Re: [PATCH] drivers: gpio: amd8111: Fix PCI device reference count leak

[Bartosz Golaszewski <brgl@xxxxxxxx>]

On Tue, Nov 22, 2022 at 1:17 PM Xiongfeng Wang
<wangxiongfeng2@xxxxxxxxxx> wrote:
>
> for_each_pci_dev() is implemented by pci_get_device(). The comment of
> pci_get_device() says that it will increase the reference count for the
> returned pci_dev and also decrease the reference count for the input
> pci_dev @from if it is not NULL.
>
> If we break for_each_pci_dev() loop with pdev not NULL, we need to call
> pci_dev_put() to decrease the reference count. Add the missing
> pci_dev_put() after the 'out' label. Since pci_dev_put() can handle NULL
> input parameter, there is no problem for the 'Device not found' branch.
> For the normal path, add pci_dev_put() in amd_gpio_exit().
>
> Fixes: f942a7de047d ("gpio: add a driver for GPIO pins found on AMD-8111 south bridge chips")
> Signed-off-by: Xiongfeng Wang <wangxiongfeng2@xxxxxxxxxx>
> ---
>  drivers/gpio/gpio-amd8111.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpio/gpio-amd8111.c b/drivers/gpio/gpio-amd8111.c
> index 14e6b3e64add..6f3ded619c8b 100644
> --- a/drivers/gpio/gpio-amd8111.c
> +++ b/drivers/gpio/gpio-amd8111.c
> @@ -226,7 +226,10 @@ static int __init amd_gpio_init(void)
>                 ioport_unmap(gp.pm);
>                 goto out;
>         }
> +       return 0;
> +
>  out:
> +       pci_dev_put(pdev);
>         return err;
>  }
>
> @@ -234,6 +237,7 @@ static void __exit amd_gpio_exit(void)
>  {
>         gpiochip_remove(&gp.chip);
>         ioport_unmap(gp.pm);
> +       pci_dev_put(gp.pdev);
>  }
>
>  module_init(amd_gpio_init);
> --
> 2.20.1
>

Applied for fixes, thanks!

Bart