Re: [PATCH 1/1] xen/manage: enable C_A_D to force reboot

[Jürgen Groß <jgross@xxxxxxxx>]

On 14.05.20 01:34, Dongli Zhang wrote:
> The systemd may be configured to mask ctrl-alt-del via "systemctl mask
> ctrl-alt-del.target". As a result, the pv reboot would not work as signal
> is ignored.
>
> This patch always enables C_A_D before the call of ctrl_alt_del() in order
> to force the reboot.
Hmm, I'm not sure this is a good idea.

Suppose a guest admin is doing a critical update and wants to avoid a
sudden reboot in between. By masking the reboot this would be possible,
with your patch it isn't.

In case a reboot is really mandatory it would still be possible to just
kill the guest.

I'm not completely opposed to the patch, but I think this is a change
which should not be done easily.


Juergen

> Reported-by: Rose Wang <rose.wang@xxxxxxxxxx>
> Cc: Joe Jin <joe.jin@xxxxxxxxxx>
> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> Signed-off-by: Dongli Zhang <dongli.zhang@xxxxxxxxxx>
> ---
>   drivers/xen/manage.c | 7 +++++++
>   1 file changed, 7 insertions(+)
>
> diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
> index cd046684e0d1..3190d0ecb52e 100644
> --- a/drivers/xen/manage.c
> +++ b/drivers/xen/manage.c
> @@ -204,6 +204,13 @@ static void do_poweroff(void)
>   static void do_reboot(void)
>   {
>         shutting_down = SHUTDOWN_POWEROFF; /* ? */
> +       /*
> +        * The systemd may be configured to mask ctrl-alt-del via
> +        * "systemctl mask ctrl-alt-del.target". As a result, the pv reboot
> +        * would not work. To enable C_A_D would force the reboot.
> +        */
> +       C_A_D = 1;
> +
>         ctrl_alt_del();
>   }
>