[Intel-wired-lan] [PATCH net] ice: Fix race during aux device (un)plugging

[Ivan Vecera <ivecera@redhat.com>]

On Wed, 20 Apr 2022 09:36:43 +0300
Leon Romanovsky <leon@kernel.org> wrote:

> > ice_send_event_to_aux() takes aux device lock. ice_unplug_aux_dev()
> > calls auxiliary_device_delete() that calls device_del(). device_del()
> > takes device_lock() prior kill_device(). So if ice_send_event_to_aux()
> > is in progress then device_del() waits for its completion.  
> 
> Not really, you nullify pf->adev without any lock protection and
> ice_send_event_to_aux() will simply crash.
> 
>  CPU#1          	|   CPU#2
> 			| ice_send_event_to_aux
>  ice_unplug_aux_dev()   | ...
>  ...                    | 
>  pf->adev = NULL;       | 
>       			| device_lock(&pf->adev->dev); <--- crash here.
> 
> Thanks

You are right, the window is very tiny but it's still there.
Will send v2.

Thanks,
Ivan