[PATCH] drm/amd/display: check dc_link before dereferencing

[Alex Deucher]

Applied.  Thanks!

On Tue, Feb 27, 2024 at 2:08 PM Melissa Wen <mwen at igalia.com> wrote:
>
> drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:6683 amdgpu_dm_connector_funcs_force()
> warn: variable dereferenced before check 'dc_link' (see line 6663)
>
> Fixes: 967176179215 ("drm/amd/display: fix null-pointer dereference on edid reading")
> Reported-by: Dan Carpenter <dan.carpenter at linaro.org>
> Signed-off-by: Melissa Wen <mwen at igalia.com>
> ---
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 32efce81a5a7..46dd06e8fc7e 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -6653,7 +6653,7 @@ static void amdgpu_dm_connector_funcs_force(struct drm_connector *connector)
>         struct edid *edid;
>         struct i2c_adapter *ddc;
>
> -       if (dc_link->aux_mode)
> +       if (dc_link && dc_link->aux_mode)
>                 ddc = &aconnector->dm_dp_aux.aux.ddc;
>         else
>                 ddc = &aconnector->i2c->base;
> --
> 2.43.0
>