[v4,02/12] selftests/harness: Merge TEST_F_FORK() into TEST_F()

Commit Message

Jakub Kicinski Feb. 29, 2024, 12:59 a.m. UTC

From: Mickaël Salaün <[e-mail]>

Replace Landlock-specific TEST_F_FORK() with an improved TEST_F() which
brings four related changes:

Run TEST_F()'s tests in a grandchild process to make it possible to
drop privileges and delegate teardown to the parent.

Compared to TEST_F_FORK(), simplify handling of the test grandchild
process thanks to vfork(2), and makes it generic (e.g. no explicit
conversion between exit code and _metadata).

Compared to TEST_F_FORK(), run teardown even when tests failed with an
assert thanks to commit 63e6b2a42342 ("selftests/harness: Run TEARDOWN
for ASSERT failures").

Simplify the test harness code by removing the no_print and step fields
which are not used.  I added this feature just after I made
kselftest_harness.h more broadly available but this step counter
remained even though it wasn't needed after all. See commit 369130b63178
("selftests: Enhance kselftest_harness.h to print which assert failed").

Replace spaces with tabs in one line of __TEST_F_IMPL().

Cc: Günther Noack <[e-mail]>
Cc: Shuah Khan <[e-mail]>
Cc: Will Drewry <[e-mail]>
Signed-off-by: Mickaël Salaün <[e-mail]>
Reviewed-by: Kees Cook <[e-mail]>
Signed-off-by: Jakub Kicinski <[e-mail]>
--
v4:
 - GAND -> GRAND
 - init child to 1, otherwise assert in setup triggers a longjmp
   which in turn reads child without it ever getting initialized
   (or being 0, i.e. we mistakenly assume we're in the grandchild)
---
 tools/testing/selftests/kselftest_harness.h | 56 +++++++++----------
 tools/testing/selftests/landlock/common.h   | 62 +--------------------
 2 files changed, 27 insertions(+), 91 deletions(-)

Comments

Mickaël Salaün March 4, 2024, 7:27 p.m. UTC | #1

Testing the whole series, I found that some Landlock tests are flaky
starting with this patch.  I tried to not use the longjmp in the
grandchild but it didn't change.  I suspect missing volatiles but I
didn't find the faulty one(s) yet. :/
I'll continue investigating tomorrow but help would be much appreciated!


On Wed, Feb 28, 2024 at 04:59:09PM -0800, Jakub Kicinski wrote:
> From: Mickaël Salaün <[e-mail]>
> 
> Replace Landlock-specific TEST_F_FORK() with an improved TEST_F() which
> brings four related changes:
> 
> Run TEST_F()'s tests in a grandchild process to make it possible to
> drop privileges and delegate teardown to the parent.
> 
> Compared to TEST_F_FORK(), simplify handling of the test grandchild
> process thanks to vfork(2), and makes it generic (e.g. no explicit
> conversion between exit code and _metadata).
> 
> Compared to TEST_F_FORK(), run teardown even when tests failed with an
> assert thanks to commit 63e6b2a42342 ("selftests/harness: Run TEARDOWN
> for ASSERT failures").
> 
> Simplify the test harness code by removing the no_print and step fields
> which are not used.  I added this feature just after I made
> kselftest_harness.h more broadly available but this step counter
> remained even though it wasn't needed after all. See commit 369130b63178
> ("selftests: Enhance kselftest_harness.h to print which assert failed").
> 
> Replace spaces with tabs in one line of __TEST_F_IMPL().
> 
> Cc: Günther Noack <[e-mail]>
> Cc: Shuah Khan <[e-mail]>
> Cc: Will Drewry <[e-mail]>
> Signed-off-by: Mickaël Salaün <[e-mail]>
> Reviewed-by: Kees Cook <[e-mail]>
> Signed-off-by: Jakub Kicinski <[e-mail]>
> --
> v4:
>  - GAND -> GRAND
>  - init child to 1, otherwise assert in setup triggers a longjmp
>    which in turn reads child without it ever getting initialized
>    (or being 0, i.e. we mistakenly assume we're in the grandchild)

Good catch!

Mickaël Salaün March 4, 2024, 7:31 p.m. UTC | #2

On Mon, Mar 04, 2024 at 08:27:50PM +0100, Mickaël Salaün wrote:
> Testing the whole series, I found that some Landlock tests are flaky
> starting with this patch.  I tried to not use the longjmp in the
> grandchild but it didn't change.  I suspect missing volatiles but I
> didn't find the faulty one(s) yet. :/
> I'll continue investigating tomorrow but help would be much appreciated!

The issue is with the fs_test.c, often starting with this one:

#  RUN           layout1.relative_chroot_only ...
# fs_test.c:294:relative_chroot_only:Expected 0 (0) == umount(TMP_DIR) (-1)
# fs_test.c:296:relative_chroot_only:Expected 0 (0) == remove_path(TMP_DIR) (16)
# relative_chroot_only: Test failed
#          FAIL  layout1.relative_chroot_only

...or this one:

#  RUN           layout3_fs.hostfs.tag_inode_dir_child ...
# fs_test.c:4707:tag_inode_dir_child:Expected 0 (0) == mkdir(self->dir_path, 0700) (-1)
# fs_test.c:4709:tag_inode_dir_child:Failed to create directory "tmp/dir": No such file or directory
# fs_test.c:4724:tag_inode_dir_child:Expected 0 (0) <= fd (-1)
# fs_test.c:4726:tag_inode_dir_child:Failed to create file "tmp/dir/file": No such file or directory
# fs_test.c:4729:tag_inode_dir_child:Expected 0 (0) == close(fd) (-1)
# tag_inode_dir_child: Test failed
#          FAIL  layout3_fs.hostfs.tag_inode_dir_child


> 
> 
> On Wed, Feb 28, 2024 at 04:59:09PM -0800, Jakub Kicinski wrote:
> > From: Mickaël Salaün <[e-mail]>
> > 
> > Replace Landlock-specific TEST_F_FORK() with an improved TEST_F() which
> > brings four related changes:
> > 
> > Run TEST_F()'s tests in a grandchild process to make it possible to
> > drop privileges and delegate teardown to the parent.
> > 
> > Compared to TEST_F_FORK(), simplify handling of the test grandchild
> > process thanks to vfork(2), and makes it generic (e.g. no explicit
> > conversion between exit code and _metadata).
> > 
> > Compared to TEST_F_FORK(), run teardown even when tests failed with an
> > assert thanks to commit 63e6b2a42342 ("selftests/harness: Run TEARDOWN
> > for ASSERT failures").
> > 
> > Simplify the test harness code by removing the no_print and step fields
> > which are not used.  I added this feature just after I made
> > kselftest_harness.h more broadly available but this step counter
> > remained even though it wasn't needed after all. See commit 369130b63178
> > ("selftests: Enhance kselftest_harness.h to print which assert failed").
> > 
> > Replace spaces with tabs in one line of __TEST_F_IMPL().
> > 
> > Cc: Günther Noack <[e-mail]>
> > Cc: Shuah Khan <[e-mail]>
> > Cc: Will Drewry <[e-mail]>
> > Signed-off-by: Mickaël Salaün <[e-mail]>
> > Reviewed-by: Kees Cook <[e-mail]>
> > Signed-off-by: Jakub Kicinski <[e-mail]>
> > --
> > v4:
> >  - GAND -> GRAND
> >  - init child to 1, otherwise assert in setup triggers a longjmp
> >    which in turn reads child without it ever getting initialized
> >    (or being 0, i.e. we mistakenly assume we're in the grandchild)
> 
> Good catch!

Mickaël Salaün March 5, 2024, 3:47 p.m. UTC | #3

I think I fixed all reported issues with the following patch.  It always
execute the fixture setup in the child process and execute the teardown
in the child process by default (e.g. for seccomp tests which have
assumptions about that). Only the Landlock teardown tests are executed
in the parent process thanks to the new _metadata->teardown_parent
boolean.  Child signals are always forwarded to the parent process where
__wait_for_test() check that.  This works with seccomp and Landlock
tests, and I think with all the others.  I'll send a v2 of the vfork
patch.

diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h
index ad49832457af..4f192904dfd6 100644
--- a/tools/testing/selftests/kselftest_harness.h
+++ b/tools/testing/selftests/kselftest_harness.h
@@ -382,29 +382,33 @@
 		/* fixture data is alloced, setup, and torn down per call. */ \
 		FIXTURE_DATA(fixture_name) self; \
 		pid_t child = 1; \
+		int status = 0; \
 		memset(&self, 0, sizeof(FIXTURE_DATA(fixture_name))); \
 		if (setjmp(_metadata->env) == 0) { \
-			fixture_name##_setup(_metadata, &self, variant->data); \
-			/* Let setup failure terminate early. */ \
-			if (!_metadata->passed || _metadata->skip) \
-				return; \
-			_metadata->setup_completed = true; \
 			/* Use the same _metadata. */ \
 			child = vfork(); \
 			if (child == 0) { \
+				fixture_name##_setup(_metadata, &self, variant->data); \
+				/* Let setup failure terminate early. */ \
+				if (!_metadata->passed || _metadata->skip) \
+					_exit(0); \
+				_metadata->setup_completed = true; \
 				fixture_name##_##test_name(_metadata, &self, variant->data); \
-				_exit(0); \
-			} \
-			if (child < 0) { \
+			} else if (child < 0 || child != waitpid(child, &status, 0)) { \
 				ksft_print_msg("ERROR SPAWNING TEST GRANDCHILD\n"); \
 				_metadata->passed = 0; \
 			} \
 		} \
-		if (child == 0) \
-			/* Child failed and updated the shared _metadata. */ \
+		if (child == 0) { \
+			if (_metadata->setup_completed && !_metadata->teardown_parent) \
+				fixture_name##_teardown(_metadata, &self, variant->data); \
 			_exit(0); \
-		if (_metadata->setup_completed) \
+		} \
+		if (_metadata->setup_completed && _metadata->teardown_parent) \
 			fixture_name##_teardown(_metadata, &self, variant->data); \
+		if (!WIFEXITED(status) && WIFSIGNALED(status)) \
+			/* Forward signal to __wait_for_test(). */ \
+			kill(getpid(), WTERMSIG(status)); \
 		__test_check_assert(_metadata); \
 	} \
 	static struct __test_metadata \
@@ -414,6 +418,7 @@
 		.fixture = &_##fixture_name##_fixture_object, \
 		.termsig = signal, \
 		.timeout = tmout, \
+		.teardown_parent = false, \
 	 }; \
 	static void __attribute__((constructor)) \
 			_register_##fixture_name##_##test_name(void) \
@@ -842,6 +847,7 @@ struct __test_metadata {
 	bool timed_out;	/* did this test timeout instead of exiting? */
 	bool aborted;	/* stopped test due to failed ASSERT */
 	bool setup_completed; /* did setup finish? */
+	bool teardown_parent; /* run teardown in a parent process */
 	jmp_buf env;	/* for exiting out of test early */
 	struct __test_results *results;
 	struct __test_metadata *prev, *next;
diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
index 2d6d9b43d958..1d5952897e05 100644
--- a/tools/testing/selftests/landlock/fs_test.c
+++ b/tools/testing/selftests/landlock/fs_test.c
@@ -285,6 +285,8 @@ static void prepare_layout_opt(struct __test_metadata *const _metadata,
 
 static void prepare_layout(struct __test_metadata *const _metadata)
 {
+	_metadata->teardown_parent = true;
+
 	prepare_layout_opt(_metadata, &mnt_tmp);
 }
 
@@ -3861,9 +3863,7 @@ FIXTURE_SETUP(layout1_bind)
 
 FIXTURE_TEARDOWN(layout1_bind)
 {
-	set_cap(_metadata, CAP_SYS_ADMIN);
-	EXPECT_EQ(0, umount(dir_s2d2));
-	clear_cap(_metadata, CAP_SYS_ADMIN);
+	/* umount(dir_s2d2)) is handled by namespace lifetime. */
 
 	remove_layout1(_metadata);
 
@@ -4276,9 +4276,8 @@ FIXTURE_TEARDOWN(layout2_overlay)
 	EXPECT_EQ(0, remove_path(lower_fl1));
 	EXPECT_EQ(0, remove_path(lower_do1_fo2));
 	EXPECT_EQ(0, remove_path(lower_fo1));
-	set_cap(_metadata, CAP_SYS_ADMIN);
-	EXPECT_EQ(0, umount(LOWER_BASE));
-	clear_cap(_metadata, CAP_SYS_ADMIN);
+
+	/* umount(LOWER_BASE)) is handled by namespace lifetime. */
 	EXPECT_EQ(0, remove_path(LOWER_BASE));
 
 	EXPECT_EQ(0, remove_path(upper_do1_fu3));
@@ -4287,14 +4286,11 @@ FIXTURE_TEARDOWN(layout2_overlay)
 	EXPECT_EQ(0, remove_path(upper_do1_fo2));
 	EXPECT_EQ(0, remove_path(upper_fo1));
 	EXPECT_EQ(0, remove_path(UPPER_WORK "/work"));
-	set_cap(_metadata, CAP_SYS_ADMIN);
-	EXPECT_EQ(0, umount(UPPER_BASE));
-	clear_cap(_metadata, CAP_SYS_ADMIN);
+
+	/* umount(UPPER_BASE)) is handled by namespace lifetime. */
 	EXPECT_EQ(0, remove_path(UPPER_BASE));
 
-	set_cap(_metadata, CAP_SYS_ADMIN);
-	EXPECT_EQ(0, umount(MERGE_DATA));
-	clear_cap(_metadata, CAP_SYS_ADMIN);
+	/* umount(MERGE_DATA)) is handled by namespace lifetime. */
 	EXPECT_EQ(0, remove_path(MERGE_DATA));
 
 	cleanup_layout(_metadata);
@@ -4691,6 +4687,8 @@ FIXTURE_SETUP(layout3_fs)
 		SKIP(return, "this filesystem is not supported (setup)");
 	}
 
+	_metadata->teardown_parent = true;
+
 	slash = strrchr(variant->file_path, '/');
 	ASSERT_NE(slash, NULL);
 	dir_len = (size_t)slash - (size_t)variant->file_path;


On Mon, Mar 04, 2024 at 08:31:49PM +0100, Mickaël Salaün wrote:
> On Mon, Mar 04, 2024 at 08:27:50PM +0100, Mickaël Salaün wrote:
> > Testing the whole series, I found that some Landlock tests are flaky
> > starting with this patch.  I tried to not use the longjmp in the
> > grandchild but it didn't change.  I suspect missing volatiles but I
> > didn't find the faulty one(s) yet. :/
> > I'll continue investigating tomorrow but help would be much appreciated!
> 
> The issue is with the fs_test.c, often starting with this one:
> 
> #  RUN           layout1.relative_chroot_only ...
> # fs_test.c:294:relative_chroot_only:Expected 0 (0) == umount(TMP_DIR) (-1)
> # fs_test.c:296:relative_chroot_only:Expected 0 (0) == remove_path(TMP_DIR) (16)
> # relative_chroot_only: Test failed
> #          FAIL  layout1.relative_chroot_only
> 
> ...or this one:
> 
> #  RUN           layout3_fs.hostfs.tag_inode_dir_child ...
> # fs_test.c:4707:tag_inode_dir_child:Expected 0 (0) == mkdir(self->dir_path, 0700) (-1)
> # fs_test.c:4709:tag_inode_dir_child:Failed to create directory "tmp/dir": No such file or directory
> # fs_test.c:4724:tag_inode_dir_child:Expected 0 (0) <= fd (-1)
> # fs_test.c:4726:tag_inode_dir_child:Failed to create file "tmp/dir/file": No such file or directory
> # fs_test.c:4729:tag_inode_dir_child:Expected 0 (0) == close(fd) (-1)
> # tag_inode_dir_child: Test failed
> #          FAIL  layout3_fs.hostfs.tag_inode_dir_child
> 

This was because the vfork() wasn't followed by a wait().

> 
> > 
> > 
> > On Wed, Feb 28, 2024 at 04:59:09PM -0800, Jakub Kicinski wrote:
> > > From: Mickaël Salaün <[e-mail]>
> > > 
> > > Replace Landlock-specific TEST_F_FORK() with an improved TEST_F() which
> > > brings four related changes:
> > > 
> > > Run TEST_F()'s tests in a grandchild process to make it possible to
> > > drop privileges and delegate teardown to the parent.
> > > 
> > > Compared to TEST_F_FORK(), simplify handling of the test grandchild
> > > process thanks to vfork(2), and makes it generic (e.g. no explicit
> > > conversion between exit code and _metadata).
> > > 
> > > Compared to TEST_F_FORK(), run teardown even when tests failed with an
> > > assert thanks to commit 63e6b2a42342 ("selftests/harness: Run TEARDOWN
> > > for ASSERT failures").
> > > 
> > > Simplify the test harness code by removing the no_print and step fields
> > > which are not used.  I added this feature just after I made
> > > kselftest_harness.h more broadly available but this step counter
> > > remained even though it wasn't needed after all. See commit 369130b63178
> > > ("selftests: Enhance kselftest_harness.h to print which assert failed").
> > > 
> > > Replace spaces with tabs in one line of __TEST_F_IMPL().
> > > 
> > > Cc: Günther Noack <[e-mail]>
> > > Cc: Shuah Khan <[e-mail]>
> > > Cc: Will Drewry <[e-mail]>
> > > Signed-off-by: Mickaël Salaün <[e-mail]>
> > > Reviewed-by: Kees Cook <[e-mail]>
> > > Signed-off-by: Jakub Kicinski <[e-mail]>
> > > --
> > > v4:
> > >  - GAND -> GRAND
> > >  - init child to 1, otherwise assert in setup triggers a longjmp
> > >    which in turn reads child without it ever getting initialized
> > >    (or being 0, i.e. we mistakenly assume we're in the grandchild)
> > 
> > Good catch!

Mickaël Salaün March 5, 2024, 3:56 p.m. UTC | #4

Hi,

This is a long due cleanup to merge TEST_F_FORK() into TEST_F().

This second version includes Jakub's "child" default value fix, proper
signal handling (TEST_SIGNAL), and move fixture setup and teardown to
the grandchild process by default.

This also removes the step counter and simplify Landlock's test
teardowns by removing some umount calls.

See https://lore.kernel.org/r/[e-mail]

Regards,

Mickaël Salaün (2):
  selftests/landlock: Redefine TEST_F() as TEST_F_FORK()
  selftests/harness: Merge TEST_F_FORK() into TEST_F()

 tools/testing/selftests/kselftest_harness.h | 72 ++++++++++-----------
 tools/testing/selftests/landlock/common.h   | 58 +----------------
 tools/testing/selftests/landlock/fs_test.c  | 22 +++----
 3 files changed, 48 insertions(+), 104 deletions(-)


base-commit: 90d35da658da8cff0d4ecbb5113f5fac9d00eb72

Patch

diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h
index e05ac8261046..ad49832457af 100644
--- a/tools/testing/selftests/kselftest_harness.h
+++ b/tools/testing/selftests/kselftest_harness.h
@@ -95,14 +95,6 @@ 
  * E.g., #define TH_LOG_ENABLED 1
  *
  * If no definition is provided, logging is enabled by default.
- *
- * If there is no way to print an error message for the process running the
- * test (e.g. not allowed to write to stderr), it is still possible to get the
- * ASSERT_* number for which the test failed.  This behavior can be enabled by
- * writing `_metadata->no_print = true;` before the check sequence that is
- * unable to print.  When an error occur, instead of printing an error message
- * and calling `abort(3)`, the test process call `_exit(2)` with the assert
- * number as argument, which is then printed by the parent process.
  */
 #define TH_LOG(fmt, ...) do { \
 	if (TH_LOG_ENABLED) \
@@ -363,6 +355,11 @@ 
  * Defines a test that depends on a fixture (e.g., is part of a test case).
  * Very similar to TEST() except that *self* is the setup instance of fixture's
  * datatype exposed for use by the implementation.
+ *
+ * The @test_name code is run in a separate process sharing the same memory
+ * (i.e. vfork), which means that the test process can update its privileges
+ * without impacting the related FIXTURE_TEARDOWN() (e.g. to remove files from
+ * a directory where write access was dropped).
  */
 #define TEST_F(fixture_name, test_name) \
 	__TEST_F_IMPL(fixture_name, test_name, -1, TEST_TIMEOUT_DEFAULT)
@@ -384,15 +381,28 @@ 
 	{ \
 		/* fixture data is alloced, setup, and torn down per call. */ \
 		FIXTURE_DATA(fixture_name) self; \
+		pid_t child = 1; \
 		memset(&self, 0, sizeof(FIXTURE_DATA(fixture_name))); \
 		if (setjmp(_metadata->env) == 0) { \
 			fixture_name##_setup(_metadata, &self, variant->data); \
 			/* Let setup failure terminate early. */ \
-                       if (!_metadata->passed || _metadata->skip) \
+			if (!_metadata->passed || _metadata->skip) \
 				return; \
 			_metadata->setup_completed = true; \
-			fixture_name##_##test_name(_metadata, &self, variant->data); \
+			/* Use the same _metadata. */ \
+			child = vfork(); \
+			if (child == 0) { \
+				fixture_name##_##test_name(_metadata, &self, variant->data); \
+				_exit(0); \
+			} \
+			if (child < 0) { \
+				ksft_print_msg("ERROR SPAWNING TEST GRANDCHILD\n"); \
+				_metadata->passed = 0; \
+			} \
 		} \
+		if (child == 0) \
+			/* Child failed and updated the shared _metadata. */ \
+			_exit(0); \
 		if (_metadata->setup_completed) \
 			fixture_name##_teardown(_metadata, &self, variant->data); \
 		__test_check_assert(_metadata); \
@@ -694,18 +704,12 @@ 
 	for (; _metadata->trigger; _metadata->trigger = \
 			__bail(_assert, _metadata))
 
-#define __INC_STEP(_metadata) \
-	/* Keep "step" below 255 (which is used for "SKIP" reporting). */	\
-	if (_metadata->passed && _metadata->step < 253) \
-		_metadata->step++;
-
 #define is_signed_type(var)       (!!(((__typeof__(var))(-1)) < (__typeof__(var))1))
 
 #define __EXPECT(_expected, _expected_str, _seen, _seen_str, _t, _assert) do { \
 	/* Avoid multiple evaluation of the cases */ \
 	__typeof__(_expected) __exp = (_expected); \
 	__typeof__(_seen) __seen = (_seen); \
-	if (_assert) __INC_STEP(_metadata); \
 	if (!(__exp _t __seen)) { \
 		/* Report with actual signedness to avoid weird output. */ \
 		switch (is_signed_type(__exp) * 2 + is_signed_type(__seen)) { \
@@ -751,7 +755,6 @@ 
 #define __EXPECT_STR(_expected, _seen, _t, _assert) do { \
 	const char *__exp = (_expected); \
 	const char *__seen = (_seen); \
-	if (_assert) __INC_STEP(_metadata); \
 	if (!(strcmp(__exp, __seen) _t 0))  { \
 		__TH_LOG("Expected '%s' %s '%s'.", __exp, #_t, __seen); \
 		_metadata->passed = 0; \
@@ -837,8 +840,6 @@  struct __test_metadata {
 	int trigger; /* extra handler after the evaluation */
 	int timeout;	/* seconds to wait for test timeout */
 	bool timed_out;	/* did this test timeout instead of exiting? */
-	__u8 step;
-	bool no_print; /* manual trigger when TH_LOG_STREAM is not available */
 	bool aborted;	/* stopped test due to failed ASSERT */
 	bool setup_completed; /* did setup finish? */
 	jmp_buf env;	/* for exiting out of test early */
@@ -873,11 +874,8 @@  static inline int __bail(int for_realz, struct __test_metadata *t)
 
 static inline void __test_check_assert(struct __test_metadata *t)
 {
-	if (t->aborted) {
-		if (t->no_print)
-			_exit(t->step);
+	if (t->aborted)
 		abort();
-	}
 }
 
 struct __test_metadata *__active_test;
@@ -954,13 +952,12 @@  void __wait_for_test(struct __test_metadata *t)
 			case 0:
 				t->passed = 1;
 				break;
-			/* Other failure, assume step report. */
+			/* Failure */
 			default:
 				t->passed = 0;
 				fprintf(TH_LOG_STREAM,
-					"# %s: Test failed at step #%d\n",
-					t->name,
-					WEXITSTATUS(status));
+					"# %s: Test failed\n",
+					t->name);
 			}
 		}
 	} else if (WIFSIGNALED(status)) {
@@ -1114,8 +1111,6 @@  void __run_test(struct __fixture_metadata *f,
 	t->passed = 1;
 	t->skip = 0;
 	t->trigger = 0;
-	t->step = 1;
-	t->no_print = 0;
 	memset(t->results->reason, 0, sizeof(t->results->reason));
 
 	ksft_print_msg(" RUN           %s%s%s.%s ...\n",
@@ -1137,8 +1132,7 @@  void __run_test(struct __fixture_metadata *f,
 		/* Pass is exit 0 */
 		if (t->passed)
 			_exit(0);
-		/* Something else happened, report the step. */
-		_exit(t->step);
+		_exit(1);
 	} else {
 		__wait_for_test(t);
 	}
diff --git a/tools/testing/selftests/landlock/common.h b/tools/testing/selftests/landlock/common.h
index f40146d40763..401e2eb092a3 100644
--- a/tools/testing/selftests/landlock/common.h
+++ b/tools/testing/selftests/landlock/common.h
@@ -23,66 +23,8 @@ 
 #define __maybe_unused __attribute__((__unused__))
 #endif
 
-/*
- * TEST_F_FORK() is useful when a test drop privileges but the corresponding
- * FIXTURE_TEARDOWN() requires them (e.g. to remove files from a directory
- * where write actions are denied).  For convenience, FIXTURE_TEARDOWN() is
- * also called when the test failed, but not when FIXTURE_SETUP() failed.  For
- * this to be possible, we must not call abort() but instead exit smoothly
- * (hence the step print).
- */
-/* clang-format off */
-#define TEST_F_FORK(fixture_name, test_name) \
-	static void fixture_name##_##test_name##_child( \
-		struct __test_metadata *_metadata, \
-		FIXTURE_DATA(fixture_name) *self, \
-		const FIXTURE_VARIANT(fixture_name) *variant); \
-	__TEST_F_IMPL(fixture_name, test_name, -1, TEST_TIMEOUT_DEFAULT) \
-	{ \
-		int status; \
-		const pid_t child = fork(); \
-		if (child < 0) \
-			abort(); \
-		if (child == 0) { \
-			_metadata->no_print = 1; \
-			fixture_name##_##test_name##_child(_metadata, self, variant); \
-			if (_metadata->skip) \
-				_exit(255); \
-			if (_metadata->passed) \
-				_exit(0); \
-			_exit(_metadata->step); \
-		} \
-		if (child != waitpid(child, &status, 0)) \
-			abort(); \
-		if (WIFSIGNALED(status) || !WIFEXITED(status)) { \
-			_metadata->passed = 0; \
-			_metadata->step = 1; \
-			return; \
-		} \
-		switch (WEXITSTATUS(status)) { \
-		case 0: \
-			_metadata->passed = 1; \
-			break; \
-		case 255: \
-			_metadata->passed = 1; \
-			_metadata->skip = 1; \
-			break; \
-		default: \
-			_metadata->passed = 0; \
-			_metadata->step = WEXITSTATUS(status); \
-			break; \
-		} \
-	} \
-	static void fixture_name##_##test_name##_child( \
-		struct __test_metadata __attribute__((unused)) *_metadata, \
-		FIXTURE_DATA(fixture_name) __attribute__((unused)) *self, \
-		const FIXTURE_VARIANT(fixture_name) \
-			__attribute__((unused)) *variant)
-/* clang-format on */
-
-/* Makes backporting easier. */
-#undef TEST_F
-#define TEST_F(fixture_name, test_name) TEST_F_FORK(fixture_name, test_name)
+/* TEST_F_FORK() should not be used for new tests. */
+#define TEST_F_FORK(fixture_name, test_name) TEST_F(fixture_name, test_name)
 
 #ifndef landlock_create_ruleset
 static inline int