Re: [PATCH v2] selftests/mm/mseal_test: Fix mmap return value check in test_seal_zero_address

[Andrew Morton]

On Tue,  7 Jul 2026 11:17:45 +0800 longlong yan <yanlonglong@xxxxxxxxxx> wrote:

> The return value for a failed mmap function is MAP_FAILED.
> According to the definition of FAIL_TEST_IF FALSE,ptr must be
> determined to be distinct from MAP_FAILED
> 
> ...
>
> --- a/tools/testing/selftests/mm/mseal_test.c
> +++ b/tools/testing/selftests/mm/mseal_test.c
> @@ -482,7 +482,7 @@ static void test_seal_zero_address(void)
>  	/* use mmap to change protection. */
>  	ptr = mmap(0, size, PROT_NONE,
>  		   MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
> -	FAIL_TEST_IF_FALSE(ptr == 0);
> +	FAIL_TEST_IF_FALSE(ptr != (void *)-1);
>  
>  	size = get_vma_size(ptr, &prot);
>  	FAIL_TEST_IF_FALSE(size == 4 * page_size);

Has this been tested?

AI review is suggesting the code was supposed to be this way and it
appears to have a point:
	https://sashiko.dev/#/patchset/20260707031745.1039-1-yanlonglong@xxxxxxxxxx