tested-by: default avatarLei Yang <leiyang@redhat.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 8033d2ae
Loading
Loading
Loading
Loading
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Please to comment