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, 298 insertions, 0 deletions

diff --git a/tools/perf/tests/expr.c b/tools/perf/tests/expr.c
new file mode 100644
index 000000000..726cf8d4d
--- /dev/null
+++ b/tools/perf/tests/expr.c
@@ -0,0 +1,298 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "util/cputopo.h"
+#include "util/debug.h"
+#include "util/expr.h"
+#include "util/hashmap.h"
+#include "util/header.h"
+#include "util/smt.h"
+#include "tests.h"
+#include <perf/cpumap.h>
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+#include <string2.h>
+#include <linux/zalloc.h>
+
+static int test_ids_union(void)
+{
+	struct hashmap *ids1, *ids2;
+
+	/* Empty union. */
+	ids1 = ids__new();
+	TEST_ASSERT_VAL("ids__new", ids1);
+	ids2 = ids__new();
+	TEST_ASSERT_VAL("ids__new", ids2);
+
+	ids1 = ids__union(ids1, ids2);
+	TEST_ASSERT_EQUAL("union", (int)hashmap__size(ids1), 0);
+
+	/* Union {foo, bar} against {}. */
+	ids2 = ids__new();
+	TEST_ASSERT_VAL("ids__new", ids2);
+
+	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids1, strdup("foo")), 0);
+	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids1, strdup("bar")), 0);
+
+	ids1 = ids__union(ids1, ids2);
+	TEST_ASSERT_EQUAL("union", (int)hashmap__size(ids1), 2);
+
+	/* Union {foo, bar} against {foo}. */
+	ids2 = ids__new();
+	TEST_ASSERT_VAL("ids__new", ids2);
+	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids2, strdup("foo")), 0);
+
+	ids1 = ids__union(ids1, ids2);
+	TEST_ASSERT_EQUAL("union", (int)hashmap__size(ids1), 2);
+
+	/* Union {foo, bar} against {bar,baz}. */
+	ids2 = ids__new();
+	TEST_ASSERT_VAL("ids__new", ids2);
+	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids2, strdup("bar")), 0);
+	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids2, strdup("baz")), 0);
+
+	ids1 = ids__union(ids1, ids2);
+	TEST_ASSERT_EQUAL("union", (int)hashmap__size(ids1), 3);
+
+	ids__free(ids1);
+
+	return 0;
+}
+
+static int test(struct expr_parse_ctx *ctx, const char *e, double val2)
+{
+	double val;
+
+	if (expr__parse(&val, ctx, e))
+		TEST_ASSERT_VAL("parse test failed", 0);
+	TEST_ASSERT_VAL("unexpected value", val == val2);
+	return 0;
+}
+
+static int test__expr(struct test_suite *t __maybe_unused, int subtest __maybe_unused)
+{
+	struct expr_id_data *val_ptr;
+	const char *p;
+	double val, num_cpus_online, num_cpus, num_cores, num_dies, num_packages;
+	int ret;
+	struct expr_parse_ctx *ctx;
+	char strcmp_cpuid_buf[256];
+	struct perf_cpu cpu = {-1};
+	char *cpuid = get_cpuid_allow_env_override(cpu);
+	char *escaped_cpuid1, *escaped_cpuid2;
+
+	TEST_ASSERT_VAL("get_cpuid", cpuid);
+
+	TEST_ASSERT_EQUAL("ids_union", test_ids_union(), 0);
+
+	ctx = expr__ctx_new();
+	TEST_ASSERT_VAL("expr__ctx_new", ctx);
+	expr__add_id_val(ctx, strdup("FOO"), 1);
+	expr__add_id_val(ctx, strdup("BAR"), 2);
+
+	ret = test(ctx, "1+1", 2);
+	ret |= test(ctx, "FOO+BAR", 3);
+	ret |= test(ctx, "(BAR/2)%2", 1);
+	ret |= test(ctx, "1 - -4",  5);
+	ret |= test(ctx, "(FOO-1)*2 + (BAR/2)%2 - -4",  5);
+	ret |= test(ctx, "1-1 | 1", 1);
+	ret |= test(ctx, "1-1 & 1", 0);
+	ret |= test(ctx, "min(1,2) + 1", 2);
+	ret |= test(ctx, "max(1,2) + 1", 3);
+	ret |= test(ctx, "1+1 if 3*4 else 0", 2);
+	ret |= test(ctx, "100 if 1 else 200 if 1 else 300", 100);
+	ret |= test(ctx, "100 if 0 else 200 if 1 else 300", 200);
+	ret |= test(ctx, "100 if 1 else 200 if 0 else 300", 100);
+	ret |= test(ctx, "100 if 0 else 200 if 0 else 300", 300);
+	ret |= test(ctx, "1.1 + 2.1", 3.2);
+	ret |= test(ctx, ".1 + 2.", 2.1);
+	ret |= test(ctx, "d_ratio(1, 2)", 0.5);
+	ret |= test(ctx, "d_ratio(2.5, 0)", 0);
+	ret |= test(ctx, "1.1 < 2.2", 1);
+	ret |= test(ctx, "2.2 > 1.1", 1);
+	ret |= test(ctx, "1.1 < 1.1", 0);
+	ret |= test(ctx, "2.2 > 2.2", 0);
+	ret |= test(ctx, "2.2 < 1.1", 0);
+	ret |= test(ctx, "1.1 > 2.2", 0);
+	ret |= test(ctx, "1.1e10 < 1.1e100", 1);
+	ret |= test(ctx, "1.1e2 > 1.1e-2", 1);
+
+	if (ret) {
+		expr__ctx_free(ctx);
+		return ret;
+	}
+
+	p = "FOO/0";
+	ret = expr__parse(&val, ctx, p);
+	TEST_ASSERT_VAL("division by zero", ret == 0);
+	TEST_ASSERT_VAL("division by zero", isnan(val));
+
+	p = "BAR/";
+	ret = expr__parse(&val, ctx, p);
+	TEST_ASSERT_VAL("missing operand", ret == -1);
+
+	expr__ctx_clear(ctx);
+	TEST_ASSERT_VAL("find ids",
+			expr__find_ids("FOO + BAR + BAZ + BOZO", "FOO",
+					ctx) == 0);
+	TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 3);
+	TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "BAR", &val_ptr));
+	TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "BAZ", &val_ptr));
+	TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "BOZO", &val_ptr));
+
+	expr__ctx_clear(ctx);
+	ctx->sctx.runtime = 3;
+	TEST_ASSERT_VAL("find ids",
+			expr__find_ids("EVENT1\\,param\\=?@ + EVENT2\\,param\\=?@",
+					NULL, ctx) == 0);
+	TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 2);
+	TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "EVENT1,param=3@", &val_ptr));
+	TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "EVENT2,param=3@", &val_ptr));
+
+	expr__ctx_clear(ctx);
+	TEST_ASSERT_VAL("find ids",
+			expr__find_ids("dash\\-event1 - dash\\-event2",
+				       NULL, ctx) == 0);
+	TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 2);
+	TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "dash-event1", &val_ptr));
+	TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "dash-event2", &val_ptr));
+
+	/* Only EVENT1 or EVENT2 need be measured depending on the value of smt_on. */
+	{
+		bool smton = smt_on();
+		bool corewide = core_wide(/*system_wide=*/false,
+					  /*user_requested_cpus=*/false);
+
+		expr__ctx_clear(ctx);
+		TEST_ASSERT_VAL("find ids",
+				expr__find_ids("EVENT1 if #smt_on else EVENT2",
+					NULL, ctx) == 0);
+		TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 1);
+		TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids,
+							  smton ? "EVENT1" : "EVENT2",
+							  &val_ptr));
+
+		expr__ctx_clear(ctx);
+		TEST_ASSERT_VAL("find ids",
+				expr__find_ids("EVENT1 if #core_wide else EVENT2",
+					NULL, ctx) == 0);
+		TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 1);
+		TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids,
+							  corewide ? "EVENT1" : "EVENT2",
+							  &val_ptr));
+
+	}
+	/* The expression is a constant 1.0 without needing to evaluate EVENT1. */
+	expr__ctx_clear(ctx);
+	TEST_ASSERT_VAL("find ids",
+			expr__find_ids("1.0 if EVENT1 > 100.0 else 1.0",
+			NULL, ctx) == 0);
+	TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 0);
+
+	/* The expression is a constant 0.0 without needing to evaluate EVENT1. */
+	expr__ctx_clear(ctx);
+	TEST_ASSERT_VAL("find ids",
+			expr__find_ids("0 & EVENT1 > 0", NULL, ctx) == 0);
+	TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 0);
+	expr__ctx_clear(ctx);
+	TEST_ASSERT_VAL("find ids",
+			expr__find_ids("EVENT1 > 0 & 0", NULL, ctx) == 0);
+	TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 0);
+	expr__ctx_clear(ctx);
+	TEST_ASSERT_VAL("find ids",
+			expr__find_ids("1 & EVENT1 > 0", NULL, ctx) == 0);
+	TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 1);
+	TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "EVENT1", &val_ptr));
+	expr__ctx_clear(ctx);
+	TEST_ASSERT_VAL("find ids",
+			expr__find_ids("EVENT1 > 0 & 1", NULL, ctx) == 0);
+	TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 1);
+	TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "EVENT1", &val_ptr));
+
+	/* The expression is a constant 1.0 without needing to evaluate EVENT1. */
+	expr__ctx_clear(ctx);
+	TEST_ASSERT_VAL("find ids",
+			expr__find_ids("1 | EVENT1 > 0", NULL, ctx) == 0);
+	TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 0);
+	expr__ctx_clear(ctx);
+	TEST_ASSERT_VAL("find ids",
+			expr__find_ids("EVENT1 > 0 | 1", NULL, ctx) == 0);
+	TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 0);
+	expr__ctx_clear(ctx);
+	TEST_ASSERT_VAL("find ids",
+			expr__find_ids("0 | EVENT1 > 0", NULL, ctx) == 0);
+	TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 1);
+	TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "EVENT1", &val_ptr));
+	expr__ctx_clear(ctx);
+	TEST_ASSERT_VAL("find ids",
+			expr__find_ids("EVENT1 > 0 | 0", NULL, ctx) == 0);
+	TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 1);
+	TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "EVENT1", &val_ptr));
+
+	/* Test toplogy constants appear well ordered. */
+	expr__ctx_clear(ctx);
+	TEST_ASSERT_VAL("#num_cpus_online",
+			expr__parse(&num_cpus_online, ctx, "#num_cpus_online") == 0);
+	TEST_ASSERT_VAL("#num_cpus", expr__parse(&num_cpus, ctx, "#num_cpus") == 0);
+	TEST_ASSERT_VAL("#num_cpus >= #num_cpus_online", num_cpus >= num_cpus_online);
+	TEST_ASSERT_VAL("#num_cores", expr__parse(&num_cores, ctx, "#num_cores") == 0);
+	TEST_ASSERT_VAL("#num_cpus >= #num_cores", num_cpus >= num_cores);
+	TEST_ASSERT_VAL("#num_dies", expr__parse(&num_dies, ctx, "#num_dies") == 0);
+	TEST_ASSERT_VAL("#num_cores >= #num_dies", num_cores >= num_dies);
+	TEST_ASSERT_VAL("#num_packages", expr__parse(&num_packages, ctx, "#num_packages") == 0);
+
+	if (num_dies) // Some platforms do not have CPU die support, for example s390
+		TEST_ASSERT_VAL("#num_dies >= #num_packages", num_dies >= num_packages);
+
+
+	if (expr__parse(&val, ctx, "#system_tsc_freq") == 0) {
+		bool is_intel = strstr(cpuid, "Intel") != NULL;
+
+		if (is_intel)
+			TEST_ASSERT_VAL("#system_tsc_freq > 0", val > 0);
+		else
+			TEST_ASSERT_VAL("#system_tsc_freq == 0", fpclassify(val) == FP_ZERO);
+	} else {
+#if defined(__i386__) || defined(__x86_64__)
+		TEST_ASSERT_VAL("#system_tsc_freq unsupported", 0);
+#endif
+	}
+	/*
+	 * Source count returns the number of events aggregating in a leader
+	 * event including the leader. Check parsing yields an id.
+	 */
+	expr__ctx_clear(ctx);
+	TEST_ASSERT_VAL("source count",
+			expr__find_ids("source_count(EVENT1)",
+			NULL, ctx) == 0);
+	TEST_ASSERT_VAL("source count", hashmap__size(ctx->ids) == 1);
+	TEST_ASSERT_VAL("source count", hashmap__find(ctx->ids, "EVENT1", &val_ptr));
+
+
+	/* Test no cpuid match */
+	ret = test(ctx, "strcmp_cpuid_str(0x0)", 0);
+
+	/*
+	 * Test cpuid match with current cpuid. Special chars have to be
+	 * escaped.
+	 */
+	escaped_cpuid1 = strreplace_chars('-', cpuid, "\\-");
+	free(cpuid);
+	escaped_cpuid2 = strreplace_chars(',', escaped_cpuid1, "\\,");
+	free(escaped_cpuid1);
+	escaped_cpuid1 = strreplace_chars('=', escaped_cpuid2, "\\=");
+	free(escaped_cpuid2);
+	scnprintf(strcmp_cpuid_buf, sizeof(strcmp_cpuid_buf),
+		  "strcmp_cpuid_str(%s)", escaped_cpuid1);
+	free(escaped_cpuid1);
+	ret |= test(ctx, strcmp_cpuid_buf, 1);
+
+	/* has_event returns 1 when an event exists. */
+	expr__add_id_val(ctx, strdup("cycles"), 2);
+	ret |= test(ctx, "has_event(cycles)", 1);
+
+	expr__ctx_free(ctx);
+
+	return ret;
+}
+
+DEFINE_SUITE("Simple expression parser", expr);