Re: [Xen-devel] [PATCH] xen-netfront: Fix hang on device removal

[Boris Ostrovsky]

On 02/28/2018 07:23 AM, Jason Andryuk wrote:
> A toolstack may delete the vif frontend and backend xenstore entries
> while xen-netfront is in the removal code path.  In that case, the
> checks for xenbus_read_driver_state would return XenbusStateUnknown, and
> xennet_remove would hang indefinitely.  This hang prevents system
> shutdown.
>
> xennet_remove must be able to handle XenbusStateUnknown, and
> netback_changed must also wake up the wake_queue for that state as well.
>
> Fixes: 5b5971df3bc2 ("xen-netfront: remove warning when unloading module")
>
> Signed-off-by: Jason Andryuk <jandryuk@xxxxxxxxx>
> Cc: Eduardo Otubo <otubo@xxxxxxxxxx>

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>