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

[David Gibson]

On Sat, Aug 07, 2021 at 03:41:52PM +0200, Markus Armbruster wrote:
> 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:

I am, given how briefly this message has even existed - and through
all that time it would have crashed if you tried.

> Reviewed-by: Markus Armbruster <armbru@redhat.com>

Folded into my tree.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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