Re: [PATCH 2/2] selftest/futex: Reintroduce "Memory out of range" numa_mpol's subtest

[Waiman Long <llong@redhat.com>]

On 9/1/25 4:33 PM, André Almeida wrote:
> Commit d8e2f919997 ("selftests/futex: Fix some futex_numa_mpol
> subtests") removed the "Memory out of range" subtest due to it being
> dependent on the memory layout of the test process having an invalid
> memory address just after the `*futex_ptr` allocated memory.
>
> Reintroduce this test and make it deterministic, by allocation two
> memory pages and marking the second one with PROT_NONE.
>
> Signed-off-by: André Almeida <andrealmeid@igalia.com>
> ---
> This patch is aimed for 6.18
> ---
>   .../testing/selftests/futex/functional/futex_numa_mpol.c  | 8 +++++++-
>   1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/futex/functional/futex_numa_mpol.c b/tools/testing/selftests/futex/functional/futex_numa_mpol.c
> index c84441751235..e4b840184b1d 100644
> --- a/tools/testing/selftests/futex/functional/futex_numa_mpol.c
> +++ b/tools/testing/selftests/futex/functional/futex_numa_mpol.c
> @@ -174,10 +174,13 @@ int main(int argc, char *argv[])
>   	ksft_set_plan(1);
>   
>   	mem_size = sysconf(_SC_PAGE_SIZE);
> -	futex_ptr = mmap(NULL, mem_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
> +	futex_ptr = mmap(NULL, mem_size * 2, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
>   	if (futex_ptr == MAP_FAILED)
>   		ksft_exit_fail_msg("mmap() for %d bytes failed\n", mem_size);
>   
> +	/* Create an invalid memory region for the "Memory out of range" test */
> +	mprotect(futex_ptr + mem_size, mem_size, PROT_NONE);
> +
>   	futex_numa = futex_ptr;
>   
>   	ksft_print_msg("Regular test\n");
> @@ -192,6 +195,9 @@ int main(int argc, char *argv[])
>   	ksft_print_msg("Mis-aligned futex\n");
>   	test_futex(futex_ptr + mem_size - 4, 22);
>   
> +	ksft_print_msg("Memory out of range\n");
> +	test_futex(futex_ptr + mem_size, 14);
> +
>   	futex_numa->numa = FUTEX_NO_NODE;
>   	mprotect(futex_ptr, mem_size, PROT_READ);
>   	ksft_print_msg("Memory, RO\n");
Reviewed-by: Waiman Long <longman@redhat.com>