Re: [PATCH] drm/amdkfd: Fix memory leak in kfd_mem_dmamap_userptr()

[Felix Kuehling]

On 2022-10-17 21:27, Rafael Mendonca wrote:
> If the number of pages from the userptr BO differs from the SG BO then the
> allocated memory for the SG table doesn't get freed before returning
> -EINVAL, which may lead to a memory leak in some error paths. Fix this by
> checking the number of pages before allocating memory for the SG table.
>
> Fixes: 264fb4d332f5 ("drm/amdgpu: Add multi-GPU DMA mapping helpers")
> Signed-off-by: Rafael Mendonca <rafaelmendsr@xxxxxxxxx>

Thank you for catching this. The patch is

Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>

I submitted it to our amd-staging-drm-next branch.

Regards,
  Felix


> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> index 978d3970b5cc..84f44f7e4111 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> @@ -510,13 +510,13 @@ kfd_mem_dmamap_userptr(struct kgd_mem *mem,
>   	struct ttm_tt *ttm = bo->tbo.ttm;
>   	int ret;
>   
> +	if (WARN_ON(ttm->num_pages != src_ttm->num_pages))
> +		return -EINVAL;
> +
>   	ttm->sg = kmalloc(sizeof(*ttm->sg), GFP_KERNEL);
>   	if (unlikely(!ttm->sg))
>   		return -ENOMEM;
>   
> -	if (WARN_ON(ttm->num_pages != src_ttm->num_pages))
> -		return -EINVAL;
> -
>   	/* Same sequence as in amdgpu_ttm_tt_pin_userptr */
>   	ret = sg_alloc_table_from_pages(ttm->sg, src_ttm->pages,
>   					ttm->num_pages, 0,