[PATCH 2/2] drm/amd/display: Fix null pointer dereference in error message

[Harry Wentland]

On 2023-09-27 10:07, Harry Wentland wrote:
> 
> 
> On 2023-09-27 01:23, Christian König wrote:
>> Am 26.09.23 um 15:09 schrieb Harry Wentland:
>>>
>>> On 2023-09-26 01:56, Cong Liu wrote:
>>>> This patch fixes a null pointer dereference in the error message that is
>>>> printed when the Display Core (DC) fails to initialize. The original
>>>> message includes the DC version number, which is undefined if the DC is
>>>> not initialized.
>>>>
>>>> Fixes: 9788d087caff ("drm/amd/display: improve the message printed when loading DC")
>>>> Signed-off-by: Cong Liu <liucong2 at kylinos.cn>
>>>> ---
>>>>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 +--
>>>>   1 file changed, 1 insertion(+), 2 deletions(-)
>>>>
>>>> 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 8e98dda1e084..bf52a909f558 100644
>>>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>>>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>>>> @@ -1703,8 +1703,7 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
>>>>           DRM_INFO("Display Core v%s initialized on %s\n", DC_VER,
>>>>                dce_version_to_string(adev->dm.dc->ctx->dce_version));
>>>>       } else {
>>>> -        DRM_INFO("Display Core v%s failed to initialize on %s\n", DC_VER,
>>>> -             dce_version_to_string(adev->dm.dc->ctx->dce_version));
>>>> +        DRM_INFO("Display Core failed to initialize with v%s!\n", DC_VER);
>>> There is value in printing the version number. Let's not remove it.
>>>
>>> Instead you can probably fix it by doing a NULL check on adev->dm.dc->ctx.
>>
>> But as far as I understand it adev->dm.dc->ctx will always be NULL in this case.
>>
> 
> Thanks, Christian. We're in the else of the NULL check for
> adev-dm.dc, so obviously we can't get the version. Silly me.
> 
> Your patch is
> Reviewed-by: Harry Wentland <harry.wentland at amd.com>
> 

Patch is merged.

Harry

> Harry
> 
>> Regards,
>> Christian.
>>
>>>
>>> Harry
>>>
>>>>           goto error;
>>>>       }
>>>>   
>>
>