Re: [PATCH 1/2] drm/panthor: Don't check the array stride on empty uobj arrays

[Steven Price <steven.price@arm.com>]

On 28/06/2024 15:55, Boris Brezillon wrote:
> The user is likely to leave all the drm_panthor_obj_array fields
> to zero when the array is empty, which will cause an EINVAL failure.
> 
> Fixes: 4bdca1150792 ("drm/panthor: Add the driver frontend block")
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>

Reviewed-by: Steven Price <steven.price@arm.com>

> ---
>  drivers/gpu/drm/panthor/panthor_drv.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
> index b8a84f26b3ef..b5e7b919f241 100644
> --- a/drivers/gpu/drm/panthor/panthor_drv.c
> +++ b/drivers/gpu/drm/panthor/panthor_drv.c
> @@ -86,15 +86,15 @@ panthor_get_uobj_array(const struct drm_panthor_obj_array *in, u32 min_stride,
>  	int ret = 0;
>  	void *out_alloc;
>  
> +	if (!in->count)
> +		return NULL;
> +
>  	/* User stride must be at least the minimum object size, otherwise it might
>  	 * lack useful information.
>  	 */
>  	if (in->stride < min_stride)
>  		return ERR_PTR(-EINVAL);
>  
> -	if (!in->count)
> -		return NULL;
> -
>  	out_alloc = kvmalloc_array(in->count, obj_size, GFP_KERNEL);
>  	if (!out_alloc)
>  		return ERR_PTR(-ENOMEM);