[PATCH v7 1/7] selftests/mm/guard-regions: skip collapse test when thp not enabled

Chunyu Hu
2026-03-30T15:15:38Z

When thp is not available, just skip the collape tests to avoid the false
negative.

Without the change, run with a thp disabled kernel:
./run_vmtests.sh -t madv_guard -n 1
<snip/>
# RUN guard_regions.anon.collapse ...
# guard-regions.c:2217:collapse:Expected madvise(ptr, size, MADV_NOHUGEPAGE) (-1) == 0 (0)
# collapse: Test terminated by assertion
# FAIL guard_regions.anon.collapse
not ok 2 guard_regions.anon.collapse
<snip/>
# RUN guard_regions.shmem.collapse ...
# guard-regions.c:2217:collapse:Expected madvise(ptr, size, MADV_NOHUGEPAGE) (-1) == 0 (0)
# collapse: Test terminated by assertion
# FAIL guard_regions.shmem.collapse
not ok 32 guard_regions.shmem.collapse
<snip/>
# RUN guard_regions.file.collapse ...
# guard-regions.c:2217:collapse:Expected madvise(ptr, size, MADV_NOHUGEPAGE) (-1) == 0 (0)
# collapse: Test terminated by assertion
# FAIL guard_regions.file.collapse
not ok 62 guard_regions.file.collapse
<snip/>
# FAILED: 87 / 90 tests passed.
# 17 skipped test(s) detected. Consider enabling relevant config options to improve coverage.
# Totals: pass:70 fail:3 xfail:0 xpass:0 skip:17 error:0

With this change, run with thp disabled kernel:
./run_vmtests.sh -t madv_guard -n 1
<snip/>
# RUN guard_regions.anon.collapse ...
# SKIP Transparent Hugepages not available
# OK guard_regions.anon.collapse
ok 2 guard_regions.anon.collapse # SKIP Transparent Hugepages not available
<snip/>
# RUN guard_regions.file.collapse ...
# SKIP Transparent Hugepages not available
# OK guard_regions.file.collapse
ok 62 guard_regions.file.collapse # SKIP Transparent Hugepages not available
<snip/>
# RUN guard_regions.shmem.collapse ...
# SKIP Transparent Hugepages not available
# OK guard_regions.shmem.collapse
ok 32 guard_regions.shmem.collapse # SKIP Transparent Hugepages not available
<snip/>
# PASSED: 90 / 90 tests passed.
# 20 skipped test(s) detected. Consider enabling relevant config options to improve coverage.
# Totals: pass:70 fail:0 xfail:0 xpass:0 skip:20 error:0

Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
CC: Li Wang <liwang@redhat.com>
Signed-off-by: Chunyu Hu <chuhu@redhat.com>
---
Changes in v7:
- Add reviewed-by from Lorenzo
Changes in v5:
- updated reviewed-by and acked-by
Changes in v4:
- use thp_available instead of thp_is_enabled() as when thp is set to
never, madvise(MADV_COLLAPSE) will still succeed by design. So a
failure in madvise(MADV_COLLAPSE) on guard region will verify guard
region denies it. This is suggested from AI.
- removed the 'Reviewed-by' and 'Acked-by' as the code changes. Sorry for
that but it seems the changes is a little huge? (1 out of 2 lines)..
Changes in v3:
- commit message: update the log snippet with where the fail happens and
add the '-n1' to the command.
- fix the 'false positive' to 'false negative'
- add reviwed by from Mike
Changes in v2:
- add reviewed by from Zi and Lorenzo
- add acked-by from David
---
tools/testing/selftests/mm/guard-regions.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/tools/testing/selftests/mm/guard-regions.c b/tools/testing/selftests/mm/guard-regions.c
index dbd21d66d383..48e8b1539be3 100644
--- a/tools/testing/selftests/mm/guard-regions.c
+++ b/tools/testing/selftests/mm/guard-regions.c
@@ -21,6 +21,7 @@
#include <sys/uio.h>
#include <unistd.h>
#include "vm_util.h"
+#include "thp_settings.h"

#include "../pidfd/pidfd.h"

@@ -2195,6 +2196,9 @@ TEST_F(guard_regions, collapse)
char *ptr;
int i;

+ if (!thp_available())
+ SKIP(return, "Transparent Hugepages not available\n");
+
/* Need file to be correct size for tests for non-anon. */
if (variant->backing != ANON_BACKED)
ASSERT_EQ(ftruncate(self->fd, size), 0);

base-commit: 7aaa8047eafd0bd628065b15757d9b48c5f9c07d
--
2.53.0