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

[Rajat Jain]

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. 

Thanks,

Rajat

> -----Original Message-----
> From: linux-pci-owner@xxxxxxxxxxxxxxx [mailto:linux-pci-
> owner@xxxxxxxxxxxxxxx] On Behalf Of Andreas Noever
> Sent: Monday, June 09, 2014 2:04 PM
> To: linux-kernel@xxxxxxxxxxxxxxx; Bjorn Helgaas; linux-pci@xxxxxxxxxxxxxxx
> 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@xxxxxxxxx>
> ---
>  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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