Re: [PATCH v2] selftests/mm: Fix memleak in migration benchmark

[Balbir Singh <balbirs@nvidia.com>]

On 7/9/26 6:18 PM, Hongfu Li wrote:
> Several early return paths in run_migration_benchmark() skip
> hmm_buffer_free(), leaking the buffer. Replace with a single cleanup
> label.
> 
> Fixes: 271a7b2e3c13 ("selftests/mm/hmm-tests: new throughput tests including THP")
> Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
> Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
> Reviewed-by: SJ Park <sj@kernel.org>
> ---
> v2:
>  - Set buffer->ptr to NULL on mmap failure to avoid passing MAP_FAILED
>    to munmap() in hmm_buffer_free()
>  - Drop the redundant "/* Cleanup */" comment
>  - Add Fixes tag for the commit that introduced the leak
>  - Collect Reviewed-by tags from David Hildenbrand and SJ Park
> ---
>  tools/testing/selftests/mm/hmm-tests.c | 21 ++++++++++++---------
>  1 file changed, 12 insertions(+), 9 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/hmm-tests.c b/tools/testing/selftests/mm/hmm-tests.c
> index e4c49699f3f7..402c6f6f5f09 100644
> --- a/tools/testing/selftests/mm/hmm-tests.c
> +++ b/tools/testing/selftests/mm/hmm-tests.c
> @@ -2828,8 +2828,11 @@ static inline int run_migration_benchmark(int fd, int use_thp, size_t buffer_siz
>  	buffer->ptr = mmap(NULL, buffer_size, PROT_READ | PROT_WRITE,
>  			  MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
>  
> -	if (buffer->ptr == MAP_FAILED)
> -		return -1;
> +	if (buffer->ptr == MAP_FAILED) {
> +		buffer->ptr = NULL;
> +		ret = -1;
> +		goto cleanup;
> +	}
>  
>  	/* Apply THP hint if requested */
>  	if (use_thp)
> @@ -2838,7 +2841,7 @@ static inline int run_migration_benchmark(int fd, int use_thp, size_t buffer_siz
>  		ret = madvise(buffer->ptr, buffer_size, MADV_NOHUGEPAGE);
>  
>  	if (ret)
> -		return ret;
> +		goto cleanup;
>  
>  	/* Initialize memory to make sure pages are allocated */
>  	ptr = (int *)buffer->ptr;
> @@ -2848,11 +2851,11 @@ static inline int run_migration_benchmark(int fd, int use_thp, size_t buffer_siz
>  	/* Warmup iteration */
>  	ret = hmm_migrate_sys_to_dev(fd, buffer, npages);
>  	if (ret)
> -		return ret;
> +		goto cleanup;
>  
>  	ret = hmm_migrate_dev_to_sys(fd, buffer, npages);
>  	if (ret)
> -		return ret;
> +		goto cleanup;
>  
>  	/* Benchmark iterations */
>  	for (i = 0; i < iterations; i++) {
> @@ -2861,7 +2864,7 @@ static inline int run_migration_benchmark(int fd, int use_thp, size_t buffer_siz
>  
>  		ret = hmm_migrate_sys_to_dev(fd, buffer, npages);
>  		if (ret)
> -			return ret;
> +			goto cleanup;
>  
>  		end = get_time_ms();
>  		s2d_total += (end - start);
> @@ -2871,7 +2874,7 @@ static inline int run_migration_benchmark(int fd, int use_thp, size_t buffer_siz
>  
>  		ret = hmm_migrate_dev_to_sys(fd, buffer, npages);
>  		if (ret)
> -			return ret;
> +			goto cleanup;
>  
>  		end = get_time_ms();
>  		d2s_total += (end - start);
> @@ -2885,9 +2888,9 @@ static inline int run_migration_benchmark(int fd, int use_thp, size_t buffer_siz
>  	results->throughput_d2s = (buffer_size / (1024.0 * 1024.0 * 1024.0)) /
>  				 (results->dev_to_sys_time / 1000.0);
>  
> -	/* Cleanup */
> +cleanup:
>  	hmm_buffer_free(buffer);
> -	return 0;
> +	return ret;
>  }
>  
>  /*

Thanks!

Reviewed-by: Balbir Singh <balbirs@nvidia.com>