Re: [PATCH] PCI: Prevent NULL dereference during pciehp probe

[Guenter Roeck <linux@roeck-us.net>]

On Mon, Sep 15, 2014 at 10:20:41PM +0000, Rajat Jain wrote:
> Hello Bjorn,
> 
> I think this patch needs to be applied to all -stable branches (all the way back to 3.2).
> 
> I encounter this same issue on my platform that is running 3.14.y. 
> 
Bjorn,

can you send this to -stable, or is it ok if I do it ?

Thanks,
Guenter

> Thanks,
> 
> Rajat
> 
> > -----Original Message-----
> > From: linux-pci-owner@vger.kernel.org [mailto:linux-pci-
> > owner@vger.kernel.org] On Behalf Of Andreas Noever
> > Sent: Monday, June 09, 2014 2:04 PM
> > To: linux-kernel@vger.kernel.org; Bjorn Helgaas; linux-pci@vger.kernel.org
> > Cc: Andreas Noever
> > Subject: [PATCH] PCI: Prevent NULL dereference during pciehp probe
> > 
> > pciehp assumes that dev->subordinate exists. But we do not assign a bus if
> > we run out of bus numbers during enumeration. This leads to a NULL
> > dereference in init_slot (and other places).
> > 
> > Change pciehp_probe to return -ENODEV when no subordinate bus is
> > present.
> > 
> > Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
> > ---
> >  drivers/pci/hotplug/pciehp_core.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/drivers/pci/hotplug/pciehp_core.c
> > b/drivers/pci/hotplug/pciehp_core.c
> > index 0e0a2ff..e5abcaf 100644
> > --- a/drivers/pci/hotplug/pciehp_core.c
> > +++ b/drivers/pci/hotplug/pciehp_core.c
> > @@ -255,6 +255,13 @@ static int pciehp_probe(struct pcie_device *dev)
> >  	else if (pciehp_acpi_slot_detection_check(dev->port))
> >  		goto err_out_none;
> > 
> > +	if (!dev->port->subordinate) {
> > +		/* Can happen if we run out of bus numbers during probe */
> > +		dev_err(&dev->device,
> > +			"Hotplug bridge without secondary bus, ignoring\n");
> > +		goto err_out_none;
> > +	}
> > +
> >  	ctrl = pcie_init(dev);
> >  	if (!ctrl) {
> >  		dev_err(&dev->device, "Controller initialization failed\n");
> > --
> > 2.0.0
> > 
> > --
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