linux-kernel - [PATCH v3 3/3] Turn off test_uffdio_wp if CONFIG_PTE_MARKER_UFFD

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Date: Wed, 26 Jun 2024 09:05:13 -0400
From: Audra Mitchell <audra@...hat.com>
To: viro@...iv.linux.org.uk
Cc: brauner@...nel.org,
	jack@...e.cz,
	aarcange@...hat.com,
	akpm@...ux-foundation.org,
	rppt@...ux.vnet.ibm.com,
	shli@...com,
	peterx@...hat.com,
	linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	shuah@...nel.org,
	linux-kselftest@...r.kernel.org,
	raquini@...hat.com,
	linux-mm@...ck.org
Subject: [PATCH v3 3/3] Turn off test_uffdio_wp if CONFIG_PTE_MARKER_UFFD_WP is not configured.

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.

Signed-off-by: Audra Mitchell <audra@...hat.com>
---
 tools/testing/selftests/mm/uffd-stress.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c
index b9b6d858eab8..3266ae885f75 100644
--- a/tools/testing/selftests/mm/uffd-stress.c
+++ b/tools/testing/selftests/mm/uffd-stress.c
@@ -419,6 +419,9 @@ static void parse_test_type_arg(const char *raw_type)
 	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;
 }
-- 
2.44.0