Re: [PATCH] fix: drivers/video: __screen_info_pci_dev: leaked pci_dev references in pci_get_base_class loop

[Helge Deller]

On 6/27/26 05:44, WenTao Liang wrote:
> In __screen_info_pci_dev(), the loop uses pci_get_base_class() with a
> non-NULL starting device pdev. Each iteration returns a new device
> reference but does not release the previous one. When a non-matching
> device is found, pdev is overwritten and the previous reference leaks.
> When no match is found, all acquired references are leaked.
>
> Add pci_dev_put(pdev) for non-matching devices before continuing the loop.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 036105e3a776 ("video: Provide screen_info_get_pci_dev() to find screen_info's PCI device")
> Signed-off-by: WenTao Liang <vulab@xxxxxxxxxxx>
> ---
>   drivers/video/screen_info_pci.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/video/screen_info_pci.c b/drivers/video/screen_info_pci.c
> index 8f34d8a74f09..c821101e9304 100644
> --- a/drivers/video/screen_info_pci.c
> +++ b/drivers/video/screen_info_pci.c
> @@ -123,6 +123,10 @@ static struct pci_dev *__screen_info_pci_dev(struct resource *res)
>   
>   	while (!r && (pdev = pci_get_base_class(PCI_BASE_CLASS_DISPLAY, pdev))) {
>   		r = pci_find_resource(pdev, res);
> +		if (!r) {
> +			pci_dev_put(pdev);
> +			pdev = NULL;
> +		}

Have you tested the code?
If pdev gets assigned NULL, doesn't that introduce an endless loop?
And, similar code is in amdgpu*  and google's framebuffer-coreboot.c files, so if
this is correct, don't they need fixing as well?

Helge