[PATCH 1/2] selftests/harness: order TEST_F and XFAIL_ADD constructors

[Sun Jian <sun.jian.kdev@gmail.com>]

TEST_F() allocates and registers its struct __test_metadata via mmap()
inside its constructor, and only then assigns the
_##fixture_##test##_object pointer.

XFAIL_ADD() runs in a constructor too and reads
_##fixture_##test##_object to initialize xfail->test. If XFAIL_ADD runs
first, xfail->test can be NULL and the expected failure will be reported
as FAIL.

Use constructor priorities to ensure TEST_F registration runs before
XFAIL_ADD, without adding extra state or runtime lookups.

Fixes: 2709473c9386 ("selftests: kselftest_harness: support using xfail")
Signed-off-by: Sun Jian <sun.jian.kdev@gmail.com>
---
v2:
  - Switch from name-based fallback matching to ctor priorities.
  - Drop the extra xfail state and runtime matching.
---
 tools/testing/selftests/kselftest_harness.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h
index 16a119a4656c..afcba0c4e98d 100644
--- a/tools/testing/selftests/kselftest_harness.h
+++ b/tools/testing/selftests/kselftest_harness.h
@@ -175,6 +175,9 @@ static inline void __kselftest_memset_safe(void *s, int c, size_t n)
  *
  * EXPECT_* and ASSERT_* are valid in a TEST() { } context.
  */
+#define KSELFTEST_PRIO_TEST_F  20000
+#define KSELFTEST_PRIO_XFAIL   20001
+
 #define TEST_SIGNAL(test_name, signal) __TEST_IMPL(test_name, signal)
 
 #define __TEST_IMPL(test_name, _signal) \
@@ -465,7 +468,7 @@ static inline void __kselftest_memset_safe(void *s, int c, size_t n)
 			fixture_name##_teardown(_metadata, self, variant); \
 	} \
 	static struct __test_metadata *_##fixture_name##_##test_name##_object; \
-	static void __attribute__((constructor)) \
+	static void __attribute__((constructor(KSELFTEST_PRIO_TEST_F))) \
 			_register_##fixture_name##_##test_name(void) \
 	{ \
 		struct __test_metadata *object = mmap(NULL, sizeof(*object), \
@@ -880,7 +883,7 @@ struct __test_xfail {
 		.fixture = &_##fixture_name##_fixture_object, \
 		.variant = &_##fixture_name##_##variant_name##_object, \
 	}; \
-	static void __attribute__((constructor)) \
+	static void __attribute__((constructor(KSELFTEST_PRIO_XFAIL))) \
 		_register_##fixture_name##_##variant_name##_##test_name##_xfail(void) \
 	{ \
 		_##fixture_name##_##variant_name##_##test_name##_xfail.test = \

base-commit: 7dff99b354601dd01829e1511711846e04340a69
-- 
2.43.0