[PATCH] drm/amd/display: Fix pointer dereferenced before checking

[Alex Deucher]

Applied both patches.  Thanks!

Alex

On Thu, Mar 24, 2022 at 9:46 AM Haowen Bai <baihaowen at meizu.com> wrote:
>
> The value actual_pix_clk_100Hz is dereferencing pointer pix_clk_params
> before pix_clk_params is being null checked. Fix this by assigning
> pix_clk_params->requested_pix_clk_100hz to actual_pix_clk_100Hz only if
> pix_clk_params is not NULL, otherwise just NULL.
>
> Signed-off-by: Haowen Bai <baihaowen at meizu.com>
> ---
>  drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c b/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
> index 2c7eb98..4db45bb 100644
> --- a/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
> +++ b/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
> @@ -1162,7 +1162,7 @@ static uint32_t dcn3_get_pix_clk_dividers(
>                 struct pixel_clk_params *pix_clk_params,
>                 struct pll_settings *pll_settings)
>  {
> -       unsigned long long actual_pix_clk_100Hz = pix_clk_params->requested_pix_clk_100hz;
> +       unsigned long long actual_pix_clk_100Hz = pix_clk_params ? pix_clk_params->requested_pix_clk_100hz : 0;
>         struct dce110_clk_src *clk_src;
>
>         clk_src = TO_DCE110_CLK_SRC(cs);
> --
> 2.7.4
>