Re: [PATCHv3] drm: zynqmp_dp: Fix integer overflow in zynqmp_dp_rate_get()

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

Ho Karol,

Thank you for the patch.

On Sun, Dec 15, 2024 at 01:53:55PM +0100, Karol Przybylski wrote:
> This patch fixes a potential integer overflow in the zynqmp_dp_rate_get()
> 
> The issue comes up when the expression
> drm_dp_bw_code_to_link_rate(dp->test.bw_code) * 10000 is evaluated using 32-bit
> Now the constant is a compatible 64-bit type.
> 
> Resolves coverity issues: CID 1636340 and CID 1635811
> 
> Cc: stable@vger.kernel.org
> Fixes: 28edaacb821c6 ("drm: zynqmp_dp: Add debugfs interface for compliance testing")
> Signed-off-by: Karol Przybylski <karprzy7@gmail.com>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
> Changes from previous versions:
> Added Fixes tag
> Added Cc for stable kernel version
> Fixed formatting
> 
>  drivers/gpu/drm/xlnx/zynqmp_dp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
> index 25c5dc61ee88..56a261a40ea3 100644
> --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
> +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
> @@ -2190,7 +2190,7 @@ static int zynqmp_dp_rate_get(void *data, u64 *val)
>  	struct zynqmp_dp *dp = data;
>  
>  	mutex_lock(&dp->lock);
> -	*val = drm_dp_bw_code_to_link_rate(dp->test.bw_code) * 10000;
> +	*val = drm_dp_bw_code_to_link_rate(dp->test.bw_code) * 10000ULL;
>  	mutex_unlock(&dp->lock);
>  	return 0;
>  }

-- 
Regards,

Laurent Pinchart