Re: [PATCH] acpi: pci_root: fix NULL pointer deref after resume from suspend

Rafael J. Wysocki
2009-09-29T23:29:53Z

On Tuesday 29 September 2009, Alex Chiang wrote:
> * Rafael J. Wysocki <rjw@sisk.pl>:
> > On Tuesday 29 September 2009, Danny Feng wrote:
> > > Is there any cases that pdev->subordinate is NULL while pdev is bridge
> > > device?
> > > From pci_slot.c::walk_p2p_bridge, there's code like following:
> > >
> > > dev = pci_get_slot(pci_bus, PCI_DEVFN(device, function));
> > > if (!dev || !dev->subordinate)
> > > goto out;
> > >
> > > It looks like dev->subordinate can be NULL even if in p2p
> > > bridge, right?
>
> In the code you post above, that results from doing an ACPI
> namespace walk, which will definitely find non-bridge devices.
>
> > Right, in general, but in this particular case each device we
> > inspect is supposed to be a parent of another device, which
> > implies that there's a bus below it (given that it's a PCI
> > device).
>
> Right, that's why I'm surprised that my assumption broke. But now
> that I see that a dock device is involved, maybe that's not so
> surprising.

Yeah. Still, I'd like to know the root cause.

Thanks,
Rafael