Re: [PATCH v1 15/25] PCI: generic: Free resource list close to where it's allocated

Bjorn Helgaas
2016-06-21T15:14:07Z

On Mon, Jun 20, 2016 at 06:22:40PM +0100, Lorenzo Pieralisi wrote:
> On Mon, Jun 20, 2016 at 09:56:45AM -0700, Tyler Baker wrote:
> > Hi Bjorn,
> >
> > On 6 June 2016 at 16:06, Bjorn Helgaas <bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> wrote:
> > > Previously we allocated the PCI resource list in
> > > gen_pci_parse_request_of_pci_ranges(), but if we had an error, we freed it
> > > on error in gen_pci_init().
> > >
> > > Reorder gen_pci_init() so we can take care of error path cleanup in
> > > gen_pci_parse_request_of_pci_ranges() instead.
> > >
> > > Signed-off-by: Bjorn Helgaas <bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
> >
> > The kernelci.org bot has reported[0] new qemu-aarch64
> > (arm64-defconfig) boot failures[1][2] in next-20160620. I've
> > bisected[3] this boot failure down to this patch, and confirmed
> > reverting it on top of next-20160620 resolves the boot issue.
> >
> > I have not investigated further, but you can easily reproduce[4] the
> > boot failure on an x86 host running qemu-system-aarch64 (I'm running
> > qemu-system 2.6).
>
> That's most likely because pci_ecam_create() requires the bus_range
> resource (its busr parameter) to be initialized when it is called
> and that's not the case after this patch is applied if I read it
> correctly.
>
> It is probably a NULL pointer dereference in pci_ecam_create().

Yep, thanks everybody, I dropped that ill-considered patch altogether.

> > [0] https://kernelci.org/boot/all/job/next/kernel/next-20160620/
> > [1] https://storage.kernelci.org/next/next-20160620/arm64-defconfig/lab-cambridge/boot-apm-mustang-kvm-guest.txt
> > [2] https://storage.kernelci.org/next/next-20160620/arm64-defconfig/lab-tbaker/boot-qemu-aarch64,legacy.txt
> > [3] http://hastebin.com/segiruribu.vbs
> > [4] http://hastebin.com/dafuzicuyi.avrasm
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> >
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel