Re: [PATCH] net: net_failover: Fix the deadlock in slave register

[Simon Horman]

On Thu, Apr 23, 2026 at 07:59:43AM +0000, Faicker Mo wrote:
> There is netdev_lock_ops() before the NETDEV_REGISTER notifier
> in register_netdevice(), so use the non-locking functions
> in net_failover_slave_register().
> 
> Call Trace:
>  <TASK>
>  __schedule+0x30d/0x7a0
>  schedule+0x27/0x90
>  schedule_preempt_disabled+0x15/0x30
>  __mutex_lock.constprop.0+0x538/0x9e0
>  __mutex_lock_slowpath+0x13/0x20
>  mutex_lock+0x3b/0x50
>  dev_set_mtu+0x40/0xe0
>  net_failover_slave_register+0x24/0x280
>  failover_slave_register+0x103/0x1b0
>  failover_event+0x15e/0x210
>  ? dropmon_net_event+0xac/0xe0
>  notifier_call_chain+0x5e/0xe0
>  raw_notifier_call_chain+0x16/0x30
>  call_netdevice_notifiers_info+0x52/0xa0
>  register_netdevice+0x5f4/0x7c0
>  register_netdev+0x1e/0x40
>  _mlx5e_probe+0xe2/0x370 [mlx5_core]
>  mlx5e_probe+0x59/0x70 [mlx5_core]
>  ? __pfx_mlx5e_probe+0x10/0x10 [mlx5_core]
> 
> Fixes: 4c975fd70002 ("net: hold instance lock during NETDEV_REGISTER/UP")
> Signed-off-by: Faicker Mo <faicker.mo@xxxxxxxxxxxx>

...

Unfortunately this patch does not apply: it seems that somehow all the tabs
were converted into spaces.

> @@ -565,7 +565,7 @@ static int net_failover_slave_register(struct net_device *slave_dev,
>         dev_close(slave_dev);

Claude Code flags that that this needs to be changed to netif_close()

>  err_dev_open:
>         dev_put(slave_dev);
> -       dev_set_mtu(slave_dev, orig_mtu);
> +       netif_set_mtu(slave_dev, orig_mtu);
>  done:
>         return err;
>  }

-- 
pw-bot: changes-requested