Re: [PATCH] media: v4l2-subdev: Fix error check in v4l2_subdev_get_frame_desc_passthrough()

[Jacopo Mondi <jacopo.mondi@ideasonboard.com>]

Hello Chen Ni,

On Fri, Mar 13, 2026 at 02:39:46PM +0800, Chen Ni wrote:
> Use IS_ERR() and PTR_ERR() to properly handle the error return from
> media_pad_remote_pad_unique(), which returns ERR_PTR() on failure but
> never NULL. The previous code only checked for NULL, leading to invalid
> pointer dereference.
>
> Fixes: a564839e630c ("media: subdev: Add v4l2_subdev_get_frame_desc_passthrough helper")
> Signed-off-by: Chen Ni <nichen@iscas.ac.cn>

Seems like a bug indeed, thanks!

Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

> ---
>  drivers/media/v4l2-core/v4l2-subdev.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 9efd14d4026f..7cb17e0a5617 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -2585,10 +2585,10 @@ int v4l2_subdev_get_frame_desc_passthrough(struct v4l2_subdev *sd,
>
>  			if (!have_source_fd) {
>  				remote_source_pad = media_pad_remote_pad_unique(local_sink_pad);
> -				if (!remote_source_pad) {
> +				if (IS_ERR(remote_source_pad)) {
>  					dev_dbg(dev, "Failed to find remote pad for sink pad %u\n",
>  						local_sink_pad->index);
> -					ret = -EINVAL;
> +					ret = PTR_ERR(remote_source_pad);
>  					goto out_unlock;
>  				}
>
> --
> 2.25.1
>
>