+ turn-off-test_uffdio_wp-if-config_pte_marker_uffd_wp-is-not-configured.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm: turn off test_uffdio_wp if CONFIG_PTE_MARKER_UFFD_WP is not configured.
has been added to the -mm mm-unstable branch.  Its filename is
     turn-off-test_uffdio_wp-if-config_pte_marker_uffd_wp-is-not-configured.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/turn-off-test_uffdio_wp-if-config_pte_marker_uffd_wp-is-not-configured.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Audra Mitchell <audra@redhat.com>
Subject: mm: turn off test_uffdio_wp if CONFIG_PTE_MARKER_UFFD_WP is not configured.
Date: Wed, 26 Jun 2024 09:05:13 -0400

If CONFIG_PTE_MARKER_UFFD_WP is disabled, then we turn off three features
in userfaultfd_api (UFFD_FEATURE_WP_HUGETLBFS_SHMEM,
UFFD_FEATURE_WP_UNPOPULATED, and UFFD_FEATURE_WP_ASYNC).

Currently this test always will call uffdio_regsiter with the flag
UFFDIO_REGISTER_MODE_WP.  However, the kernel ensures in vma_can_userfault
that if the feature UFFD_FEATURE_WP_HUGETLBFS_SHMEM is disabled, only
allow the VM_UFFD_WP on anonymous vmas, meaning our call to
uffdio_regsiter will fail.

We still want to be able to run the test even if we have
CONFIG_PTE_MARKER_UFFD_WP disabled, so check to see if the feature
UFFD_FEATURE_WP_HUGETLBFS_SHMEM has been turned off in the test and if so,
disable us from calling uffdio_regsiter with the flag
UFFDIO_REGISTER_MODE_WP.

Link: https://lkml.kernel.org/r/20240626130513.120193-3-audra@redhat.com
Signed-off-by: Audra Mitchell <audra@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/mm/uffd-stress.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/tools/testing/selftests/mm/uffd-stress.c~turn-off-test_uffdio_wp-if-config_pte_marker_uffd_wp-is-not-configured
+++ a/tools/testing/selftests/mm/uffd-stress.c
@@ -417,6 +417,9 @@ static void parse_test_type_arg(const ch
 	test_uffdio_wp = test_uffdio_wp &&
 		(features & UFFD_FEATURE_PAGEFAULT_FLAG_WP);
 
+	if (test_type != TEST_ANON && !(features & UFFD_FEATURE_WP_HUGETLBFS_SHMEM))
+		test_uffdio_wp = false;
+
 	close(uffd);
 	uffd = -1;
 }
_

Patches currently in -mm which might be from audra@redhat.com are

fix-userfaultfd_api-to-return-einval-as-expected.patch
update-uffd-stress-to-handle-einval-for-unset-config-features.patch
turn-off-test_uffdio_wp-if-config_pte_marker_uffd_wp-is-not-configured.patch