ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 490 insertions, 0 deletions

diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h
new file mode 100644
index 000000000..ae18c491a
--- /dev/null
+++ b/tools/testing/selftests/kselftest.h
@@ -0,0 +1,490 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * kselftest.h:	low-level kselftest framework to include from
+ *		selftest programs. When possible, please use
+ *		kselftest_harness.h instead.
+ *
+ * Copyright (c) 2014 Shuah Khan <shuahkh@osg.samsung.com>
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ *
+ * Using this API consists of first counting how many tests your code
+ * has to run, and then starting up the reporting:
+ *
+ *     ksft_print_header();
+ *     ksft_set_plan(total_number_of_tests);
+ *
+ * For each test, report any progress, debugging, etc with:
+ *
+ *     ksft_print_msg(fmt, ...);
+ *     ksft_perror(msg);
+ *
+ * and finally report the pass/fail/skip/xfail/xpass state of the test
+ * with one of:
+ *
+ *     ksft_test_result(condition, fmt, ...);
+ *     ksft_test_result_report(result, fmt, ...);
+ *     ksft_test_result_pass(fmt, ...);
+ *     ksft_test_result_fail(fmt, ...);
+ *     ksft_test_result_skip(fmt, ...);
+ *     ksft_test_result_xfail(fmt, ...);
+ *     ksft_test_result_xpass(fmt, ...);
+ *     ksft_test_result_error(fmt, ...);
+ *     ksft_test_result_code(exit_code, test_name, fmt, ...);
+ *
+ * When all tests are finished, clean up and exit the program with one of:
+ *
+ *    ksft_finished();
+ *    ksft_exit(condition);
+ *    ksft_exit_pass();
+ *    ksft_exit_fail();
+ *
+ * If the program wants to report details on why the entire program has
+ * failed, it can instead exit with a message (this is usually done when
+ * the program is aborting before finishing all tests):
+ *
+ *    ksft_exit_fail_msg(fmt, ...);
+ *    ksft_exit_fail_perror(msg);
+ *
+ */
+#ifndef __KSELFTEST_H
+#define __KSELFTEST_H
+
+#ifndef NOLIBC
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <string.h>
+#include <stdio.h>
+#include <sys/utsname.h>
+#endif
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+#endif
+
+#if defined(__i386__) || defined(__x86_64__) /* arch */
+/*
+ * gcc cpuid.h provides __cpuid_count() since v4.4.
+ * Clang/LLVM cpuid.h provides  __cpuid_count() since v3.4.0.
+ *
+ * Provide local define for tests needing __cpuid_count() because
+ * selftests need to work in older environments that do not yet
+ * have __cpuid_count().
+ */
+#ifndef __cpuid_count
+#define __cpuid_count(level, count, a, b, c, d)				\
+	__asm__ __volatile__ ("cpuid\n\t"				\
+			      : "=a" (a), "=b" (b), "=c" (c), "=d" (d)	\
+			      : "0" (level), "2" (count))
+#endif
+#endif /* end arch */
+
+/* define kselftest exit codes */
+#define KSFT_PASS  0
+#define KSFT_FAIL  1
+#define KSFT_XFAIL 2
+#define KSFT_XPASS 3
+#define KSFT_SKIP  4
+
+#ifndef __noreturn
+#define __noreturn       __attribute__((__noreturn__))
+#endif
+#define __printf(a, b)   __attribute__((format(printf, a, b)))
+
+#ifndef __always_unused
+#define __always_unused __attribute__((__unused__))
+#endif
+
+#ifndef __maybe_unused
+#define __maybe_unused __attribute__((__unused__))
+#endif
+
+/* counters */
+struct ksft_count {
+	unsigned int ksft_pass;
+	unsigned int ksft_fail;
+	unsigned int ksft_xfail;
+	unsigned int ksft_xpass;
+	unsigned int ksft_xskip;
+	unsigned int ksft_error;
+};
+
+static struct ksft_count ksft_cnt;
+static unsigned int ksft_plan;
+static bool ksft_debug_enabled;
+
+static inline unsigned int ksft_test_num(void)
+{
+	return ksft_cnt.ksft_pass + ksft_cnt.ksft_fail +
+		ksft_cnt.ksft_xfail + ksft_cnt.ksft_xpass +
+		ksft_cnt.ksft_xskip + ksft_cnt.ksft_error;
+}
+
+static inline void ksft_inc_pass_cnt(void) { ksft_cnt.ksft_pass++; }
+static inline void ksft_inc_fail_cnt(void) { ksft_cnt.ksft_fail++; }
+static inline void ksft_inc_xfail_cnt(void) { ksft_cnt.ksft_xfail++; }
+static inline void ksft_inc_xpass_cnt(void) { ksft_cnt.ksft_xpass++; }
+static inline void ksft_inc_xskip_cnt(void) { ksft_cnt.ksft_xskip++; }
+static inline void ksft_inc_error_cnt(void) { ksft_cnt.ksft_error++; }
+
+static inline int ksft_get_pass_cnt(void) { return ksft_cnt.ksft_pass; }
+static inline int ksft_get_fail_cnt(void) { return ksft_cnt.ksft_fail; }
+static inline int ksft_get_xfail_cnt(void) { return ksft_cnt.ksft_xfail; }
+static inline int ksft_get_xpass_cnt(void) { return ksft_cnt.ksft_xpass; }
+static inline int ksft_get_xskip_cnt(void) { return ksft_cnt.ksft_xskip; }
+static inline int ksft_get_error_cnt(void) { return ksft_cnt.ksft_error; }
+
+static inline void ksft_print_header(void)
+{
+	/*
+	 * Force line buffering; If stdout is not connected to a terminal, it
+	 * will otherwise default to fully buffered, which can cause output
+	 * duplication if there is content in the buffer when fork()ing. If
+	 * there is a crash, line buffering also means the most recent output
+	 * line will be visible.
+	 */
+	setvbuf(stdout, NULL, _IOLBF, 0);
+
+	if (!(getenv("KSFT_TAP_LEVEL")))
+		printf("TAP version 13\n");
+}
+
+static inline void ksft_set_plan(unsigned int plan)
+{
+	ksft_plan = plan;
+	printf("1..%u\n", ksft_plan);
+}
+
+static inline void ksft_print_cnts(void)
+{
+	if (ksft_cnt.ksft_xskip > 0)
+		printf(
+			"# %u skipped test(s) detected. Consider enabling relevant config options to improve coverage.\n",
+			ksft_cnt.ksft_xskip
+		);
+	if (ksft_plan != ksft_test_num())
+		printf("# Planned tests != run tests (%u != %u)\n",
+			ksft_plan, ksft_test_num());
+	printf("# Totals: pass:%u fail:%u xfail:%u xpass:%u skip:%u error:%u\n",
+		ksft_cnt.ksft_pass, ksft_cnt.ksft_fail,
+		ksft_cnt.ksft_xfail, ksft_cnt.ksft_xpass,
+		ksft_cnt.ksft_xskip, ksft_cnt.ksft_error);
+}
+
+static inline __printf(1, 2) void ksft_print_msg(const char *msg, ...)
+{
+	int saved_errno = errno;
+	va_list args;
+
+	va_start(args, msg);
+	printf("# ");
+	errno = saved_errno;
+	vprintf(msg, args);
+	va_end(args);
+}
+
+static inline void ksft_print_dbg_msg(const char *msg, ...)
+{
+	va_list args;
+
+	if (!ksft_debug_enabled)
+		return;
+
+	va_start(args, msg);
+	ksft_print_msg(msg, args);
+	va_end(args);
+}
+
+static inline void ksft_perror(const char *msg)
+{
+	ksft_print_msg("%s: %s (%d)\n", msg, strerror(errno), errno);
+}
+
+static inline __printf(1, 2) void ksft_test_result_pass(const char *msg, ...)
+{
+	int saved_errno = errno;
+	va_list args;
+
+	ksft_cnt.ksft_pass++;
+
+	va_start(args, msg);
+	printf("ok %u ", ksft_test_num());
+	errno = saved_errno;
+	vprintf(msg, args);
+	va_end(args);
+}
+
+static inline __printf(1, 2) void ksft_test_result_fail(const char *msg, ...)
+{
+	int saved_errno = errno;
+	va_list args;
+
+	ksft_cnt.ksft_fail++;
+
+	va_start(args, msg);
+	printf("not ok %u ", ksft_test_num());
+	errno = saved_errno;
+	vprintf(msg, args);
+	va_end(args);
+}
+
+/**
+ * ksft_test_result() - Report test success based on truth of condition
+ *
+ * @condition: if true, report test success, otherwise failure.
+ */
+#define ksft_test_result(condition, fmt, ...) do {	\
+	if (!!(condition))				\
+		ksft_test_result_pass(fmt, ##__VA_ARGS__);\
+	else						\
+		ksft_test_result_fail(fmt, ##__VA_ARGS__);\
+	} while (0)
+
+static inline __printf(1, 2) void ksft_test_result_xfail(const char *msg, ...)
+{
+	int saved_errno = errno;
+	va_list args;
+
+	ksft_cnt.ksft_xfail++;
+
+	va_start(args, msg);
+	printf("ok %u # XFAIL ", ksft_test_num());
+	errno = saved_errno;
+	vprintf(msg, args);
+	va_end(args);
+}
+
+static inline __printf(1, 2) void ksft_test_result_xpass(const char *msg, ...)
+{
+	int saved_errno = errno;
+	va_list args;
+
+	ksft_cnt.ksft_xpass++;
+
+	va_start(args, msg);
+	printf("ok %u # XPASS ", ksft_test_num());
+	errno = saved_errno;
+	vprintf(msg, args);
+	va_end(args);
+}
+
+static inline __printf(1, 2) void ksft_test_result_skip(const char *msg, ...)
+{
+	int saved_errno = errno;
+	va_list args;
+
+	ksft_cnt.ksft_xskip++;
+
+	va_start(args, msg);
+	printf("ok %u # SKIP ", ksft_test_num());
+	errno = saved_errno;
+	vprintf(msg, args);
+	va_end(args);
+}
+
+/* TODO: how does "error" differ from "fail" or "skip"? */
+static inline __printf(1, 2) void ksft_test_result_error(const char *msg, ...)
+{
+	int saved_errno = errno;
+	va_list args;
+
+	ksft_cnt.ksft_error++;
+
+	va_start(args, msg);
+	printf("not ok %u # error ", ksft_test_num());
+	errno = saved_errno;
+	vprintf(msg, args);
+	va_end(args);
+}
+
+static inline __printf(3, 4)
+void ksft_test_result_code(int exit_code, const char *test_name,
+			   const char *msg, ...)
+{
+	const char *tap_code = "ok";
+	const char *directive = "";
+	int saved_errno = errno;
+	va_list args;
+
+	switch (exit_code) {
+	case KSFT_PASS:
+		ksft_cnt.ksft_pass++;
+		break;
+	case KSFT_XFAIL:
+		directive = " # XFAIL ";
+		ksft_cnt.ksft_xfail++;
+		break;
+	case KSFT_XPASS:
+		directive = " # XPASS ";
+		ksft_cnt.ksft_xpass++;
+		break;
+	case KSFT_SKIP:
+		directive = " # SKIP ";
+		ksft_cnt.ksft_xskip++;
+		break;
+	case KSFT_FAIL:
+	default:
+		tap_code = "not ok";
+		ksft_cnt.ksft_fail++;
+		break;
+	}
+
+	/* Docs seem to call for double space if directive is absent */
+	if (!directive[0] && msg)
+		directive = " #  ";
+
+	printf("%s %u %s%s", tap_code, ksft_test_num(), test_name, directive);
+	errno = saved_errno;
+	if (msg) {
+		va_start(args, msg);
+		vprintf(msg, args);
+		va_end(args);
+	}
+	printf("\n");
+}
+
+/**
+ * ksft_test_result_report() - Report test result based on a kselftest exit code
+ *
+ * @result: a kselftest exit code
+ */
+#define ksft_test_result_report(result, fmt, ...) do {		\
+	switch (result) {					\
+	case KSFT_PASS:						\
+		ksft_test_result_pass(fmt, ##__VA_ARGS__);	\
+		break;						\
+	case KSFT_FAIL:						\
+		ksft_test_result_fail(fmt, ##__VA_ARGS__);	\
+		break;						\
+	case KSFT_XFAIL:					\
+		ksft_test_result_xfail(fmt, ##__VA_ARGS__);	\
+		break;						\
+	case KSFT_XPASS:					\
+		ksft_test_result_xpass(fmt, ##__VA_ARGS__);	\
+		break;						\
+	case KSFT_SKIP:						\
+		ksft_test_result_skip(fmt, ##__VA_ARGS__);	\
+		break;						\
+	} } while (0)
+
+static inline __noreturn void ksft_exit_pass(void)
+{
+	ksft_print_cnts();
+	exit(KSFT_PASS);
+}
+
+static inline __noreturn void ksft_exit_fail(void)
+{
+	ksft_print_cnts();
+	exit(KSFT_FAIL);
+}
+
+/**
+ * ksft_exit() - Exit selftest based on truth of condition
+ *
+ * @condition: if true, exit self test with success, otherwise fail.
+ */
+#define ksft_exit(condition) do {	\
+	if (!!(condition))		\
+		ksft_exit_pass();	\
+	else				\
+		ksft_exit_fail();	\
+	} while (0)
+
+/**
+ * ksft_finished() - Exit selftest with success if all tests passed
+ */
+#define ksft_finished()			\
+	ksft_exit(ksft_plan ==		\
+		  ksft_cnt.ksft_pass +	\
+		  ksft_cnt.ksft_xpass +	\
+		  ksft_cnt.ksft_xfail +	\
+		  ksft_cnt.ksft_xskip)
+
+static inline __noreturn __printf(1, 2) void ksft_exit_fail_msg(const char *msg, ...)
+{
+	int saved_errno = errno;
+	va_list args;
+
+	va_start(args, msg);
+	printf("Bail out! ");
+	errno = saved_errno;
+	vprintf(msg, args);
+	va_end(args);
+
+	ksft_print_cnts();
+	exit(KSFT_FAIL);
+}
+
+static inline __noreturn void ksft_exit_fail_perror(const char *msg)
+{
+	ksft_exit_fail_msg("%s: %s (%d)\n", msg, strerror(errno), errno);
+}
+
+static inline __noreturn void ksft_exit_xfail(void)
+{
+	ksft_print_cnts();
+	exit(KSFT_XFAIL);
+}
+
+static inline __noreturn void ksft_exit_xpass(void)
+{
+	ksft_print_cnts();
+	exit(KSFT_XPASS);
+}
+
+static inline __noreturn __printf(1, 2) void ksft_exit_skip(const char *msg, ...)
+{
+	int saved_errno = errno;
+	va_list args;
+
+	va_start(args, msg);
+
+	/*
+	 * FIXME: several tests misuse ksft_exit_skip so produce
+	 * something sensible if some tests have already been run
+	 * or a plan has been printed.  Those tests should use
+	 * ksft_test_result_skip or ksft_exit_fail_msg instead.
+	 */
+	if (ksft_plan || ksft_test_num()) {
+		ksft_cnt.ksft_xskip++;
+		printf("ok %u # SKIP ", ksft_test_num());
+	} else {
+		printf("1..0 # SKIP ");
+	}
+	if (msg) {
+		errno = saved_errno;
+		vprintf(msg, args);
+		va_end(args);
+	}
+	if (ksft_test_num())
+		ksft_print_cnts();
+	exit(KSFT_SKIP);
+}
+
+static inline int ksft_min_kernel_version(unsigned int min_major,
+					  unsigned int min_minor)
+{
+	unsigned int major, minor;
+	struct utsname info;
+
+	if (uname(&info) || sscanf(info.release, "%u.%u.", &major, &minor) != 2)
+		ksft_exit_fail_msg("Can't parse kernel version\n");
+
+	return major > min_major || (major == min_major && minor >= min_minor);
+}
+
+static inline void ksft_reset_state(void)
+{
+	ksft_cnt.ksft_pass = 0;
+	ksft_cnt.ksft_fail = 0;
+	ksft_cnt.ksft_xfail = 0;
+	ksft_cnt.ksft_xpass = 0;
+	ksft_cnt.ksft_xskip = 0;
+	ksft_cnt.ksft_error = 0;
+	ksft_plan = 0;
+}
+
+#endif /* __KSELFTEST_H */