Merge tag 'linux-kselftest-4.13-rc1-update' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull Kselftest updates from Shuah Khan:
 "This update consists of:

   - TAP13 framework and changes to some tests to convert to TAP13.
     Converting kselftest output to standard format will help identify
     run to run differences and pin point failures easily. TAP13 format
     has been in use for several years and the output is human friendly.

     Please find the specification:
       https://testanything.org/tap-version-13-specification.html

     Credit goes to Tim Bird for recommending TAP13 as a suitable
     format, and to Grag KH for kick starting the work with help from
     Paul Elder and Alice Ferrazzi

     The first phase of the TAp13 conversion is included in this update.
     Future updates will include updates to rest of the tests.

   - Masami Hiramatsu fixed ftrace to run on 4.9 stable kernels.

   - Kselftest documnetation has been converted to ReST format. Document
     now has a new home under Documentation/dev-tools.

   - kselftest_harness.h is now available for general use as a result of
     Mickaël Salaün's work.

   - Several fixes to skip and/or fail tests gracefully on older
     releases"

* tag 'linux-kselftest-4.13-rc1-update' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (48 commits)
  selftests: membarrier: use ksft_* var arg msg api
  selftests: breakpoints: breakpoint_test_arm64: convert test to use TAP13
  selftests: breakpoints: step_after_suspend_test use ksft_* var arg msg api
  selftests: breakpoint_test: use ksft_* var arg msg api
  kselftest: add ksft_print_msg() function to output general information
  kselftest: make ksft_* output functions variadic
  selftests/capabilities: Fix the test_execve test
  selftests: intel_pstate: add .gitignore
  selftests: fix memory-hotplug test
  selftests: add missing test name in memory-hotplug test
  selftests: check percentage range for memory-hotplug test
  selftests: check hot-pluggagble memory for memory-hotplug test
  selftests: typo correction for memory-hotplug test
  selftests: ftrace: Use md5sum to take less time of checking logs
  tools/testing/selftests/sysctl: Add pre-check to the value of writes_strict
  kselftest.rst: do some adjustments after ReST conversion
  selftest/net/Makefile: Specify output with $(OUTPUT)
  selftest/intel_pstate/aperf: Use LDLIBS instead of LDFLAGS
  selftest/memfd/Makefile: Fix build error
  selftests: lib: Skip tests on missing test modules
  ...

42 files changed, 1011 insertions, 509 deletions

diff --git a/Documentation/00-INDEX b/Documentation/00-INDEX
index f35473f8c630..3bec49c33bbb 100644
--- a/Documentation/00-INDEX
+++ b/Documentation/00-INDEX
@@ -242,8 +242,6 @@ kprobes.txt
 	- documents the kernel probes debugging feature.
 kref.txt
 	- docs on adding reference counters (krefs) to kernel objects.
-kselftest.txt
-	- small unittests for (some) individual codepaths in the kernel.
 laptops/
 	- directory with laptop related info and laptop driver documentation.
 ldm.txt
diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/index.rst
index 4ac991dbddb7..a81787cd47d7 100644
--- a/Documentation/dev-tools/index.rst
+++ b/Documentation/dev-tools/index.rst
@@ -24,6 +24,7 @@ whole; patches welcome!
    kmemcheck
    gdb-kernel-debugging
    kgdb
+   kselftest
 
 
 .. only::  subproject and html
diff --git a/Documentation/kselftest.txt b/Documentation/dev-tools/kselftest.rst
index 5bd590335839..ebd03d11d2c2 100644
--- a/Documentation/kselftest.txt
+++ b/Documentation/dev-tools/kselftest.rst
@@ -1,4 +1,6 @@
+======================
 Linux Kernel Selftests
+======================
 
 The kernel contains a set of "self tests" under the tools/testing/selftests/
 directory. These are intended to be small tests to exercise individual code
@@ -15,28 +17,33 @@ hotplug test is run on 2% of hotplug capable memory instead of 10%.
 Running the selftests (hotplug tests are run in limited mode)
 =============================================================
 
-To build the tests:
+To build the tests::
+
   $ make -C tools/testing/selftests
 
+To run the tests::
 
-To run the tests:
   $ make -C tools/testing/selftests run_tests
 
-To build and run the tests with a single command, use:
+To build and run the tests with a single command, use::
+
   $ make kselftest
 
-- note that some tests will require root privileges.
+Note that some tests will require root privileges.
 
 
 Running a subset of selftests
-========================================
+=============================
+
 You can use the "TARGETS" variable on the make command line to specify
 single test to run, or a list of tests to run.
 
-To run only tests targeted for a single subsystem:
-  $  make -C tools/testing/selftests TARGETS=ptrace run_tests
+To run only tests targeted for a single subsystem::
+
+  $ make -C tools/testing/selftests TARGETS=ptrace run_tests
+
+You can specify multiple tests to build and run::
 
-You can specify multiple tests to build and run:
   $  make TARGETS="size timers" kselftest
 
 See the top-level tools/testing/selftests/Makefile for the list of all
@@ -46,13 +53,15 @@ possible targets.
 Running the full range hotplug selftests
 ========================================
 
-To build the hotplug tests:
+To build the hotplug tests::
+
   $ make -C tools/testing/selftests hotplug
 
-To run the hotplug tests:
+To run the hotplug tests::
+
   $ make -C tools/testing/selftests run_hotplug
 
-- note that some tests will require root privileges.
+Note that some tests will require root privileges.
 
 
 Install selftests
@@ -62,11 +71,13 @@ You can use kselftest_install.sh tool installs selftests in default
 location which is tools/testing/selftests/kselftest or a user specified
 location.
 
-To install selftests in default location:
+To install selftests in default location::
+
    $ cd tools/testing/selftests
    $ ./kselftest_install.sh
 
-To install selftests in a user specified location:
+To install selftests in a user specified location::
+
    $ cd tools/testing/selftests
    $ ./kselftest_install.sh install_dir
 
@@ -77,10 +88,10 @@ Kselftest install as well as the Kselftest tarball provide a script
 named "run_kselftest.sh" to run the tests.
 
 You can simply do the following to run the installed Kselftests. Please
-note some tests will require root privileges.
+note some tests will require root privileges::
 
-cd kselftest
-./run_kselftest.sh
+   $ cd kselftest
+   $ ./run_kselftest.sh
 
 Contributing new tests
 ======================
@@ -96,14 +107,49 @@ In general, the rules for selftests are
  * Don't cause the top-level "make run_tests" to fail if your feature is
    unconfigured.
 
-Contributing new tests(details)
-===============================
+Contributing new tests (details)
+================================
 
  * Use TEST_GEN_XXX if such binaries or files are generated during
    compiling.
+
    TEST_PROGS, TEST_GEN_PROGS mean it is the excutable tested by
    default.
+
    TEST_PROGS_EXTENDED, TEST_GEN_PROGS_EXTENDED mean it is the
    executable which is not tested by default.
    TEST_FILES, TEST_GEN_FILES mean it is the file which is used by
    test.
+
+Test Harness
+============
+
+The kselftest_harness.h file contains useful helpers to build tests.  The tests
+from tools/testing/selftests/seccomp/seccomp_bpf.c can be used as example.
+
+Example
+-------
+
+.. kernel-doc:: tools/testing/selftests/kselftest_harness.h
+    :doc: example
+
+
+Helpers
+-------
+
+.. kernel-doc:: tools/testing/selftests/kselftest_harness.h
+    :functions: TH_LOG TEST TEST_SIGNAL FIXTURE FIXTURE_DATA FIXTURE_SETUP
+                FIXTURE_TEARDOWN TEST_F TEST_HARNESS_MAIN
+
+Operators
+---------
+
+.. kernel-doc:: tools/testing/selftests/kselftest_harness.h
+    :doc: operators
+
+.. kernel-doc:: tools/testing/selftests/kselftest_harness.h
+    :functions: ASSERT_EQ ASSERT_NE ASSERT_LT ASSERT_LE ASSERT_GT ASSERT_GE
+                ASSERT_NULL ASSERT_TRUE ASSERT_NULL ASSERT_TRUE ASSERT_FALSE
+                ASSERT_STREQ ASSERT_STRNE EXPECT_EQ EXPECT_NE EXPECT_LT
+                EXPECT_LE EXPECT_GT EXPECT_GE EXPECT_NULL EXPECT_TRUE
+                EXPECT_FALSE EXPECT_STREQ EXPECT_STRNE
diff --git a/MAINTAINERS b/MAINTAINERS
index a4f37b69a66c..b31be7522e45 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7337,9 +7337,10 @@ KERNEL SELFTEST FRAMEWORK
 M:	Shuah Khan <shuahkh@osg.samsung.com>
 M:	Shuah Khan <shuah@kernel.org>
 L:	linux-kselftest@vger.kernel.org
-T:	git git://git.kernel.org/pub/scm/shuah/linux-kselftest
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git
 S:	Maintained
-F:	tools/testing/selftests
+F:	tools/testing/selftests/
+F:	Documentation/dev-tools/kselftest*
 
 KERNEL VIRTUAL MACHINE (KVM)
 M:	Paolo Bonzini <pbonzini@redhat.com>
@@ -11740,6 +11741,7 @@ F:	kernel/seccomp.c
 F:	include/uapi/linux/seccomp.h
 F:	include/linux/seccomp.h
 F:	tools/testing/selftests/seccomp/*
+F:	tools/testing/selftests/kselftest_harness.h
 F:	Documentation/userspace-api/seccomp_filter.rst
 K:	\bsecure_computing
 K:	\bTIF_SECCOMP\b
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 00e2e4169b1e..948ec32e0c27 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4564,7 +4564,8 @@ static const char readme_msg[] =
 #endif
 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
 	"\t  accepts: event-definitions (one definition per line)\n"
-	"\t   Format: p|r[:[<group>/]<event>] <place> [<args>]\n"
+	"\t   Format: p[:[<group>/]<event>] <place> [<args>]\n"
+	"\t           r[maxactive][:[<group>/]<event>] <place> [<args>]\n"
 	"\t           -:[<group>/]<event>\n"
 #ifdef CONFIG_KPROBE_EVENTS
 	"\t    place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
diff --git a/tools/testing/selftests/breakpoints/breakpoint_test.c b/tools/testing/selftests/breakpoints/breakpoint_test.c
index 120895ab5505..f63356151ad4 100644
--- a/tools/testing/selftests/breakpoints/breakpoint_test.c
+++ b/tools/testing/selftests/breakpoints/breakpoint_test.c
@@ -16,6 +16,8 @@
 #include <signal.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <errno.h>
+#include <string.h>
 
 #include "../kselftest.h"
 
@@ -42,10 +44,9 @@ static void set_breakpoint_addr(void *addr, int n)
 
 	ret = ptrace(PTRACE_POKEUSER, child_pid,
 		     offsetof(struct user, u_debugreg[n]), addr);
-	if (ret) {
-		perror("Can't set breakpoint addr\n");
-		ksft_exit_fail();
-	}
+	if (ret)
+		ksft_exit_fail_msg("Can't set breakpoint addr: %s\n",
+			strerror(errno));
 }
 
 static void toggle_breakpoint(int n, int type, int len,
@@ -106,8 +107,8 @@ static void toggle_breakpoint(int n, int type, int len,
 	ret = ptrace(PTRACE_POKEUSER, child_pid,
 		     offsetof(struct user, u_debugreg[7]), dr7);
 	if (ret) {
-		perror("Can't set dr7");
-		ksft_exit_fail();
+		ksft_print_msg("Can't set dr7: %s\n", strerror(errno));
+		exit(-1);
 	}
 }
 
@@ -206,7 +207,7 @@ static void trigger_tests(void)
 
 	ret = ptrace(PTRACE_TRACEME, 0, NULL, 0);
 	if (ret) {
-		perror("Can't be traced?\n");
+		ksft_print_msg("Can't be traced? %s\n", strerror(errno));
 		return;
 	}
 
@@ -261,29 +262,30 @@ static void trigger_tests(void)
 
 static void check_success(const char *msg)
 {
-	const char *msg2;
 	int child_nr_tests;
 	int status;
+	int ret;
 
 	/* Wait for the child to SIGTRAP */
 	wait(&status);
 
-	msg2 = "Failed";
+	ret = 0;
 
 	if (WSTOPSIG(status) == SIGTRAP) {
 		child_nr_tests = ptrace(PTRACE_PEEKDATA, child_pid,
 					&nr_tests, 0);
 		if (child_nr_tests == nr_tests)
-			msg2 = "Ok";
-		if (ptrace(PTRACE_POKEDATA, child_pid, &trapped, 1)) {
-			perror("Can't poke\n");
-			ksft_exit_fail();
-		}
+			ret = 1;
+		if (ptrace(PTRACE_POKEDATA, child_pid, &trapped, 1))
+			ksft_exit_fail_msg("Can't poke: %s\n", strerror(errno));
 	}
 
 	nr_tests++;
 
-	printf("%s [%s]\n", msg, msg2);
+	if (ret)
+		ksft_test_result_pass(msg);
+	else
+		ksft_test_result_fail(msg);
 }
 
 static void launch_instruction_breakpoints(char *buf, int local, int global)
@@ -294,7 +296,7 @@ static void launch_instruction_breakpoints(char *buf, int local, int global)
 		set_breakpoint_addr(dummy_funcs[i], i);
 		toggle_breakpoint(i, BP_X, 1, local, global, 1);
 		ptrace(PTRACE_CONT, child_pid, NULL, 0);
-		sprintf(buf, "Test breakpoint %d with local: %d global: %d",
+		sprintf(buf, "Test breakpoint %d with local: %d global: %d\n",
 			i, local, global);
 		check_success(buf);
 		toggle_breakpoint(i, BP_X, 1, local, global, 0);
@@ -316,8 +318,9 @@ static void launch_watchpoints(char *buf, int mode, int len,
 		set_breakpoint_addr(&dummy_var[i], i);
 		toggle_breakpoint(i, mode, len, local, global, 1);
 		ptrace(PTRACE_CONT, child_pid, NULL, 0);
-		sprintf(buf, "Test %s watchpoint %d with len: %d local: "
-			"%d global: %d", mode_str, i, len, local, global);
+		sprintf(buf,
+			"Test %s watchpoint %d with len: %d local: %d global: %d\n",
+			mode_str, i, len, local, global);
 		check_success(buf);
 		toggle_breakpoint(i, mode, len, local, global, 0);
 	}
@@ -378,10 +381,12 @@ int main(int argc, char **argv)
 	pid_t pid;
 	int ret;
 
+	ksft_print_header();
+
 	pid = fork();
 	if (!pid) {
 		trigger_tests();
-		return 0;
+		exit(0);
 	}
 
 	child_pid = pid;
@@ -392,5 +397,5 @@ int main(int argc, char **argv)
 
 	wait(NULL);
 
-	return ksft_exit_pass();
+	ksft_exit_pass();
 }
diff --git a/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c b/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c
index 3897e996541e..960d02100c26 100644
--- a/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c
+++ b/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c
@@ -43,19 +43,25 @@ static void child(int size, int wr)
 	volatile uint8_t *addr = &var[32 + wr];
 
 	if (ptrace(PTRACE_TRACEME, 0, NULL, NULL) != 0) {
-		perror("ptrace(PTRACE_TRACEME) failed");
+		ksft_print_msg(
+			"ptrace(PTRACE_TRACEME) failed: %s\n",
+			strerror(errno));
 		_exit(1);
 	}
 
 	if (raise(SIGSTOP) != 0) {
-		perror("raise(SIGSTOP) failed");
+		ksft_print_msg(
+			"raise(SIGSTOP) failed: %s\n", strerror(errno));
 		_exit(1);
 	}
 
 	if ((uintptr_t) addr % size) {
-		perror("Wrong address write for the given size\n");
+		ksft_print_msg(
+			 "Wrong address write for the given size: %s\n",
+			 strerror(errno));
 		_exit(1);
 	}
+
 	switch (size) {
 	case 1:
 		*addr = 47;
@@ -100,12 +106,14 @@ static bool set_watchpoint(pid_t pid, int size, int wp)
 	if (ptrace(PTRACE_SETREGSET, pid, NT_ARM_HW_WATCH, &iov) == 0)
 		return true;
 
-	if (errno == EIO) {
-		printf("ptrace(PTRACE_SETREGSET, NT_ARM_HW_WATCH) "
-			"not supported on this hardware\n");
-		ksft_exit_skip();
-	}
-	perror("ptrace(PTRACE_SETREGSET, NT_ARM_HW_WATCH) failed");
+	if (errno == EIO)
+		ksft_print_msg(
+			"ptrace(PTRACE_SETREGSET, NT_ARM_HW_WATCH) not supported on this hardware: %s\n",
+			strerror(errno));
+
+	ksft_print_msg(
+		"ptrace(PTRACE_SETREGSET, NT_ARM_HW_WATCH) failed: %s\n",
+		strerror(errno));
 	return false;
 }
 
@@ -117,7 +125,8 @@ static bool run_test(int wr_size, int wp_size, int wr, int wp)
 	pid_t wpid;
 
 	if (pid < 0) {
-		perror("fork() failed");
+		ksft_test_result_fail(
+			"fork() failed: %s\n", strerror(errno));
 		return false;
 	}
 	if (pid == 0)
@@ -125,15 +134,17 @@ static bool run_test(int wr_size, int wp_size, int wr, int wp)
 
 	wpid = waitpid(pid, &status, __WALL);
 	if (wpid != pid) {
-		perror("waitpid() failed");
+		ksft_print_msg(
+			"waitpid() failed: %s\n", strerror(errno));
 		return false;
 	}
 	if (!WIFSTOPPED(status)) {
-		printf("child did not stop\n");
+		ksft_print_msg(
+			"child did not stop: %s\n", strerror(errno));
 		return false;
 	}
 	if (WSTOPSIG(status) != SIGSTOP) {
-		printf("child did not stop with SIGSTOP\n");
+		ksft_print_msg("child did not stop with SIGSTOP\n");
 		return false;
 	}
 
@@ -141,42 +152,49 @@ static bool run_test(int wr_size, int wp_size, int wr, int wp)
 		return false;
 
 	if (ptrace(PTRACE_CONT, pid, NULL, NULL) < 0) {
-		perror("ptrace(PTRACE_SINGLESTEP) failed");
+		ksft_print_msg(
+			"ptrace(PTRACE_SINGLESTEP) failed: %s\n",
+			strerror(errno));
 		return false;
 	}
 
 	alarm(3);
 	wpid = waitpid(pid, &status, __WALL);
 	if (wpid != pid) {
-		perror("waitpid() failed");
+		ksft_print_msg(
+			"waitpid() failed: %s\n", strerror(errno));
 		return false;
 	}
 	alarm(0);
 	if (WIFEXITED(status)) {
-		printf("child did not single-step\t");
+		ksft_print_msg("child did not single-step\n");
 		return false;
 	}
 	if (!WIFSTOPPED(status)) {
-		printf("child did not stop\n");
+		ksft_print_msg("child did not stop\n");
 		return false;
 	}
 	if (WSTOPSIG(status) != SIGTRAP) {
-		printf("child did not stop with SIGTRAP\n");
+		ksft_print_msg("child did not stop with SIGTRAP\n");
 		return false;
 	}
 	if (ptrace(PTRACE_GETSIGINFO, pid, NULL, &siginfo) != 0) {
-		perror("ptrace(PTRACE_GETSIGINFO)");
+		ksft_print_msg(
+			"ptrace(PTRACE_GETSIGINFO): %s\n",
+			strerror(errno));
 		return false;
 	}
 	if (siginfo.si_code != TRAP_HWBKPT) {
-		printf("Unexpected si_code %d\n", siginfo.si_code);
+		ksft_print_msg(
+			"Unexpected si_code %d\n", siginfo.si_code);
 		return false;
 	}
 
 	kill(pid, SIGKILL);
 	wpid = waitpid(pid, &status, 0);
 	if (wpid != pid) {
-		perror("waitpid() failed");
+		ksft_print_msg(
+			"waitpid() failed: %s\n", strerror(errno));
 		return false;
 	}
 	return true;
@@ -194,6 +212,8 @@ int main(int argc, char **argv)
 	int wr, wp, size;
 	bool result;
 
+	ksft_print_header();
+
 	act.sa_handler = sigalrm;
 	sigemptyset(&act.sa_mask);
 	act.sa_flags = 0;
@@ -201,14 +221,16 @@ int main(int argc, char **argv)
 	for (size = 1; size <= 32; size = size*2) {
 		for (wr = 0; wr <= 32; wr = wr + size) {
 			for (wp = wr - size; wp <= wr + size; wp = wp + size) {
-				printf("Test size = %d write offset = %d watchpoint offset = %d\t", size, wr, wp);
 				result = run_test(size, MIN(size, 8), wr, wp);
-				if ((result && wr == wp) || (!result && wr != wp)) {
-					printf("[OK]\n");
-					ksft_inc_pass_cnt();
-				} else {
-					printf("[FAILED]\n");
-					ksft_inc_fail_cnt();
+				if ((result && wr == wp) ||
+				    (!result && wr != wp))
+					ksft_test_result_pass(
+						"Test size = %d write offset = %d watchpoint offset = %d\n",
+						size, wr, wp);
+				else {
+					ksft_test_result_fail(
+						"Test size = %d write offset = %d watchpoint offset = %d\n",
+						size, wr, wp);
 					succeeded = false;
 				}
 			}
@@ -216,19 +238,18 @@ int main(int argc, char **argv)
 	}
 
 	for (size = 1; size <= 32; size = size*2) {
-		printf("Test size = %d write offset = %d watchpoint offset = -8\t", size, -size);
-
-		if (run_test(size, 8, -size, -8)) {
-			printf("[OK]\n");
-			ksft_inc_pass_cnt();
-		} else {
-			printf("[FAILED]\n");
-			ksft_inc_fail_cnt();
+		if (run_test(size, 8, -size, -8))
+			ksft_test_result_pass(
+				"Test size = %d write offset = %d watchpoint offset = -8\n",
+				size, -size);
+		else {
+			ksft_test_result_fail(
+				"Test size = %d write offset = %d watchpoint offset = -8\n",
+				size, -size);
 			succeeded = false;
 		}
 	}
 
-	ksft_print_cnts();
 	if (succeeded)
 		ksft_exit_pass();
 	else
diff --git a/tools/testing/selftests/breakpoints/step_after_suspend_test.c b/tools/testing/selftests/breakpoints/step_after_suspend_test.c
index 60b8a95dac26..3fece06e9f64 100644
--- a/tools/testing/selftests/breakpoints/step_after_suspend_test.c
+++ b/tools/testing/selftests/breakpoints/step_after_suspend_test.c
@@ -37,17 +37,19 @@ void child(int cpu)
 	CPU_ZERO(&set);
 	CPU_SET(cpu, &set);
 	if (sched_setaffinity(0, sizeof(set), &set) != 0) {
-		perror("sched_setaffinity() failed");
+		ksft_print_msg("sched_setaffinity() failed: %s\n",
+			strerror(errno));
 		_exit(1);
 	}
 
 	if (ptrace(PTRACE_TRACEME, 0, NULL, NULL) != 0) {
-		perror("ptrace(PTRACE_TRACEME) failed");
+		ksft_print_msg("ptrace(PTRACE_TRACEME) failed: %s\n",
+			strerror(errno));
 		_exit(1);
 	}
 
 	if (raise(SIGSTOP) != 0) {
-		perror("raise(SIGSTOP) failed");
+		ksft_print_msg("raise(SIGSTOP) failed: %s\n", strerror(errno));
 		_exit(1);
 	}
 
@@ -61,7 +63,7 @@ bool run_test(int cpu)
 	pid_t wpid;
 
 	if (pid < 0) {
-		perror("fork() failed");
+		ksft_print_msg("fork() failed: %s\n", strerror(errno));
 		return false;
 	}
 	if (pid == 0)
@@ -69,57 +71,64 @@ bool run_test(int cpu)
 
 	wpid = waitpid(pid, &status, __WALL);
 	if (wpid != pid) {
-		perror("waitpid() failed");
+		ksft_print_msg("waitpid() failed: %s\n", strerror(errno));
 		return false;
 	}
 	if (!WIFSTOPPED(status)) {
-		printf("child did not stop\n");
+		ksft_print_msg("child did not stop: %s\n", strerror(errno));
 		return false;
 	}
 	if (WSTOPSIG(status) != SIGSTOP) {
-		printf("child did not stop with SIGSTOP\n");
+		ksft_print_msg("child did not stop with SIGSTOP: %s\n",
+			strerror(errno));
 		return false;
 	}
 
 	if (ptrace(PTRACE_SINGLESTEP, pid, NULL, NULL) < 0) {
 		if (errno == EIO) {
-			printf("ptrace(PTRACE_SINGLESTEP) not supported on this architecture\n");
-			ksft_exit_skip();
+			ksft_exit_skip(
+				"ptrace(PTRACE_SINGLESTEP) not supported on this architecture: %s\n",
+				strerror(errno));
 		}
-		perror("ptrace(PTRACE_SINGLESTEP) failed");
+		ksft_print_msg("ptrace(PTRACE_SINGLESTEP) failed: %s\n",
+			strerror(errno));
 		return false;
 	}
 
 	wpid = waitpid(pid, &status, __WALL);
 	if (wpid != pid) {
-		perror("waitpid() failed");
+		ksft_print_msg("waitpid() failed: $s\n", strerror(errno));
 		return false;
 	}
 	if (WIFEXITED(status)) {
-		printf("child did not single-step\n");
+		ksft_print_msg("child did not single-step: %s\n",
+			strerror(errno));
 		return false;
 	}
 	if (!WIFSTOPPED(status)) {
-		printf("child did not stop\n");
+		ksft_print_msg("child did not stop: %s\n", strerror(errno));
 		return false;
 	}
 	if (WSTOPSIG(status) != SIGTRAP) {
-		printf("child did not stop with SIGTRAP\n");
+		ksft_print_msg("child did not stop with SIGTRAP: %s\n",
+			strerror(errno));
 		return false;
 	}
 
 	if (ptrace(PTRACE_CONT, pid, NULL, NULL) < 0) {
-		perror("ptrace(PTRACE_CONT) failed");
+		ksft_print_msg("ptrace(PTRACE_CONT) failed: %s\n",
+			strerror(errno));
 		return false;
 	}
 
 	wpid = waitpid(pid, &status, __WALL);
 	if (wpid != pid) {
-		perror("waitpid() failed");
+		ksft_print_msg("waitpid() failed: %s\n", strerror(errno));
 		return false;
 	}
 	if (!WIFEXITED(status)) {
-		printf("child did not exit after PTRACE_CONT\n");
+		ksft_print_msg("child did not exit after PTRACE_CONT: %s\n",
+			strerror(errno));
 		return false;
 	}
 
@@ -135,28 +144,21 @@ void suspend(void)
 	struct itimerspec spec = {};
 
 	power_state_fd = open("/sys/power/state", O_RDWR);
-	if (power_state_fd < 0) {
-		perror("open(\"/sys/power/state\") failed (is this test running as root?)");
-		ksft_exit_fail();
-	}
+	if (power_state_fd < 0)
+		ksft_exit_fail_msg(
+			"open(\"/sys/power/state\") failed (is this test running as root?)\n");
 
 	timerfd = timerfd_create(CLOCK_BOOTTIME_ALARM, 0);
-	if (timerfd < 0) {
-		perror("timerfd_create() failed");
-		ksft_exit_fail();
-	}
+	if (timerfd < 0)
+		ksft_exit_fail_msg("timerfd_create() failed\n");
 
 	spec.it_value.tv_sec = 5;
 	err = timerfd_settime(timerfd, 0, &spec, NULL);
-	if (err < 0) {
-		perror("timerfd_settime() failed");
-		ksft_exit_fail();
-	}
+	if (err < 0)
+		ksft_exit_fail_msg("timerfd_settime() failed\n");
 
-	if (write(power_state_fd, "mem", strlen("mem")) != strlen("mem")) {
-		perror("entering suspend failed");
-		ksft_exit_fail();
-	}
+	if (write(power_state_fd, "mem", strlen("mem")) != strlen("mem"))
+		ksft