[PATCH v2] drm/amd/amdkfd: Fix a resource leak in svm_range_validate_and_map()

[Felix Kuehling]

On 2024-05-01 16:38, 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 at amd.com>

Reviewed-by: Felix Kuehling <felix.kuehling at amd.com>


> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 9 +++++++--
>   1 file changed, 7 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..481cb958e165 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 +1696,12 @@ 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
> +		 * Overrride return value to TRY AGAIN only if prior returns
> +		 * were successful
> +		 */
> +		if (hmm_range && amdgpu_hmm_range_get_pages_done(hmm_range) && !r) {
>   			pr_debug("hmm update the range, need validate again\n");
>   			r = -EAGAIN;
>   		}