Re: [PATCH] media: qcom: camss: Fix pipeline lock leak in stop_streaming

[Bryan O'Donoghue <bryan.odonoghue@linaro.org>]

On 24/01/2026 07:17, Saikiran wrote:
> When a browser or application closes the camera, if any subdevice fails
> to stop streaming, the video_stop_streaming() function returns early
> without calling video_device_pipeline_stop(). This leaves the media
> pipeline permanently locked, preventing any other application from
> accessing the camera until reboot.
> 
> Symptom:
> --------
> 1. Open camera in browser (via pipewire/libcamera)
> 2. Close browser
> 3. Try to open camera in another app (e.g., qcam)
> 4. Error: "Pipeline handler in use by another process"
> 5. Camera remains locked until reboot
> 
> Root Cause:
> -----------
> In video_stop_streaming() at line 315-318:
> 
>    ret = v4l2_subdev_call(subdev, video, s_stream, 0);
>    if (ret) {
>        dev_err(...);
>        return;  // ❌ Early return without pipeline_stop()
>    }
> 
> This skips the critical cleanup at line 321:
>    video_device_pipeline_stop(vdev);
> 
> Solution:
> ---------
> Continue stopping all subdevices even if one fails, and ALWAYS call
> video_device_pipeline_stop() to release the pipeline lock. This
> ensures proper cleanup even in error cases.
> 
> The pipeline MUST be released when streaming stops, regardless of
> whether individual subdevices report errors. Failing to do so creates
> a permanent resource leak that can only be fixed by rebooting.
> 
> Fixes: Camera permanently locked after browser closes

You need to fix your Fixes: tag

Something like:

Fixes: 89013969e232 ("media: camss: sm8250: Pipeline starting and 
stopping for multiple virtual channels")

> Tested-on: Lenovo Yoga Slim 7x (Snapdragon X Elite, ov02c10 camera)
> Signed-off-by: Saikiran <bjsaikiran@gmail.com>
> ---
>   drivers/media/platform/qcom/camss/camss-video.c | 13 +++++++++----
>   1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/platform/qcom/camss/camss-video.c b/drivers/media/platform/qcom/camss/camss-video.c
> index 831486e14754..578c0ae3d997 100644
> --- a/drivers/media/platform/qcom/camss/camss-video.c
> +++ b/drivers/media/platform/qcom/camss/camss-video.c
> @@ -312,10 +312,15 @@ static void video_stop_streaming(struct vb2_queue *q)
>   
>   		ret = v4l2_subdev_call(subdev, video, s_stream, 0);
>   
> -		if (ret) {
> -			dev_err(video->camss->dev, "Video pipeline stop failed: %d\n", ret);
> -			return;
> -		}
> +		/*
> +		 * Don't return early on error - we must continue to stop
> +		 * remaining subdevices and release the pipeline lock to
> +		 * prevent the camera from being permanently locked.
> +		 */
> +		if (ret)
> +			dev_err(video->camss->dev,
> +				"Failed to stop subdev '%s': %d\n",
> +				subdev->name, ret);

if (ret) {
	// do stuff here
}

>   	}
>   
>   	video_device_pipeline_stop(vdev);

---
bod