[PATCH] drm/amdgpu: add missing NULL check

[PATCH] drm/amdgpu: add missing NULL check

[Christian König]

bo->tbo.resource can easily be NULL here.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_object.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
index f3ee83cdf97e..d28e21baef16 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
@@ -252,7 +252,7 @@ static inline bool amdgpu_bo_in_cpu_visible_vram(struct amdgpu_bo *bo)
 	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
 	struct amdgpu_res_cursor cursor;
 
-	if (bo->tbo.resource->mem_type != TTM_PL_VRAM)
+	if (!bo->tbo.resource || bo->tbo.resource->mem_type != TTM_PL_VRAM)
 		return false;
 
 	amdgpu_res_first(bo->tbo.resource, 0, amdgpu_bo_size(bo), &cursor);
-- 
2.34.1

Re: [PATCH] drm/amdgpu: add missing NULL check

[Alex Deucher]

On Fri, Oct 6, 2023 at 9:07 AM Christian König
<ckoenig.leichtzumerken@gmail.com> wrote:
>
> bo->tbo.resource can easily be NULL here.
>
> Signed-off-by: Christian König <christian.koenig@amd.com>

Add a link to the bug report?  With that:
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_object.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
> index f3ee83cdf97e..d28e21baef16 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
> @@ -252,7 +252,7 @@ static inline bool amdgpu_bo_in_cpu_visible_vram(struct amdgpu_bo *bo)
>         struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
>         struct amdgpu_res_cursor cursor;
>
> -       if (bo->tbo.resource->mem_type != TTM_PL_VRAM)
> +       if (!bo->tbo.resource || bo->tbo.resource->mem_type != TTM_PL_VRAM)
>                 return false;
>
>         amdgpu_res_first(bo->tbo.resource, 0, amdgpu_bo_size(bo), &cursor);
> --
> 2.34.1
>

Re: [PATCH] drm/amdgpu: add missing NULL check

[Christian König]

Am 06.10.23 um 16:41 schrieb Alex Deucher:
> On Fri, Oct 6, 2023 at 9:07 AM Christian König
> <ckoenig.leichtzumerken@gmail.com> wrote:
>> bo->tbo.resource can easily be NULL here.
>>
>> Signed-off-by: Christian König <christian.koenig@amd.com>
> Add a link to the bug report?

Ah, crap. Forgotten to add the link before pushing that. But I've added 
a CC stable.

Apart from that I suspect that this doesn't fix the real issue here, it 
just mitigates the problem.

For some reason we can't allocate OA resources, but also doesn't fail 
and instead keep working with an empty BO.

Regards,
Christian.

> With that:
> Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.h | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
>> index f3ee83cdf97e..d28e21baef16 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
>> @@ -252,7 +252,7 @@ static inline bool amdgpu_bo_in_cpu_visible_vram(struct amdgpu_bo *bo)
>>          struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
>>          struct amdgpu_res_cursor cursor;
>>
>> -       if (bo->tbo.resource->mem_type != TTM_PL_VRAM)
>> +       if (!bo->tbo.resource || bo->tbo.resource->mem_type != TTM_PL_VRAM)
>>                  return false;
>>
>>          amdgpu_res_first(bo->tbo.resource, 0, amdgpu_bo_size(bo), &cursor);
>> --
>> 2.34.1
>>

Re: [PATCH] drm/amdgpu: add missing NULL check

[Samuel Pitoiset]

I can confirm this patch fixes the kernel crash I reported.

But as discussed with Christian, we should find the root cause.

On 10/6/23 14:11, Christian König wrote:
> bo->tbo.resource can easily be NULL here.
>
> Signed-off-by: Christian König <christian.koenig@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
> index f3ee83cdf97e..d28e21baef16 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
> @@ -252,7 +252,7 @@ static inline bool amdgpu_bo_in_cpu_visible_vram(struct amdgpu_bo *bo)
>   	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
>   	struct amdgpu_res_cursor cursor;
>   
> -	if (bo->tbo.resource->mem_type != TTM_PL_VRAM)
> +	if (!bo->tbo.resource || bo->tbo.resource->mem_type != TTM_PL_VRAM)
>   		return false;
>   
>   	amdgpu_res_first(bo->tbo.resource, 0, amdgpu_bo_size(bo), &cursor);