Re: [PATCH-next] Fix unintentional integer overflow

["Sundararaju, Sathishkumar" <sasundar@xxxxxxx>]

On 10/3/2024 12:44 PM, Advait Dhamorikar wrote:

> Fix overflow issue by casting uint8_t to uint64_t in JPEG
> instance multiplication.
>     
    Thank you for the fix, u8 isn't the default it is usually treated as
    int, is it okay to mention "fix shift-count-overflow in.."

or something else of your choice , but not u8. And if possible, please align the end of commit description on all lines closer to each other (only where possible, else it is okay).

drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c:361:12: error: left shift count >= width of type [-Werror=shift-count-overflow]
  361 |  mask = (1 << 32)  - 1;

Regards,

Sathish

> The _expression_'s value may not be what the programmer intended,
> because the _expression_ is evaluated using
> a narrow (i.e. few bits) integer type.
>
> Fixes: f0b19b84d391 ("drm/amdgpu: add amdgpu_jpeg_sched_mask debugfs")
> Signed-off-by: Advait Dhamorikar <advaitdhamorikar@xxxxxxxxx>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c
> index 95e2796919fc..b6f0435f56ba 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c
> @@ -357,7 +357,7 @@ static int amdgpu_debugfs_jpeg_sched_mask_set(void *data, u64 val)
>  	if (!adev)
>  		return -ENODEV;
>  
> -	mask = (1 << (adev->jpeg.num_jpeg_inst * adev->jpeg.num_jpeg_rings)) - 1;
> +	mask = ((uint64_t)1 << (adev->jpeg.num_jpeg_inst * adev->jpeg.num_jpeg_rings)) - 1;
>  	if ((val & mask) == 0)
>  		return -EINVAL;
>  
>