On Tue, Apr 21, 2020 at 06:22:56PM +0200, Ard Biesheuvel wrote:
> When resizing a BAR, pci_reassign_bridge_resources() is invoked to
> bring the bridge windows of parent bridges in line with the new BAR
> assignment.
>
> This assumes that the device whose BAR is being resized lives on a
> subordinate bus, but this is not necessarily the case. A device may
> live on the root bus, in which case dev->bus->self is NULL, and
> passing a NULL pci_dev pointer to pci_reassign_bridge_resources()
> will cause it to crash.
>
> So let's make the call to pci_reassign_bridge_resources() conditional
> on whether dev->bus->self is non-NULL in the first place.
>
> Fixes: 8bb705e3e79d84e7 ("PCI: Add pci_resize_resource() for resizing BARs")
> Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Applied with Christian's reviewed-by to pci/resource for v5.8, thanks!
> ---
> drivers/pci/setup-res.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
> index d8ca40a97693..d21fa04fa44d 100644
> --- a/drivers/pci/setup-res.c
> +++ b/drivers/pci/setup-res.c
> @@ -439,10 +439,11 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size)
> res->end = res->start + pci_rebar_size_to_bytes(size) - 1;
>
> /* Check if the new config works by trying to assign everything. */
> - ret = pci_reassign_bridge_resources(dev->bus->self, res->flags);
> - if (ret)
> - goto error_resize;
> -
> + if (dev->bus->self) {
> + ret = pci_reassign_bridge_resources(dev->bus->self, res->flags);
> + if (ret)
> + goto error_resize;
> + }
> return 0;
>
> error_resize:
> --
> 2.17.1
>
