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, 257 insertions, 0 deletions

diff --git a/tools/perf/tests/time-utils-test.c b/tools/perf/tests/time-utils-test.c
new file mode 100644
index 000000000..90a9a4b4f
--- /dev/null
+++ b/tools/perf/tests/time-utils-test.c
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/compiler.h>
+#include <linux/time64.h>
+#include <inttypes.h>
+#include <string.h>
+#include "time-utils.h"
+#include "evlist.h"
+#include "session.h"
+#include "debug.h"
+#include "tests.h"
+
+static bool test__parse_nsec_time(const char *str, u64 expected)
+{
+	u64 ptime;
+	int err;
+
+	pr_debug("\nparse_nsec_time(\"%s\")\n", str);
+
+	err = parse_nsec_time(str, &ptime);
+	if (err) {
+		pr_debug("error %d\n", err);
+		return false;
+	}
+
+	if (ptime != expected) {
+		pr_debug("Failed. ptime %" PRIu64 " expected %" PRIu64 "\n",
+			 ptime, expected);
+		return false;
+	}
+
+	pr_debug("%" PRIu64 "\n", ptime);
+
+	return true;
+}
+
+static bool test__perf_time__parse_str(const char *ostr, u64 start, u64 end)
+{
+	struct perf_time_interval ptime;
+	int err;
+
+	pr_debug("\nperf_time__parse_str(\"%s\")\n", ostr);
+
+	err = perf_time__parse_str(&ptime, ostr);
+	if (err) {
+		pr_debug("Error %d\n", err);
+		return false;
+	}
+
+	if (ptime.start != start || ptime.end != end) {
+		pr_debug("Failed. Expected %" PRIu64 " to %" PRIu64 "\n",
+			 start, end);
+		return false;
+	}
+
+	return true;
+}
+
+#define TEST_MAX 64
+
+struct test_data {
+	const char *str;
+	u64 first;
+	u64 last;
+	struct perf_time_interval ptime[TEST_MAX];
+	int num;
+	u64 skip[TEST_MAX];
+	u64 noskip[TEST_MAX];
+};
+
+static bool test__perf_time__parse_for_ranges(struct test_data *d)
+{
+	struct evlist *evlist = evlist__new();
+	struct perf_session session = { .evlist = evlist };
+	struct perf_time_interval *ptime = NULL;
+	int range_size, range_num;
+	bool pass = false;
+	int i, err;
+
+	if (!evlist) {
+		pr_debug("Missing evlist\n");
+		return false;
+	}
+	evlist__set_first_sample_time(evlist, d->first);
+	evlist__set_last_sample_time(evlist, d->last);
+	pr_debug("\nperf_time__parse_for_ranges(\"%s\")\n", d->str);
+
+	if (strchr(d->str, '%'))
+		pr_debug("first_sample_time %" PRIu64 " last_sample_time %" PRIu64 "\n",
+			 d->first, d->last);
+
+	err = perf_time__parse_for_ranges(d->str, &session, &ptime, &range_size,
+					  &range_num);
+	if (err) {
+		pr_debug("error %d\n", err);
+		goto out;
+	}
+
+	if (range_size < d->num || range_num != d->num) {
+		pr_debug("bad size: range_size %d range_num %d expected num %d\n",
+			 range_size, range_num, d->num);
+		goto out;
+	}
+
+	for (i = 0; i < d->num; i++) {
+		if (ptime[i].start != d->ptime[i].start ||
+		    ptime[i].end != d->ptime[i].end) {
+			pr_debug("bad range %d expected %" PRIu64 " to %" PRIu64 "\n",
+				 i, d->ptime[i].start, d->ptime[i].end);
+			goto out;
+		}
+	}
+
+	if (perf_time__ranges_skip_sample(ptime, d->num, 0)) {
+		pr_debug("failed to keep 0\n");
+		goto out;
+	}
+
+	for (i = 0; i < TEST_MAX; i++) {
+		if (d->skip[i] &&
+		    !perf_time__ranges_skip_sample(ptime, d->num, d->skip[i])) {
+			pr_debug("failed to skip %" PRIu64 "\n", d->skip[i]);
+			goto out;
+		}
+		if (d->noskip[i] &&
+		    perf_time__ranges_skip_sample(ptime, d->num, d->noskip[i])) {
+			pr_debug("failed to keep %" PRIu64 "\n", d->noskip[i]);
+			goto out;
+		}
+	}
+
+	pass = true;
+out:
+	evlist__put(evlist);
+	free(ptime);
+	return pass;
+}
+
+static int test__time_utils(struct test_suite *t __maybe_unused, int subtest __maybe_unused)
+{
+	bool pass = true;
+
+	pass &= test__parse_nsec_time("0", 0);
+	pass &= test__parse_nsec_time("1", 1000000000ULL);
+	pass &= test__parse_nsec_time("0.000000001", 1);
+	pass &= test__parse_nsec_time("1.000000001", 1000000001ULL);
+	pass &= test__parse_nsec_time("123456.123456", 123456123456000ULL);
+	pass &= test__parse_nsec_time("1234567.123456789", 1234567123456789ULL);
+	pass &= test__parse_nsec_time("18446744073.709551615",
+				      0xFFFFFFFFFFFFFFFFULL);
+
+	pass &= test__perf_time__parse_str("1234567.123456789,1234567.123456789",
+					   1234567123456789ULL, 1234567123456789ULL);
+	pass &= test__perf_time__parse_str("1234567.123456789,1234567.123456790",
+					   1234567123456789ULL, 1234567123456790ULL);
+	pass &= test__perf_time__parse_str("1234567.123456789,",
+					   1234567123456789ULL, 0);
+	pass &= test__perf_time__parse_str(",1234567.123456789",
+					   0, 1234567123456789ULL);
+	pass &= test__perf_time__parse_str("0,1234567.123456789",
+					   0, 1234567123456789ULL);
+
+	{
+		u64 b = 1234567123456789ULL;
+		struct test_data d = {
+			.str   = "1234567.123456789,1234567.123456790",
+			.ptime = { {b, b + 1}, },
+			.num = 1,
+			.skip = { b - 1, b + 2, },
+			.noskip = { b, b + 1, },
+		};
+
+		pass &= test__perf_time__parse_for_ranges(&d);
+	}
+
+	{
+		u64 b = 1234567123456789ULL;
+		u64 c = 7654321987654321ULL;
+		u64 e = 8000000000000000ULL;
+		struct test_data d = {
+			.str   = "1234567.123456789,1234567.123456790 "
+				 "7654321.987654321,7654321.987654444 "
+				 "8000000,8000000.000000005",
+			.ptime = { {b, b + 1}, {c, c + 123}, {e, e + 5}, },
+			.num = 3,
+			.skip = { b - 1, b + 2, c - 1, c + 124, e - 1, e + 6 },
+			.noskip = { b, b + 1, c, c + 123, e, e + 5 },
+		};
+
+		pass &= test__perf_time__parse_for_ranges(&d);
+	}
+
+	{
+		u64 b = 7654321ULL * NSEC_PER_SEC;
+		struct test_data d = {
+			.str    = "10%/1",
+			.first  = b,
+			.last   = b + 100,
+			.ptime  = { {b, b + 9}, },
+			.num    = 1,
+			.skip   = { b - 1, b + 10, },
+			.noskip = { b, b + 9, },
+		};
+
+		pass &= test__perf_time__parse_for_ranges(&d);
+	}
+
+	{
+		u64 b = 7654321ULL * NSEC_PER_SEC;
+		struct test_data d = {
+			.str    = "10%/2",
+			.first  = b,
+			.last   = b + 100,
+			.ptime  = { {b + 10, b + 19}, },
+			.num    = 1,
+			.skip   = { b + 9, b + 20, },
+			.noskip = { b + 10, b + 19, },
+		};
+
+		pass &= test__perf_time__parse_for_ranges(&d);
+	}
+
+	{
+		u64 b = 11223344ULL * NSEC_PER_SEC;
+		struct test_data d = {
+			.str    = "10%/1,10%/2",
+			.first  = b,
+			.last   = b + 100,
+			.ptime  = { {b, b + 9}, {b + 10, b + 19}, },
+			.num    = 2,
+			.skip   = { b - 1, b + 20, },
+			.noskip = { b, b + 8, b + 9, b + 10, b + 11, b + 12, b + 19, },
+		};
+
+		pass &= test__perf_time__parse_for_ranges(&d);
+	}
+
+	{
+		u64 b = 11223344ULL * NSEC_PER_SEC;
+		struct test_data d = {
+			.str    = "10%/1,10%/3,10%/10",
+			.first  = b,
+			.last   = b + 100,
+			.ptime  = { {b, b + 9}, {b + 20, b + 29}, { b + 90, b + 100}, },
+			.num    = 3,
+			.skip   = { b - 1, b + 10, b + 19, b + 30, b + 89, b + 101 },
+			.noskip = { b, b + 9, b + 20, b + 29, b + 90, b + 100},
+		};
+
+		pass &= test__perf_time__parse_for_ranges(&d);
+	}
+
+	pr_debug("\n");
+
+	return pass ? 0 : TEST_FAIL;
+}
+
+DEFINE_SUITE("time utils", time_utils);