Re: [PATCH] selftests/mm/cow: Modify the incorrect checking parameters

[Anshuman Khandual]

Hello Hao,

On 1/13/25 08:58, Hao Ge wrote:
> From: Hao Ge <gehao@xxxxxxxxxx>
> 
> In the run_with_memfd_hugetlb function, some error handle
> have passed incorrect parameters.
> It should be "smem", but it was mistakenly written as "mem".

I guess there are couple of more instances where the returned address
'smem' is not getting tested for MAP_FAILED. Hence the commit message
here needs to be bit more generic rather than run_with_memfd_hugetlb()
specific.

--- a/tools/testing/selftests/mm/cow.c
+++ b/tools/testing/selftests/mm/cow.c
@@ -1482,7 +1482,7 @@ static void run_with_zeropage(non_anon_test_fn fn, const char *desc)
        }
 
        smem = mmap(NULL, pagesize, PROT_READ, MAP_PRIVATE | MAP_ANON, -1, 0);
-       if (mem == MAP_FAILED) {
+       if (smem == MAP_FAILED) {
                ksft_test_result_fail("mmap() failed\n");
                goto munmap;
        }
@@ -1583,7 +1583,7 @@ static void run_with_memfd(non_anon_test_fn fn, const char *desc)
                goto close;
        }
        smem = mmap(NULL, pagesize, PROT_READ, MAP_SHARED, fd, 0);
-       if (mem == MAP_FAILED) {
+       if (smem == MAP_FAILED) {
                ksft_test_result_fail("mmap() failed\n");
                goto munmap;
        }


> 
> Let's fix it.
> 
> Fixes: baa489fabd01 ("selftests/vm: rename selftests/vm to selftests/mm")

This commit just renamed the directory from vm/ to mm/ directory. The following
commit introduced the problem instead. Please update the Fixes: tag as required.

f8664f3c4a08f799 ("selftests/vm: cow: basic COW tests for non-anonymous pages")

> Signed-off-by: Hao Ge <gehao@xxxxxxxxxx>
> ---
>  tools/testing/selftests/mm/cow.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/cow.c
> index 32c6ccc2a6be..7a89680d1566 100644
> --- a/tools/testing/selftests/mm/cow.c
> +++ b/tools/testing/selftests/mm/cow.c
> @@ -1684,7 +1684,7 @@ static void run_with_memfd_hugetlb(non_anon_test_fn fn, const char *desc,
>  		goto close;
>  	}
>  	smem = mmap(NULL, hugetlbsize, PROT_READ, MAP_SHARED, fd, 0);
> -	if (mem == MAP_FAILED) {
> +	if (smem == MAP_FAILED) {
>  		ksft_test_result_fail("mmap() failed\n");
>  		goto munmap;
>  	}
> @@ -1696,7 +1696,7 @@ static void run_with_memfd_hugetlb(non_anon_test_fn fn, const char *desc,
>  	fn(mem, smem, hugetlbsize);
>  munmap:
>  	munmap(mem, hugetlbsize);
> -	if (mem != MAP_FAILED)
> +	if (smem != MAP_FAILED)
>  		munmap(smem, hugetlbsize);
>  close:
>  	close(fd);