[PATCH 1/1] drm/amdgpu: Don't clear memory when PTB BO is released

[Christian König]

Am 07.07.22 um 18:45 schrieb Philip Yang:
> MMU notifier callback unmap the svm range update page table may free the
> PTB BO, then amdgpu_fill_buffer zero BO memory could cause deadlock as
> kmalloc may trigger MMU notifier.

Uff that means the whole free BO code path can't allocate anything.

I don't think we can do that.

>
> amdgpu_vm_pt_clear setup PTB BO memory with initial value, and no
> sensitive data in page table that must be wiped out before releasing the
> memory. So don't clear the memory when PTB BO is released.
>
> Signed-off-by: Philip Yang <Philip.Yang at amd.com>

Reviewed-by: Christian König <christian.koenig at amd.com> for this change 
here, but in general we need to talk about that once more.

Regards,
Christian.

> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> index 8a7b0f6162da..65b4ff6979ee 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> @@ -576,7 +576,7 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
>   	if (!amdgpu_bo_support_uswc(bo->flags))
>   		bo->flags &= ~AMDGPU_GEM_CREATE_CPU_GTT_USWC;
>   
> -	if (adev->ras_enabled)
> +	if (adev->ras_enabled && bp->type != ttm_bo_type_kernel)
>   		bo->flags |= AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE;
>   
>   	bo->tbo.bdev = &adev->mman.bdev;