On 9/26/26 14:41, Donggeun Yoo wrote:
> Move a swapped-out page out of a write-protected or RWP-protected area into
> a destination registered for missing faults only, and read pagemap bit 57
> at the destination. The destination was never protected, so the bit must
> be clear.
>
> Assisted-by: LLM
> Signed-off-by: Donggeun Yoo <[email protected]>
> ---
> tools/testing/selftests/mm/uffd-unit-tests.c | 84 ++++++++++++++++++++
> 1 file changed, 84 insertions(+)
>
> diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c
> b/tools/testing/selftests/mm/uffd-unit-tests.c
> index ef9b3956bdcfd..580178630eded 100644
> --- a/tools/testing/selftests/mm/uffd-unit-tests.c
> +++ b/tools/testing/selftests/mm/uffd-unit-tests.c
> @@ -2037,6 +2037,75 @@ static void
> uffd_move_pmd_split_test(uffd_global_test_opts_t *gopts, uffd_test_a
> uffd_move_pmd_handle_fault);
> }
>
> +/*
> + * Moving a swapped-out page out of a write-protected or RWP-protected area
> + * must not carry the uffd bit into a destination registered for missing
> + * faults only: such a bit is never cleared afterwards, so pagemap keeps
> + * reporting the page as uffd-tracked.
> + *
> + * Needs a swap device; skipped if MADV_PAGEOUT cannot evict the page.
> + */
> +static void uffd_move_swap_test_common(uffd_global_test_opts_t *gopts,
> + bool rwp)
> +{
> + unsigned long page_size = gopts->page_size;
> + struct uffdio_move move = { };
> + int pagemap_fd;
> +
> + if (rwp) {
> + if (uffd_register_rwp(gopts->uffd, gopts->area_src, page_size))
> + err("register src failure");
> + } else if (uffd_register(gopts->uffd, gopts->area_src, page_size,
> + false, true, false)) {
> + err("register src failure");
> + }
if ()
> + if (uffd_register(gopts->uffd, gopts->area_dst, page_size,
> + true, false, false))
> + err("register dst failure");
> +
> + if (rwp)
> + rwprotect_range(gopts->uffd, (unsigned long)gopts->area_src,
> + page_size, true);
> + else
> + wp_range(gopts->uffd, (unsigned long)gopts->area_src,
> + page_size, true);
> +
> + pagemap_fd = pagemap_open();
> + if (madvise(gopts->area_src, page_size, MADV_PAGEOUT))
> + err("MADV_PAGEOUT");
> + if (!pagemap_is_swapped(pagemap_fd, gopts->area_src)) {
> + uffd_test_skip("MADV_PAGEOUT did not swap the page; is swap
> enabled?");
> + goto out;
> + }
> +
> + move.dst = (unsigned long)gopts->area_dst;
> + move.src = (unsigned long)gopts->area_src;
> + move.len = page_size;
> + if (ioctl(gopts->uffd, UFFDIO_MOVE, &move))
> + err("UFFDIO_MOVE");
> +
> + if (pagemap_get_entry(pagemap_fd, gopts->area_dst) & PM_UFFD_WP)
> + uffd_test_fail("uffd bit moved into an area registered for
> missing faults only");
> + else
> + uffd_test_pass();
> +out:
> + close(pagemap_fd);
> + uffd_unregister(gopts->uffd, gopts->area_src, page_size);
> + uffd_unregister(gopts->uffd, gopts->area_dst, page_size);
> +}
> +
> +static void uffd_move_swap_wp_test(uffd_global_test_opts_t *gopts,
> + uffd_test_args_t *targs)
> +{
> + uffd_move_swap_test_common(gopts, false);
> +}
> +
> +static void uffd_move_swap_rwp_test(uffd_global_test_opts_t *gopts,
> + uffd_test_args_t *targs)
> +{
> + uffd_move_swap_test_common(gopts, true);
> +}
> +
> static bool
> uffdio_verify_results(const char *name, int ret, int error, long result)
> {
> @@ -2359,6 +2428,21 @@ uffd_test_case_t uffd_tests[] = {
> .uffd_feature_required = UFFD_FEATURE_MOVE,
> .test_case_ops = &uffd_move_test_pmd_case_ops,
> },
> + {
> + .name = "move-swap-wp",
> + .uffd_fn = uffd_move_swap_wp_test,
> + .mem_targets = MEM_ANON,
> + .uffd_feature_required = UFFD_FEATURE_MOVE |
> + UFFD_FEATURE_PAGEFAULT_FLAG_WP,
> + .test_case_ops = &uffd_move_test_case_ops,
> + },
> + {
> + .name = "move-swap-rwp",
> + .uffd_fn = uffd_move_swap_rwp_test,
> + .mem_targets = MEM_ANON,
> + .uffd_feature_required = UFFD_FEATURE_MOVE | UFFD_FEATURE_RWP,
> + .test_case_ops = &uffd_move_test_case_ops,
> + },
> {
> .name = "wp-fork",
> .uffd_fn = uffd_wp_fork_test,
--
Cheers,
David
