Re: [Qemu-devel] [PATCH v4 01/11] qga-win: fix crashes when PCI info cannot be retrived

["Tomáš Golembiovský" <tgolembi@redhat.com>]

On Thu, 4 Oct 2018 17:21:32 +0400
Marc-André Lureau <marcandre.lureau@redhat.com> wrote:

> Hi
> On Thu, Oct 4, 2018 at 3:22 PM Tomáš Golembiovský <tgolembi@redhat.com> wrote:
> >
> > The guest-get-fsinfo command collects also information about PCI
> > controller where the disk is attached. When this fails for some reasons
> > it tries to return just the partial information. However in certain
> > cases the pointer to the structure was not initialized and was set to
> > NULL. This breaks the serializer and leads to a crash of the guest agent.
> >
> > Signed-off-by: Tomáš Golembiovský <tgolembi@redhat.com>
> > ---
> >  qga/commands-win32.c | 27 ++++++++++++++++++++++-----
> >  1 file changed, 22 insertions(+), 5 deletions(-)
> >
> > diff --git a/qga/commands-win32.c b/qga/commands-win32.c
> > index 98d9735389..9c959122d9 100644
> > --- a/qga/commands-win32.c
> > +++ b/qga/commands-win32.c
> > @@ -633,15 +633,32 @@ static GuestDiskAddressList *build_guest_disk_info(char *guid, Error **errp)
> >           * https://technet.microsoft.com/en-us/library/ee851589(v=ws.10).aspx */
> >          if (DeviceIoControl(vol_h, IOCTL_SCSI_GET_ADDRESS, NULL, 0, scsi_ad,
> >                              sizeof(SCSI_ADDRESS), &len, NULL)) {
> > +            Error *local_err = NULL;
> >              disk->unit = addr.Lun;
> >              disk->target = addr.TargetId;
> >              disk->bus = addr.PathId;
> > -            disk->pci_controller = get_pci_info(name, errp);
> > +            g_debug("unit=%lld target=%lld bus=%lld",
> > +                disk->unit, disk->target, disk->bus);
> > +            disk->pci_controller = get_pci_info(name, &local_err);
> > +
> > +            if (local_err) {
> > +                g_debug("failed to get PCI controller info: %s",
> > +                    error_get_pretty(local_err));
> > +                error_free(local_err);
> > +            } else if (disk->pci_controller != NULL) {
> > +                g_debug("pci: domain=%lld bus=%lld slot=%lld function=%lld",
> > +                    disk->pci_controller->domain,
> > +                    disk->pci_controller->bus,
> > +                    disk->pci_controller->slot,
> > +                    disk->pci_controller->function);
> > +            }
> >          }
> > -        /* We do not set error in this case, because we still have enough
> > -         * information about volume. */
> > -    } else {
> > -         disk->pci_controller = NULL;
> > +    }
> > +    /* We do not set error in case pci_controller is NULL, because we still
> > +     * have enough information about volume. */
> > +    if (disk->pci_controller == NULL) {
> > +        g_debug("no PCI controller info");
> > +        disk->pci_controller = g_malloc0(sizeof(GuestPCIAddress));
> >      }  
> 
> Shouldn't pci-controller be made optional in the schema instead?

It should, but that requires API change. 
Eric suggested that previously too:

https://lists.gnu.org/archive/html/qemu-devel/2018-06/msg08599.html

I will do that in next version.

    Tomas

> 
> >
> >      list = g_malloc0(sizeof(*list));
> > --
> > 2.19.0
> >  


-- 
Tomáš Golembiovský <tgolembi@redhat.com>