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net: reorder dev_addr_sem lock

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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: df43d8bf10 ("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>
This commit is contained in:
Stanislav Fomichev
2025-03-12 12:05:13 -07:00
committed by Paolo Abeni
parent 8033d2aef5
commit 6dd132516f
4 changed files with 16 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/netdevice.h
View File

@@ -4196,8 +4196,6 @@ int netif_set_mac_address(struct net_device *dev, struct sockaddr *sa,
struct netlink_ext_ack *extack);
int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa,
struct netlink_ext_ack *extack);
int netif_set_mac_address_user(struct net_device *dev, struct sockaddr *sa,
struct netlink_ext_ack *extack);
int dev_set_mac_address_user(struct net_device *dev, struct sockaddr *sa,
struct netlink_ext_ack *extack);
int dev_get_mac_address(struct sockaddr *sa, struct net *net, char *dev_name);

11
net/core/dev.c
View File

@@ -9577,17 +9577,6 @@ int netif_set_mac_address(struct net_device *dev, struct sockaddr *sa,
DECLARE_RWSEM(dev_addr_sem);
int netif_set_mac_address_user(struct net_device *dev, struct sockaddr *sa,
struct netlink_ext_ack *extack)
{
int ret;
down_write(&dev_addr_sem);
ret = netif_set_mac_address(dev, sa, extack);
up_write(&dev_addr_sem);
return ret;
}
int dev_get_mac_address(struct sockaddr *sa, struct net *net, char *dev_name)
{
size_t size = sizeof(sa->sa_data_min);

4
net/core/dev_api.c
View File

@@ -89,9 +89,11 @@ int dev_set_mac_address_user(struct net_device *dev, struct sockaddr *sa,
{
int ret;
down_write(&dev_addr_sem);
netdev_lock_ops(dev);
ret = netif_set_mac_address_user(dev, sa, extack);
ret = netif_set_mac_address(dev, sa, extack);
netdev_unlock_ops(dev);
up_write(&dev_addr_sem);
return ret;
}

15
net/core/rtnetlink.c
View File

@@ -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]) {