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

[Christian König]

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 <liuco...@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.

Regards,
Christian.


Harry

                goto error;
        }