Re: [PATCH 2/2] media: videobuf2: add WARN_ON if bytesused is bigger than buffer length

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Wed, Nov 10, 2021 at 09:58:02AM +0100, Hans Verkuil wrote:
> On 08/11/2021 20:39, Dafna Hirschfeld wrote:
> > In function vb2_set_plane_payload, report if the
> > given bytesused is bigger than the buffer size.
> > 
> > Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
> > ---
> >  include/media/videobuf2-core.h | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
> > index 2467284e5f26..ffaa1f3361c3 100644
> > --- a/include/media/videobuf2-core.h
> > +++ b/include/media/videobuf2-core.h
> > @@ -1155,8 +1155,10 @@ static inline void *vb2_get_drv_priv(struct vb2_queue *q)
> >  static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
> >  				 unsigned int plane_no, unsigned long size)
> >  {
> > -	if (plane_no < vb->num_planes)
> > +	if (plane_no < vb->num_planes) {
> > +		WARN_ON(size > vb->planes[plane_no].length);
> 
> I would change this to:
> 
> 		/*
> 		 * size must never be larger than the buffer length, so
> 		 * warn and clamp to the buffer length if that's the case.
> 		 */
> 		if (WARN_ON(size > vb->planes[plane_no].length))
> 			size = vb->planes[plane_no].length;

Should this also be a WARN_ON_ONCE() ? If it occurs once there's a large
risk it will occur very frequently, and flood the kernel log.

> >  		vb->planes[plane_no].bytesused = size;
> > +	}
> >  }
> >  
> >  /**

-- 
Regards,

Laurent Pinchart