Commit 4df9cefa authored by Peter Xu's avatar Peter Xu Committed by Andrew Morton
Browse files

selftests/mm: workaround no way to detect uffd-minor + wp 

Userfaultfd minor+wp mode was very recently added.  The test will fail on
the old kernels at ioctl(UFFDIO_CONTINUE) which is misterious. 
Unfortunately there's no feature bit to detect for this support.

Add a hack to leverage WP_UNPOPULATED to detect whether that feature
existed, since WP_UNPOPULATED was merged right after minor+wp.

Link: https://lkml.kernel.org/r/20230412164517.329152-1-peterx@redhat.com


Signed-off-by: default avatarPeter Xu <peterx@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent c3315502

tools/testing/selftests/mm/uffd-unit-tests.c

+7 −1
Original line number Diff line number Diff line
@@ -780,7 +780,13 @@ uffd_test_case_t uffd_tests[] = { 
		.mem_targets = MEM_SHMEM | MEM_HUGETLB,

		.uffd_feature_required =

		UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM |

		UFFD_FEATURE_PAGEFAULT_FLAG_WP,

		UFFD_FEATURE_PAGEFAULT_FLAG_WP |

		/*

		 * HACK: here we leveraged WP_UNPOPULATED to detect whether

		 * minor mode supports wr-protect.  There's no feature flag

		 * for it so this is the best we can test against.

		 */

		UFFD_FEATURE_WP_UNPOPULATED,

	},

	{

		.name = "minor-collapse",