Re: [PATCH 05/10] Input: synaptics-rmi4 - block s_input when F54 queue is busy

[Hans Verkuil <hverkuil+cisco@kernel.org>]

On 26/06/2026 07:17, Dmitry Torokhov wrote:
> Changing the input (diagnostic report type) mid-stream changes the
> report size. Since V4L2 buffers are allocated based on the size at
> stream start, changing the input while streaming could lead to a
> heap buffer overflow if the new size is larger than the allocated
> buffers.
> 
> Prevent this by blocking VIDIOC_S_INPUT with -EBUSY if the V4L2 queue
> is busy (streaming).
> 
> Fixes: 3a762dbd5347 ("[media] Input: synaptics-rmi4 - add support for F54 diagnostics")
> Cc: stable@vger.kernel.org
> Assisted-by: Antigravity:gemini-3.5-flash
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Reviewed-by: Hans Verkuil <hverkuil+cisco@kernel.org>

Regards,

	Hans

> ---
>  drivers/input/rmi4/rmi_f54.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/rmi4/rmi_f54.c b/drivers/input/rmi4/rmi_f54.c
> index aebe74d2032c..e86dfc9ce7d9 100644
> --- a/drivers/input/rmi4/rmi_f54.c
> +++ b/drivers/input/rmi4/rmi_f54.c
> @@ -445,7 +445,12 @@ static int rmi_f54_set_input(struct f54_data *f54, unsigned int i)
>  
>  static int rmi_f54_vidioc_s_input(struct file *file, void *priv, unsigned int i)
>  {
> -	return rmi_f54_set_input(video_drvdata(file), i);
> +	struct f54_data *f54 = video_drvdata(file);
> +
> +	if (vb2_is_busy(&f54->queue))
> +		return -EBUSY;
> +
> +	return rmi_f54_set_input(f54, i);
>  }
>  
>  static int rmi_f54_vidioc_g_input(struct file *file, void *priv,