Re: [PATCH v2] media: sun8i-a83t-mipi-csi2: Use V4L2 subdev active state

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The active state lock is leaked in the error path of `pm_runtime_resume_and_get()` within `sun8i_a83t_mipi_csi2_s_stream()`.
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commit 1aff86a32a5202665d5639183ff47ad585d7b58e
Author: Arash Golgol <arash.golgol@gmail.com>
Subject: media: sun8i-a83t-mipi-csi2: Use V4L2 subdev active state

This commit updates the sun8i-a83t-mipi-csi2 driver to use the V4L2 subdev
active state API. This simplifies format storage and replaces the bridge lock
with the state lock.

> diff --git a/drivers/media/platform/sunxi/sun8i-a83t-mipi-csi2/sun8i_a83t_mipi_csi2.c b/drivers/media/platform/sunxi/sun8i-a83t-mipi-csi2/sun8i_a83t_mipi_csi2.c
> index dbc51daa4fe37..743bc86bfeabe 100644
> --- a/drivers/media/platform/sunxi/sun8i-a83t-mipi-csi2/sun8i_a83t_mipi_csi2.c
> +++ b/drivers/media/platform/sunxi/sun8i-a83t-mipi-csi2/sun8i_a83t_mipi_csi2.c
[ ... ]
> @@ -215,8 +216,12 @@ static int sun8i_a83t_mipi_csi2_s_stream(struct v4l2_subdev *subdev, int on)
>  	unsigned long pixel_rate;
>  	int ret;
>  
> -	if (!source_subdev)
> -		return -ENODEV;
> +	state = v4l2_subdev_lock_and_get_active_state(subdev);
> +
> +	if (!source_subdev) {
> +		ret = -ENODEV;
> +		goto unlock;
> +	}
>  
>  	if (!on) {
>  		v4l2_subdev_call(source_subdev, video, s_stream, 0);

Does this code leak the active state lock if the subsequent runtime PM resume
fails?

Looking at the unmodified code that immediately follows this hunk in
sun8i_a83t_mipi_csi2_s_stream():

	/* Runtime PM */

	ret = pm_runtime_resume_and_get(dev);
	if (ret < 0)
		return ret;

Since the state lock is now acquired at the beginning of the function,
if pm_runtime_resume_and_get() returns a negative value, it directly returns
to the caller.

Because it bypasses the "goto unlock" path, the state lock remains acquired,
which could cause a deadlock on any subsequent attempt to access the active
state or start the stream.

Should this error path be updated to "goto unlock" so the lock is properly
released?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260515144335.61323-1-arash.golgol@gmail.com?part=1