Hi Tyrel,
> The pci_bus->bridge reference may no longer be valid after
> pci_bus_remove() resulting in passing a bad value to device_unregister()
> for the associated bridge device.
>
> Store the host_bridge reference in a separate variable prior to
> pci_bus_remove().
>
The patch certainly seems to do what you say. I'm not really up on the
innards of PCI, so I'm struggling to figure out by what code path
pci_bus_remove() might invalidate pci_bus->bridge? A quick look at
pci_remove_bus was not very illuminating but I didn't chase down every
call it made.
Kind regards,
Daniel
> Fixes: 7340056567e3 ("powerpc/pci: Reorder pci bus/bridge unregistration
> during PHB removal")
> Signed-off-by: Tyrel Datwyler <tyr...@linux.ibm.com>
> ---
> arch/powerpc/platforms/pseries/pci_dlpar.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/platforms/pseries/pci_dlpar.c
> b/arch/powerpc/platforms/pseries/pci_dlpar.c
> index f9ae17e8a0f4..a8f9140a24fa 100644
> --- a/arch/powerpc/platforms/pseries/pci_dlpar.c
> +++ b/arch/powerpc/platforms/pseries/pci_dlpar.c
> @@ -50,6 +50,7 @@ EXPORT_SYMBOL_GPL(init_phb_dynamic);
> int remove_phb_dynamic(struct pci_controller *phb)
> {
> struct pci_bus *b = phb->bus;
> + struct pci_host_bridge *host_bridge = to_pci_host_bridge(b->bridge);
> struct resource *res;
> int rc, i;
>
> @@ -76,7 +77,8 @@ int remove_phb_dynamic(struct pci_controller *phb)
> /* Remove the PCI bus and unregister the bridge device from sysfs */
> phb->bus = NULL;
> pci_remove_bus(b);
> - device_unregister(b->bridge);
> + host_bridge->bus = NULL;
> + device_unregister(&host_bridge->dev);
>
> /* Now release the IO resource */
> if (res->flags & IORESOURCE_IO)
> --
> 2.27.0
