Re: [PATCH v2] staging: most: video: prevent probes during component exit

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Nov 26, 2025 at 10:59:10AM -0500, Pavan Kumar Yalagada wrote:
> Previously, comp_probe_channel() would always add a new device to
> video_devices, even if comp_exit() was running. This caused
> BUG_ON(!list_empty(&video_devices)) in comp_exit() because
> the list could be repopulated during teardown.
> 
> This patch adds a global static flag `comp_exiting`:
> 
> - Set `comp_exiting = true` at the start of comp_exit()
>   to signal shutdown.
> - Check `comp_exiting` at the start of comp_probe_channel()
>   and return -EBUSY if set.
> 
> This prevents new devices from being added while the component
> is exiting, ensuring video_devices stays empty and avoiding
> BUG_ON triggers.
> 
> Signed-off-by: Pavan Kumar Yalagada <pavankumaryalagada@gmail.com>
> ---
>  drivers/staging/most/video/video.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/most/video/video.c b/drivers/staging/most/video/video.c
> index 32f71d9a9cf7..96366b7a0e29 100644
> --- a/drivers/staging/most/video/video.c
> +++ b/drivers/staging/most/video/video.c
> @@ -60,6 +60,8 @@ static inline struct comp_fh *to_comp_fh(struct file *filp)
>  static LIST_HEAD(video_devices);
>  static DEFINE_SPINLOCK(list_lock);
>  
> +static bool comp_exiting;
> +
>  static inline bool data_ready(struct most_video_dev *mdev)
>  {
>  	return !list_empty(&mdev->pending_mbos);
> @@ -453,6 +455,9 @@ static int comp_probe_channel(struct most_interface *iface, int channel_idx,
>  			      struct most_channel_config *ccfg, char *name,
>  			      char *args)
>  {
> +	if (comp_exiting)
> +		return -EBUSY;

This will not work at all.

Also, you need to properly document a v2 patch.

thanks,

greg k-h