Re: [PATCH] drm/amd/amdkfd: Fix a resource leak in svm_range_validate_and_map()

[Philip Yang <yangp@xxxxxxx>]

On 2024-04-30 19:29, Ramesh Errabolu wrote:

> Analysis of code by Coverity, a static code analyser, has identified
> a resource leak in the symbol hmm_range. This leak occurs when one of
> the prior steps before it is released encounters an error.
>
> Signed-off-by: Ramesh Errabolu <Ramesh.Errabolu@xxxxxxx>
>     
    Reviewed-by: Philip Yang <Philip.Yang@xxxxxxx>
> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> index 386875e6eb96..dcb1d5d3f860 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> @@ -1658,7 +1658,7 @@ static int svm_range_validate_and_map(struct mm_struct *mm,
>  	start = map_start << PAGE_SHIFT;
>  	end = (map_last + 1) << PAGE_SHIFT;
>  	for (addr = start; !r && addr < end; ) {
> -		struct hmm_range *hmm_range;
> +		struct hmm_range *hmm_range = NULL;
>  		unsigned long map_start_vma;
>  		unsigned long map_last_vma;
>  		struct vm_area_struct *vma;
> @@ -1696,7 +1696,9 @@ static int svm_range_validate_and_map(struct mm_struct *mm,
>  		}
>  
>  		svm_range_lock(prange);
> -		if (!r && amdgpu_hmm_range_get_pages_done(hmm_range)) {
> +
> +		// Free backing memory of hmm_range if it was initialized
> +		if (hmm_range && amdgpu_hmm_range_get_pages_done(hmm_range)) {
>  			pr_debug("hmm update the range, need validate again\n");
>  			r = -EAGAIN;
>  		}
>