Re: [PATCH] selftests/mm/ksm_functional: prevent unmapping undefined address

[David Hildenbrand <david@redhat.com>]

On 05.01.24 21:24, JP Kobryn wrote:
> Replace some goto statements with return statements so that unmap() is
> not called on an undefined address. This change is made so that unmap()
> can only be reached after mmap() is called (and the address mentioned is
> defined). Returning MAP_FAILED seems acceptable since client code checks
> for this value.
> 
> Fixes: 42096aa24b82 ("selftest/mm: ksm_functional_tests: test in mmap_and_merge_range() if anything got merged")
> Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
> ---
>   tools/testing/selftests/mm/ksm_functional_tests.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c
> index fbff0dd09191..d615767e396b 100644
> --- a/tools/testing/selftests/mm/ksm_functional_tests.c
> +++ b/tools/testing/selftests/mm/ksm_functional_tests.c
> @@ -155,12 +155,12 @@ static char *mmap_and_merge_range(char val, unsigned long size, int prot,
>   	/* Stabilize accounting by disabling KSM completely. */
>   	if (ksm_unmerge()) {
>   		ksft_test_result_fail("Disabling (unmerging) KSM failed\n");
> -		goto unmap;
> +		return MAP_FAILED;
>   	}
>   
>   	if (get_my_merging_pages() > 0) {
>   		ksft_test_result_fail("Still pages merged\n");
> -		goto unmap;
> +		return MAP_FAILED;
>   	}
>   
>   	map = mmap(NULL, size, PROT_READ|PROT_WRITE,

Indeed, thanks.

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Cheers,

David / dhildenb