Messages in this thread | | | From | Tong Zhang <> | Date | Tue, 11 May 2021 10:17:12 -0700 | Subject | Re: [PATCH] misc: alcor_pci: fix null-ptr-deref when there is no PCI bridge |
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On Tue, May 11, 2021 at 12:03 AM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > On Mon, May 10, 2021 at 03:20:02PM -0700, Tong Zhang wrote: > > On Mon, May 10, 2021 at 7:36 AM Greg Kroah-Hartman > > <gregkh@linuxfoundation.org> wrote: > > > > > > On Mon, Apr 26, 2021 at 06:07:27PM -0400, Tong Zhang wrote: > > > > the PCI bridge might be NULL, so we'd better check before use it > > > > > > I do not understand, how can pci ever be NULL? There is only 1 way this > > > > Hi Greg, > > I think the problem is with > > priv->parent_pdev = pdev->bus->self > > where bus->self can be NULL. when bus->self is NULL, calling > > How can bus->self be NULL?
Hi Greg, Please correct me if I am wrong, when bus->self is not NULL, it means there is a bridge, However, a device can be directly attached to the port on the root complex. In this case, the bus->self is NULL.
> Did you see this on a real system? How did you duplicate the error > listed here? I did this in QEMU. If QEMU is considered not real, then I haven't seen an alcor controller configured in this way in a real system. That being said, this kind of configuration is still legit IMHO. Best, - Tong
> thanks, > > greg k-h
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