Re: [PATCH for-6.2 v6 3/7] spapr_drc.c: do not error_report() when drc->dev->id == NULL

[Markus Armbruster <armbru@redhat.com>]

Daniel Henrique Barboza <danielhb413@gmail.com> writes:

> The error_report() call in drc_unisolate_logical() is not considering
> that drc->dev->id can be NULL, and the underlying functions error_report()
> calls to do its job (vprintf(), g_strdup_printf() ...) has undefined
> behavior when trying to handle "%s" with NULL arguments.
>
> Besides, there is no utility into reporting that an unknown device was
> rejected by the guest.
>
> Reviewed-by: Greg Kurz <groug@kaod.org>
> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
> ---
>  hw/ppc/spapr_drc.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c
> index a2f2634601..a4d9496f76 100644
> --- a/hw/ppc/spapr_drc.c
> +++ b/hw/ppc/spapr_drc.c
> @@ -167,8 +167,11 @@ static uint32_t drc_unisolate_logical(SpaprDrc *drc)
>              }
>  
>              drc->unplug_requested = false;
> -            error_report("Device hotunplug rejected by the guest "
> -                         "for device %s", drc->dev->id);
> +
> +            if (drc->dev->id) {
> +                error_report("Device hotunplug rejected by the guest "
> +                             "for device %s", drc->dev->id);
> +            }
>  
>              /*
>               * TODO: send a QAPI DEVICE_UNPLUG_ERROR event when

This differs from PATCH 1 and 2 in that it actually fixes a crash bug.

The alternative is something like

               error_report("Device hotunplug rejected by the guest "
                            "for device %s", drc->dev->id ?: "");

If the maintainer is okay with dropping the message when the device has
no ID, then so am I:
Reviewed-by: Markus Armbruster <armbru@redhat.com>