diff mbox series

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

Message ID 20210719200827.1507276-4-danielhb413@gmail.com
State New
Headers show
Series DEVICE_UNPLUG_ERROR QAPI event | expand

Commit Message

Daniel Henrique Barboza July 19, 2021, 8:08 p.m. UTC 
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(-)

Comments

Markus Armbruster Aug. 7, 2021, 1:41 p.m. UTC | #1 
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>
David Gibson Aug. 9, 2021, 3:39 a.m. UTC | #2 
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.
diff mbox series

Patch

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