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From: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= <mic@digikod.net>
To: Christian Brauner <brauner@kernel.org>,
	Jakub Kicinski <kuba@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Mark Brown <broonie@kernel.org>,
	Shengyu Li <shengyu.li.evgeny@gmail.com>,
	Shuah Khan <shuah@kernel.org>
Cc: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= <mic@digikod.net>,
	"David S . Miller" <davem@davemloft.net>,
	=?UTF-8?q?G=C3=BCnther=20Noack?= <gnoack@google.com>,
	Will Drewry <wad@chromium.org>,
	kernel test robot <oliver.sang@intel.com>,
	linux-kernel@vger.kernel.org,
	linux-kselftest@vger.kernel.org,
	Shuah Khan <skhan@linuxfoundation.org>
Subject: [PATCH v2 8/9] selftests/harness: Share _metadata between forked processes
Date: Mon, 29 Apr 2024 15:09:30 +0200
Message-ID: <20240429130931.2394118-9-mic@digikod.net>
In-Reply-To: <20240429130931.2394118-1-mic@digikod.net>
References: <20240429130931.2394118-1-mic@digikod.net>
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Unconditionally share _metadata between all forked processes, which
enables to actually catch errors which were previously ignored.

This is required for a following commit replacing vfork() with clone3()
and CLONE_VFORK (i.e. not sharing the full memory) .  It should also be
useful to share _metadata to extend expectations to test process's
forks.  For instance, this change identified a wrong expectation in
pidfd_setns_test.

Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Will Drewry <wad@chromium.org>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20240429130931.2394118-9-mic@digikod.net
---

Changes since v1:
* Extract change from a bigger patch (suggested by Kees).
---
 tools/testing/selftests/kselftest_harness.h | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h
index 8a7d899a75e0..eceedb0a3586 100644
--- a/tools/testing/selftests/kselftest_harness.h
+++ b/tools/testing/selftests/kselftest_harness.h
@@ -430,19 +430,17 @@ static pid_t __attribute__((__unused__)) clone3_vfork(void)
 			kill(getpid(), WTERMSIG(status)); \
 		__test_check_assert(_metadata); \
 	} \
-	static struct __test_metadata \
-		      _##fixture_name##_##test_name##_object = { \
-		.name = #test_name, \
-		.fn = &wrapper_##fixture_name##_##test_name, \
-		.fixture = &_##fixture_name##_fixture_object, \
-		.termsig = signal, \
-		.timeout = tmout, \
-		.teardown_parent = false, \
-	 }; \
 	static void __attribute__((constructor)) \
 			_register_##fixture_name##_##test_name(void) \
 	{ \
-		__register_test(&_##fixture_name##_##test_name##_object); \
+		struct __test_metadata *object = mmap(NULL, sizeof(*object), \
+			PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); \
+		object->name = #test_name; \
+		object->fn = &wrapper_##fixture_name##_##test_name; \
+		object->fixture = &_##fixture_name##_fixture_object; \
+		object->termsig = signal; \
+		object->timeout = tmout; \
+		__register_test(object); \
 	} \
 	static void fixture_name##_##test_name( \
 		struct __test_metadata __attribute__((unused)) *_metadata, \
-- 
2.44.0