Re: [PATCH 1/1] PCI: check return value of pci_find_ext_capability

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Sun, Apr 23, 2017 at 10:00:20PM +0800, Pan Bian wrote:
> From: Pan Bian <bianpan2016@163.com>
> 
> Function pci_find_ext_capability() will returns 0 on failure, and its
> return value should be checked before it is used. However, in function
> pcie_port_enable_msix(), its return value is not checked. This patch
> adds the check.
> 
> Signed-off-by: Pan Bian <bianpan2016@163.com>
> ---
>  drivers/pci/pcie/portdrv_core.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> index cea504f..001951d 100644
> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -103,6 +103,8 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
>  		 * interrupt message."
>  		 */
>  		pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
> +		if (!pos)
> +			goto out_free_irqs;

I don't think this can happen because get_port_device_capability() will
enumerate this capability and only if it exists, set PCIE_PORT_SERVICE_AER.