[PATCH] amdgpu_dm_2027: Add pointer check

[PATCH] amdgpu_dm_2027: Add pointer check

[Denis Arefev]

Return value of a function 'dc_create_state' is
dereferenced at amdgpu_dm.c:2027 without checking for null

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Denis Arefev <arefev@swemel.ru>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 4 +++-
 1 file changed, 3 insertions(+), 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 0f7749e9424d..529483997154 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1960,7 +1960,9 @@ static int dm_resume(void *handle)
 	dc_release_state(dm_state->context);
 	dm_state->context = dc_create_state(dm->dc);
 	/* TODO: Remove dc_state->dccg, use dc->dccg directly. */
-	dc_resource_state_construct(dm->dc, dm_state->context);
+	if (dm_state->context) {
+		dc_resource_state_construct(dm->dc, dm_state->context);
+	}
 
 	/* Before powering on DC we need to re-initialize DMUB. */
 	r = dm_dmub_hw_init(adev);
-- 
2.25.1

Re: [PATCH] amdgpu_dm_2027: Add pointer check

[Harry Wentland]

The commit title should user the drm/amd/display prefix.
It might also be good to be more specific, like:
drm/amd/display: Check dc_resource_state_construct succeeded

On 11/11/22 02:14, Denis Arefev wrote:
> Return value of a function 'dc_create_state' is
> dereferenced at amdgpu_dm.c:2027 without checking for null
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 

Does this fix a test case? If so, please describe.

> Signed-off-by: Denis Arefev <arefev@swemel.ru>
> ---
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 4 +++-
>  1 file changed, 3 insertions(+), 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 0f7749e9424d..529483997154 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -1960,7 +1960,9 @@ static int dm_resume(void *handle)
>  	dc_release_state(dm_state->context);
>  	dm_state->context = dc_create_state(dm->dc);
>  	/* TODO: Remove dc_state->dccg, use dc->dccg directly. */
> -	dc_resource_state_construct(dm->dc, dm_state->context);
> +	if (dm_state->context) {
> +		dc_resource_state_construct(dm->dc, dm_state->context);
> +	}

I don't see how this won't leave the driver state in a
mess. Are you sure this isn't a fatal error?

Harry

>  
>  	/* Before powering on DC we need to re-initialize DMUB. */
>  	r = dm_dmub_hw_init(adev);