Re: [PATCH 1/5] drm/amdgpu: allow variable BO struct creation

[Christian König <ckoenig.leichtzumerken@xxxxxxxxx>]

Am 05.03.21 um 16:06 schrieb Nirmoy Das:
> Allow allocating BO structures with different structure size
> than struct amdgpu_bo.
>
> Signed-off-by: Nirmoy Das <nirmoy.das@xxxxxxx>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 10 +++++++++-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.h |  1 +
>   2 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> index 0bd22ed1dacf..1ff8c3570c82 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> @@ -551,8 +551,12 @@ static int amdgpu_bo_do_create(struct amdgpu_device *adev,
>   
>   	acc_size = ttm_bo_dma_acc_size(&adev->mman.bdev, size,
>   				       sizeof(struct amdgpu_bo));
> +	if (bp->bo_ptr_size < sizeof(struct amdgpu_bo)) {
> +		DRM_ERROR("can't create BO with size < struct amdgpu_bo\n");
> +		return -EINVAL;
> +	}

Please make this a BUG_ON instead. When this is wrong we corrupt kernel 
memory.

Christian.

>   
> -	bo = kzalloc(sizeof(struct amdgpu_bo), GFP_KERNEL);
> +	bo = kzalloc(bp->bo_ptr_size, GFP_KERNEL);
>   	if (bo == NULL)
>   		return -ENOMEM;
>   	drm_gem_private_object_init(adev_to_drm(adev), &bo->tbo.base, size);
> @@ -642,6 +646,7 @@ static int amdgpu_bo_create_shadow(struct amdgpu_device *adev,
>   		AMDGPU_GEM_CREATE_SHADOW;
>   	bp.type = ttm_bo_type_kernel;
>   	bp.resv = bo->tbo.base.resv;
> +	bp.bo_ptr_size = sizeof(struct amdgpu_bo);
>   
>   	r = amdgpu_bo_do_create(adev, &bp, &bo->shadow);
>   	if (!r) {
> @@ -676,6 +681,9 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
>   	int r;
>   
>   	bp->flags = bp->flags & ~AMDGPU_GEM_CREATE_SHADOW;
> +	if (bp->bo_ptr_size < sizeof(struct amdgpu_bo))
> +		bp->bo_ptr_size = sizeof(struct amdgpu_bo);
> +
>   	r = amdgpu_bo_do_create(adev, bp, bo_ptr);
>   	if (r)
>   		return r;
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
> index 8cd96c9330dd..848dc0a017dd 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
> @@ -40,6 +40,7 @@
>   struct amdgpu_bo_param {
>   	unsigned long			size;
>   	int				byte_align;
> +	u32				bo_ptr_size;
>   	u32				domain;
>   	u32				preferred_domain;
>   	u64				flags;

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