On Mon, Oct 30, 2023 at 01:42:18PM +0200, Andy Shevchenko wrote:
> Coverity complains that pointer in the pci_dev_for_each_resource()
> may be wrong, i.e. mighe be used for the out-of-bounds read.
>
> There is no actual issue right now, because we have another check
> afterwards and the out-of-bounds read is not being performed. In any
> case it's better code with this get fixed, hence the proposed change.
>
> As Jonas pointed out "It probably makes the code slightly less
> performant as res will now be checked for being not NULL (which will
> always be true), but I doubt it will be significant (or in any hot
> paths)."
>
> Fixes: 09cc90063240 ("PCI: Introduce pci_dev_for_each_resource()")
> Reported-by: Bjorn Helgaas <helgaas@xxxxxxxxxx>
> Closes: https://lore.kernel.org/r/20230509182122.GA1259567@bhelgaas
> Suggested-by: Jonas Gorski <jonas.gorski@xxxxxxxxx>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Thanks, Andy, I'll look at this soon after v6.7-rc1 (probably Nov 12).
> ---
> include/linux/pci.h | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 60ca768bc867..19adad23a204 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -2127,14 +2127,14 @@ int pci_iobar_pfn(struct pci_dev *pdev, int bar, struct vm_area_struct *vma);
> (pci_resource_end((dev), (bar)) ? \
> resource_size(pci_resource_n((dev), (bar))) : 0)
>
> -#define __pci_dev_for_each_res0(dev, res, ...) \
> - for (unsigned int __b = 0; \
> - res = pci_resource_n(dev, __b), __b < PCI_NUM_RESOURCES; \
> +#define __pci_dev_for_each_res0(dev, res, ...) \
> + for (unsigned int __b = 0; \
> + __b < PCI_NUM_RESOURCES && (res = pci_resource_n(dev, __b)); \
> __b++)
>
> -#define __pci_dev_for_each_res1(dev, res, __b) \
> - for (__b = 0; \
> - res = pci_resource_n(dev, __b), __b < PCI_NUM_RESOURCES; \
> +#define __pci_dev_for_each_res1(dev, res, __b) \
> + for (__b = 0; \
> + __b < PCI_NUM_RESOURCES && (res = pci_resource_n(dev, __b)); \
> __b++)
>
> #define pci_dev_for_each_resource(dev, res, ...) \
> --
> 2.40.0.1.gaa8946217a0b
>
