Hi Michael,
On Wed, Nov 28, 2018 at 6:00 AM Michael Ellerman <m...@ellerman.id.au> wrote:
>
> Radu Rendec <radu.ren...@gmail.com> writes:
> >
> > The assumption in arch_teardown_msi_irqs() is wrong and results in a
> > function call on a NULL pointer. An example of how this can happen is
> > included in the actual patch header. In my case, it happens when the PCI
> > hardware is configured during kernel start-up, because my controller
> > doesn't support MSI and the ops are NULL.
>
> What hardware are you on?
I'm on Freescale MPC8378 - old stuff, but still going strong :)
The MSI capable device is a Broadcom PEX 8613 (a 3-port PCIe switch).
> > I'm proposing the attached patch to fix the problem. It basically just
> > checks the pointer before the function call.
>
> Yeah that patch looks good to me.
>
> I suspect this bug was introduced in:
>
> 6b2fd7efeb88 ("PCI/MSI/PPC: Remove arch_msi_check_device()")
>
> Previously we had that check routine which would run before any of the
> MSI setup had been done, and so if there were no MSI ops then we bailed
> out early and didn't call teardown.
>
> I guess since then (2014) we haven't tested an MSI capable device on a
> system that isn't MSI capable?
Thanks for looking into this. You're probably right, it really looks like
that patch could have introduced this bug.
Cheers,
Radu
