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, 493 insertions, 0 deletions

diff --git a/tools/perf/tests/sample-parsing.c b/tools/perf/tests/sample-parsing.c
new file mode 100644
index 000000000..32dbc4844
--- /dev/null
+++ b/tools/perf/tests/sample-parsing.c
@@ -0,0 +1,493 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdbool.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <string.h>
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+#include "map_symbol.h"
+#include "branch.h"
+#include "event.h"
+#include "evsel.h"
+#include "debug.h"
+#include "util/synthetic-events.h"
+#include "util/util.h"
+
+#include "tests.h"
+
+#define COMP(m) do {					\
+	if (s1->m != s2->m) {				\
+		pr_debug("Samples differ at '"#m"'\n");	\
+		return false;				\
+	}						\
+} while (0)
+
+#define MCOMP(m) do {					\
+	if (memcmp(&s1->m, &s2->m, sizeof(s1->m))) {	\
+		pr_debug("Samples differ at '"#m"'\n");	\
+		return false;				\
+	}						\
+} while (0)
+
+/*
+ * Hardcode the expected values for branch_entry flags.
+ * These are based on the input value (213) specified
+ * in branch_stack variable.
+ */
+#define BS_EXPECTED_BE	0xa000d00000000000
+#define BS_EXPECTED_LE	0x1aa00000000
+#define FLAG(s)	s->branch_stack->entries[i].flags
+
+static bool samples_same(struct perf_sample *s1,
+			 struct perf_sample *s2,
+			 u64 type, u64 read_format, bool needs_swap)
+{
+	size_t i;
+
+	if (type & PERF_SAMPLE_IDENTIFIER)
+		COMP(id);
+
+	if (type & PERF_SAMPLE_IP)
+		COMP(ip);
+
+	if (type & PERF_SAMPLE_TID) {
+		COMP(pid);
+		COMP(tid);
+	}
+
+	if (type & PERF_SAMPLE_TIME)
+		COMP(time);
+
+	if (type & PERF_SAMPLE_ADDR)
+		COMP(addr);
+
+	if (type & PERF_SAMPLE_ID)
+		COMP(id);
+
+	if (type & PERF_SAMPLE_STREAM_ID)
+		COMP(stream_id);
+
+	if (type & PERF_SAMPLE_CPU)
+		COMP(cpu);
+
+	if (type & PERF_SAMPLE_PERIOD)
+		COMP(period);
+
+	if (type & PERF_SAMPLE_READ) {
+		if (read_format & PERF_FORMAT_GROUP)
+			COMP(read.group.nr);
+		else
+			COMP(read.one.value);
+		if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+			COMP(read.time_enabled);
+		if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+			COMP(read.time_running);
+		/* PERF_FORMAT_ID is forced for PERF_SAMPLE_READ */
+		if (read_format & PERF_FORMAT_GROUP) {
+			struct sample_read_value *v1 = s1->read.group.values;
+			struct sample_read_value *v2 = s2->read.group.values;
+
+			for (i = 0; i < s1->read.group.nr; i++) {
+				if (v1->value != v2->value) {
+					pr_debug("Samples differ at 'read.group.values[].value'\n");
+					return false;
+				}
+
+				if (v1->id != v2->id) {
+					pr_debug("Samples differ at 'read.group.values[].id'\n");
+					return false;
+				}
+
+				if (read_format & PERF_FORMAT_LOST &&
+				    v1->lost != v2->lost) {
+					pr_debug("Samples differ at 'read.group.values[].lost'\n");
+					return false;
+				}
+				v1 = next_sample_read_value(v1, read_format);
+				v2 = next_sample_read_value(v2, read_format);
+			}
+		} else {
+			COMP(read.one.id);
+			if (read_format & PERF_FORMAT_LOST)
+				COMP(read.one.lost);
+		}
+	}
+
+	if (type & PERF_SAMPLE_CALLCHAIN) {
+		COMP(callchain->nr);
+		for (i = 0; i < s1->callchain->nr; i++)
+			COMP(callchain->ips[i]);
+	}
+
+	if (type & PERF_SAMPLE_RAW) {
+		COMP(raw_size);
+		if (memcmp(s1->raw_data, s2->raw_data, s1->raw_size)) {
+			pr_debug("Samples differ at 'raw_data'\n");
+			return false;
+		}
+	}
+
+	if (type & PERF_SAMPLE_BRANCH_STACK) {
+		COMP(branch_stack->nr);
+		COMP(branch_stack->hw_idx);
+		for (i = 0; i < s1->branch_stack->nr; i++) {
+			if (needs_swap)
+				return ((host_is_bigendian()) ?
+					(FLAG(s2).value == BS_EXPECTED_BE) :
+					(FLAG(s2).value == BS_EXPECTED_LE));
+			else
+				MCOMP(branch_stack->entries[i]);
+		}
+	}
+
+	if (type & PERF_SAMPLE_REGS_USER) {
+		struct regs_dump *s1_regs = perf_sample__user_regs(s1);
+		struct regs_dump *s2_regs = perf_sample__user_regs(s2);
+		size_t sz = hweight_long(s1_regs->mask) * sizeof(u64);
+
+		COMP(user_regs->mask);
+		COMP(user_regs->abi);
+		if (s1_regs->abi &&
+		    (!s1_regs->regs || !s2_regs->regs ||
+		     memcmp(s1_regs->regs, s2_regs->regs, sz))) {
+			pr_debug("Samples differ at 'user_regs'\n");
+			return false;
+		}
+	}
+
+	if (type & PERF_SAMPLE_STACK_USER) {
+		COMP(user_stack.size);
+		if (memcmp(s1->user_stack.data, s2->user_stack.data,
+			   s1->user_stack.size)) {
+			pr_debug("Samples differ at 'user_stack'\n");
+			return false;
+		}
+	}
+
+	if (type & PERF_SAMPLE_WEIGHT)
+		COMP(weight);
+
+	if (type & PERF_SAMPLE_WEIGHT_STRUCT) {
+		COMP(weight);
+		COMP(ins_lat);
+		COMP(weight3);
+	}
+
+	if (type & PERF_SAMPLE_DATA_SRC)
+		COMP(data_src);
+
+	if (type & PERF_SAMPLE_TRANSACTION)
+		COMP(transaction);
+
+	if (type & PERF_SAMPLE_REGS_INTR) {
+		struct regs_dump *s1_regs = perf_sample__intr_regs(s1);
+		struct regs_dump *s2_regs = perf_sample__intr_regs(s2);
+		size_t sz = hweight_long(s1_regs->mask) * sizeof(u64);
+
+		COMP(intr_regs->mask);
+		COMP(intr_regs->abi);
+		if (s1_regs->abi &&
+		    (!s1_regs->regs || !s2_regs->regs ||
+		     memcmp(s1_regs->regs, s2_regs->regs, sz))) {
+			pr_debug("Samples differ at 'intr_regs'\n");
+			return false;
+		}
+	}
+
+	if (type & PERF_SAMPLE_PHYS_ADDR)
+		COMP(phys_addr);
+
+	if (type & PERF_SAMPLE_CGROUP)
+		COMP(cgroup);
+
+	if (type & PERF_SAMPLE_DATA_PAGE_SIZE)
+		COMP(data_page_size);
+
+	if (type & PERF_SAMPLE_CODE_PAGE_SIZE)
+		COMP(code_page_size);
+
+	if (type & PERF_SAMPLE_AUX) {
+		COMP(aux_sample.size);
+		if (memcmp(s1->aux_sample.data, s2->aux_sample.data,
+			   s1->aux_sample.size)) {
+			pr_debug("Samples differ at 'aux_sample'\n");
+			return false;
+		}
+	}
+
+	return true;
+}
+
+static int do_test(u64 sample_type, u64 sample_regs, u64 read_format)
+{
+	struct perf_event_attr attr = {
+		.sample_type = sample_type,
+		.read_format = read_format,
+	};
+	struct evsel *evsel;
+	union perf_event *event;
+	union {
+		struct ip_callchain callchain;
+		u64 data[64];
+	} callchain = {
+		/* 3 ips */
+		.data = {3, 201, 202, 203},
+	};
+	union {
+		struct branch_stack branch_stack;
+		u64 data[64];
+	} branch_stack = {
+		/* 1 branch_entry */
+		.data = {1, -1ULL, 211, 212, 213},
+	};
+	u64 regs[64];
+	const u32 raw_data[] = {0x12345678, 0x0a0b0c0d, 0x11020304, 0x05060708, 0 };
+	const u64 data[] = {0x2211443366558877ULL, 0, 0xaabbccddeeff4321ULL};
+	const u64 aux_data[] = {0xa55a, 0, 0xeeddee, 0x0282028202820282};
+	struct regs_dump user_regs = {
+		.abi	= PERF_SAMPLE_REGS_ABI_64,
+		.mask	= sample_regs,
+		.regs	= regs,
+	};
+	struct regs_dump intr_regs = {
+		.abi	= PERF_SAMPLE_REGS_ABI_64,
+		.mask	= sample_regs,
+		.regs	= regs,
+	};
+	struct perf_sample sample = {
+		.ip		= 101,
+		.pid		= 102,
+		.tid		= 103,
+		.time		= 104,
+		.addr		= 105,
+		.id		= 106,
+		.stream_id	= 107,
+		.period		= 108,
+		.weight		= 109,
+		.cpu		= 110,
+		.raw_size	= sizeof(raw_data),
+		.data_src	= 111,
+		.transaction	= 112,
+		.raw_data	= (void *)raw_data,
+		.callchain	= &callchain.callchain,
+		.no_hw_idx      = false,
+		.branch_stack	= &branch_stack.branch_stack,
+		.user_regs	= &user_regs,
+		.user_stack	= {
+			.size	= sizeof(data),
+			.data	= (void *)data,
+		},
+		.read		= {
+			.time_enabled = 0x030a59d664fca7deULL,
+			.time_running = 0x011b6ae553eb98edULL,
+		},
+		.intr_regs	= &intr_regs,
+		.phys_addr	= 113,
+		.cgroup		= 114,
+		.data_page_size = 115,
+		.code_page_size = 116,
+		.ins_lat	= 117,
+		.weight3	= 118,
+		.aux_sample	= {
+			.size	= sizeof(aux_data),
+			.data	= (void *)aux_data,
+		},
+	};
+	struct sample_read_value values[] = {{1, 5, 0}, {9, 3, 0}, {2, 7, 0}, {6, 4, 1},};
+	struct sample_read_value packed_values[ARRAY_SIZE(values)];
+	struct perf_sample sample_out, sample_out_endian;
+	size_t i, sz, bufsz;
+	int err, ret = -1;
+
+	evsel = evsel__new(&attr);
+	if (!evsel) {
+		pr_debug("evsel__new failed\n");
+		return -1;
+	}
+	perf_sample__init(&sample_out, /*all=*/false);
+	perf_sample__init(&sample_out_endian, /*all=*/false);
+	if (sample_type & PERF_SAMPLE_REGS_USER)
+		evsel->core.attr.sample_regs_user = sample_regs;
+
+	if (sample_type & PERF_SAMPLE_REGS_INTR)
+		evsel->core.attr.sample_regs_intr = sample_regs;
+
+	if (sample_type & PERF_SAMPLE_BRANCH_STACK)
+		evsel->core.attr.branch_sample_type |= PERF_SAMPLE_BRANCH_HW_INDEX;
+
+	for (i = 0; i < sizeof(regs); i++)
+		*(i + (u8 *)regs) = i & 0xfe;
+
+	if (read_format & PERF_FORMAT_GROUP) {
+		size_t vsz = sample_read_value_size(read_format);
+
+		/*
+		 * evsel__parse_sample() points read.group.values at the event
+		 * data, where the entries are packed according to read_format,
+		 * so build the input the same way.  Otherwise the fields
+		 * compared afterwards are just overlapping bytes.
+		 */
+		for (i = 0; i < ARRAY_SIZE(values); i++)
+			memcpy((void *)packed_values + i * vsz, &values[i], vsz);
+
+		sample.read.group.nr     = ARRAY_SIZE(values);
+		sample.read.group.values = packed_values;
+	} else {
+		sample.read.one.value = 0x08789faeb786aa87ULL;
+		sample.read.one.id    = 99;
+		sample.read.one.lost  = 1;
+	}
+
+	sz = perf_event__sample_event_size(&sample, sample_type, read_format,
+					   evsel->core.attr.branch_sample_type);
+	bufsz = sz + 4096; /* Add a bit for overrun checking */
+	event = malloc(bufsz);
+	if (!event) {
+		pr_debug("malloc failed\n");
+		goto out_free;
+	}
+
+	memset(event, 0xff, bufsz);
+	event->header.type = PERF_RECORD_SAMPLE;
+	event->header.misc = 0;
+	event->header.size = sz;
+
+	err = perf_event__synthesize_sample(event, sample_type, read_format,
+					    evsel->core.attr.branch_sample_type, &sample);
+	if (err) {
+		pr_debug("%s failed for sample_type %#"PRIx64", error %d\n",
+			 "perf_event__synthesize_sample", sample_type, err);
+		goto out_free;
+	}
+
+	/* The data does not contain 0xff so we use that to check the size */
+	for (i = bufsz; i > 0; i--) {
+		if (*(i - 1 + (u8 *)event) != 0xff)
+			break;
+	}
+	if (i != sz) {
+		pr_debug("Event size mismatch: actual %zu vs expected %zu\n",
+			 i, sz);
+		goto out_free;
+	}
+
+	evsel->sample_size = __evsel__sample_size(sample_type);
+
+	err = evsel__parse_sample(evsel, event, &sample_out);
+	if (err) {
+		pr_debug("%s failed for sample_type %#"PRIx64", error %d\n",
+			 "evsel__parse_sample", sample_type, err);
+		goto out_free;
+	}
+
+	if (!samples_same(&sample, &sample_out, sample_type, read_format, evsel->needs_swap)) {
+		pr_debug("parsing failed for sample_type %#"PRIx64"\n",
+			 sample_type);
+		goto out_free;
+	}
+
+	if (sample_type == PERF_SAMPLE_BRANCH_STACK) {
+		evsel->needs_swap = true;
+		evsel->sample_size = __evsel__sample_size(sample_type);
+		err = evsel__parse_sample(evsel, event, &sample_out_endian);
+		if (err) {
+			pr_debug("%s failed for sample_type %#"PRIx64", error %d\n",
+				 "evsel__parse_sample", sample_type, err);
+			goto out_free;
+		}
+
+		if (!samples_same(&sample, &sample_out_endian, sample_type,
+				  read_format, evsel->needs_swap)) {
+			pr_debug("parsing failed for sample_type %#"PRIx64"\n",
+				 sample_type);
+			goto out_free;
+		}
+	}
+
+	ret = 0;
+out_free:
+	free(event);
+	perf_sample__exit(&sample_out_endian);
+	perf_sample__exit(&sample_out);
+	evsel__put(evsel);
+	if (ret && read_format)
+		pr_debug("read_format %#"PRIx64"\n", read_format);
+	return ret;
+}
+
+/**
+ * test__sample_parsing - test sample parsing.
+ *
+ * This function implements a test that synthesizes a sample event, parses it
+ * and then checks that the parsed sample matches the original sample.  The test
+ * checks sample format bits separately and together.  If the test passes %0 is
+ * returned, otherwise %-1 is returned.
+ */
+static int test__sample_parsing(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
+{
+	const u64 rf[] = {4, 5, 6, 7, 12, 13, 14, 15, 20, 21, 22, 28, 29, 30, 31};
+	u64 sample_type;
+	u64 sample_regs;
+	size_t i;
+	int err;
+
+	/*
+	 * Fail the test if it has not been updated when new sample format bits
+	 * were added.  Please actually update the test rather than just change
+	 * the condition below.
+	 */
+	if (PERF_SAMPLE_MAX > PERF_SAMPLE_WEIGHT_STRUCT << 1) {
+		pr_debug("sample format has changed, some new PERF_SAMPLE_ bit was introduced - test needs updating\n");
+		return -1;
+	}
+
+	/* Test each sample format bit separately */
+	for (sample_type = 1; sample_type != PERF_SAMPLE_MAX;
+	     sample_type <<= 1) {
+		/* Test read_format variations */
+		if (sample_type == PERF_SAMPLE_READ) {
+			for (i = 0; i < ARRAY_SIZE(rf); i++) {
+				err = do_test(sample_type, 0, rf[i]);
+				if (err)
+					return err;
+			}
+			continue;
+		}
+		sample_regs = 0;
+
+		if (sample_type == PERF_SAMPLE_REGS_USER)
+			sample_regs = 0x3fff;
+
+		if (sample_type == PERF_SAMPLE_REGS_INTR)
+			sample_regs = 0xff0fff;
+
+		err = do_test(sample_type, sample_regs, 0);
+		if (err)
+			return err;
+	}
+
+	/*
+	 * Test all sample format bits together
+	 * Note: PERF_SAMPLE_WEIGHT and PERF_SAMPLE_WEIGHT_STRUCT cannot
+	 *       be set simultaneously.
+	 */
+	sample_type = (PERF_SAMPLE_MAX - 1) & ~PERF_SAMPLE_WEIGHT;
+	sample_regs = 0x3fff; /* shared yb intr and user regs */
+	for (i = 0; i < ARRAY_SIZE(rf); i++) {
+		err = do_test(sample_type, sample_regs, rf[i]);
+		if (err)
+			return err;
+	}
+	sample_type = (PERF_SAMPLE_MAX - 1) & ~PERF_SAMPLE_WEIGHT_STRUCT;
+	for (i = 0; i < ARRAY_SIZE(rf); i++) {
+		err = do_test(sample_type, sample_regs, rf[i]);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+DEFINE_SUITE("Sample parsing", sample_parsing);