xref: /openbmc/linux/kernel/kcsan/kcsan_test.c (revision b8b350af)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * KCSAN test with various race scenarious to test runtime behaviour. Since the
4  * interface with which KCSAN's reports are obtained is via the console, this is
5  * the output we should verify. For each test case checks the presence (or
6  * absence) of generated reports. Relies on 'console' tracepoint to capture
7  * reports as they appear in the kernel log.
8  *
9  * Makes use of KUnit for test organization, and the Torture framework for test
10  * thread control.
11  *
12  * Copyright (C) 2020, Google LLC.
13  * Author: Marco Elver <elver@google.com>
14  */
15 
16 #define pr_fmt(fmt) "kcsan_test: " fmt
17 
18 #include <kunit/test.h>
19 #include <linux/jiffies.h>
20 #include <linux/kcsan-checks.h>
21 #include <linux/kernel.h>
22 #include <linux/sched.h>
23 #include <linux/seqlock.h>
24 #include <linux/spinlock.h>
25 #include <linux/string.h>
26 #include <linux/timer.h>
27 #include <linux/torture.h>
28 #include <linux/tracepoint.h>
29 #include <linux/types.h>
30 #include <trace/events/printk.h>
31 
32 #ifdef CONFIG_CC_HAS_TSAN_COMPOUND_READ_BEFORE_WRITE
33 #define __KCSAN_ACCESS_RW(alt) (KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE)
34 #else
35 #define __KCSAN_ACCESS_RW(alt) (alt)
36 #endif
37 
38 /* Points to current test-case memory access "kernels". */
39 static void (*access_kernels[2])(void);
40 
41 static struct task_struct **threads; /* Lists of threads. */
42 static unsigned long end_time;       /* End time of test. */
43 
44 /* Report as observed from console. */
45 static struct {
46 	spinlock_t lock;
47 	int nlines;
48 	char lines[3][512];
49 } observed = {
50 	.lock = __SPIN_LOCK_UNLOCKED(observed.lock),
51 };
52 
53 /* Setup test checking loop. */
54 static __no_kcsan inline void
55 begin_test_checks(void (*func1)(void), void (*func2)(void))
56 {
57 	kcsan_disable_current();
58 
59 	/*
60 	 * Require at least as long as KCSAN_REPORT_ONCE_IN_MS, to ensure at
61 	 * least one race is reported.
62 	 */
63 	end_time = jiffies + msecs_to_jiffies(CONFIG_KCSAN_REPORT_ONCE_IN_MS + 500);
64 
65 	/* Signal start; release potential initialization of shared data. */
66 	smp_store_release(&access_kernels[0], func1);
67 	smp_store_release(&access_kernels[1], func2);
68 }
69 
70 /* End test checking loop. */
71 static __no_kcsan inline bool
72 end_test_checks(bool stop)
73 {
74 	if (!stop && time_before(jiffies, end_time)) {
75 		/* Continue checking */
76 		might_sleep();
77 		return false;
78 	}
79 
80 	kcsan_enable_current();
81 	return true;
82 }
83 
84 /*
85  * Probe for console output: checks if a race was reported, and obtains observed
86  * lines of interest.
87  */
88 __no_kcsan
89 static void probe_console(void *ignore, const char *buf, size_t len)
90 {
91 	unsigned long flags;
92 	int nlines;
93 
94 	/*
95 	 * Note that KCSAN reports under a global lock, so we do not risk the
96 	 * possibility of having multiple reports interleaved. If that were the
97 	 * case, we'd expect tests to fail.
98 	 */
99 
100 	spin_lock_irqsave(&observed.lock, flags);
101 	nlines = observed.nlines;
102 
103 	if (strnstr(buf, "BUG: KCSAN: ", len) && strnstr(buf, "test_", len)) {
104 		/*
105 		 * KCSAN report and related to the test.
106 		 *
107 		 * The provided @buf is not NUL-terminated; copy no more than
108 		 * @len bytes and let strscpy() add the missing NUL-terminator.
109 		 */
110 		strscpy(observed.lines[0], buf, min(len + 1, sizeof(observed.lines[0])));
111 		nlines = 1;
112 	} else if ((nlines == 1 || nlines == 2) && strnstr(buf, "bytes by", len)) {
113 		strscpy(observed.lines[nlines++], buf, min(len + 1, sizeof(observed.lines[0])));
114 
115 		if (strnstr(buf, "race at unknown origin", len)) {
116 			if (WARN_ON(nlines != 2))
117 				goto out;
118 
119 			/* No second line of interest. */
120 			strcpy(observed.lines[nlines++], "<none>");
121 		}
122 	}
123 
124 out:
125 	WRITE_ONCE(observed.nlines, nlines); /* Publish new nlines. */
126 	spin_unlock_irqrestore(&observed.lock, flags);
127 }
128 
129 /* Check if a report related to the test exists. */
130 __no_kcsan
131 static bool report_available(void)
132 {
133 	return READ_ONCE(observed.nlines) == ARRAY_SIZE(observed.lines);
134 }
135 
136 /* Report information we expect in a report. */
137 struct expect_report {
138 	/* Access information of both accesses. */
139 	struct {
140 		void *fn;    /* Function pointer to expected function of top frame. */
141 		void *addr;  /* Address of access; unchecked if NULL. */
142 		size_t size; /* Size of access; unchecked if @addr is NULL. */
143 		int type;    /* Access type, see KCSAN_ACCESS definitions. */
144 	} access[2];
145 };
146 
147 /* Check observed report matches information in @r. */
148 __no_kcsan
149 static bool report_matches(const struct expect_report *r)
150 {
151 	const bool is_assert = (r->access[0].type | r->access[1].type) & KCSAN_ACCESS_ASSERT;
152 	bool ret = false;
153 	unsigned long flags;
154 	typeof(observed.lines) expect;
155 	const char *end;
156 	char *cur;
157 	int i;
158 
159 	/* Doubled-checked locking. */
160 	if (!report_available())
161 		return false;
162 
163 	/* Generate expected report contents. */
164 
165 	/* Title */
166 	cur = expect[0];
167 	end = &expect[0][sizeof(expect[0]) - 1];
168 	cur += scnprintf(cur, end - cur, "BUG: KCSAN: %s in ",
169 			 is_assert ? "assert: race" : "data-race");
170 	if (r->access[1].fn) {
171 		char tmp[2][64];
172 		int cmp;
173 
174 		/* Expect lexographically sorted function names in title. */
175 		scnprintf(tmp[0], sizeof(tmp[0]), "%pS", r->access[0].fn);
176 		scnprintf(tmp[1], sizeof(tmp[1]), "%pS", r->access[1].fn);
177 		cmp = strcmp(tmp[0], tmp[1]);
178 		cur += scnprintf(cur, end - cur, "%ps / %ps",
179 				 cmp < 0 ? r->access[0].fn : r->access[1].fn,
180 				 cmp < 0 ? r->access[1].fn : r->access[0].fn);
181 	} else {
182 		scnprintf(cur, end - cur, "%pS", r->access[0].fn);
183 		/* The exact offset won't match, remove it. */
184 		cur = strchr(expect[0], '+');
185 		if (cur)
186 			*cur = '\0';
187 	}
188 
189 	/* Access 1 */
190 	cur = expect[1];
191 	end = &expect[1][sizeof(expect[1]) - 1];
192 	if (!r->access[1].fn)
193 		cur += scnprintf(cur, end - cur, "race at unknown origin, with ");
194 
195 	/* Access 1 & 2 */
196 	for (i = 0; i < 2; ++i) {
197 		const int ty = r->access[i].type;
198 		const char *const access_type =
199 			(ty & KCSAN_ACCESS_ASSERT) ?
200 				      ((ty & KCSAN_ACCESS_WRITE) ?
201 					       "assert no accesses" :
202 					       "assert no writes") :
203 				      ((ty & KCSAN_ACCESS_WRITE) ?
204 					       ((ty & KCSAN_ACCESS_COMPOUND) ?
205 							"read-write" :
206 							"write") :
207 					       "read");
208 		const char *const access_type_aux =
209 			(ty & KCSAN_ACCESS_ATOMIC) ?
210 				      " (marked)" :
211 				      ((ty & KCSAN_ACCESS_SCOPED) ? " (scoped)" : "");
212 
213 		if (i == 1) {
214 			/* Access 2 */
215 			cur = expect[2];
216 			end = &expect[2][sizeof(expect[2]) - 1];
217 
218 			if (!r->access[1].fn) {
219 				/* Dummy string if no second access is available. */
220 				strcpy(cur, "<none>");
221 				break;
222 			}
223 		}
224 
225 		cur += scnprintf(cur, end - cur, "%s%s to ", access_type,
226 				 access_type_aux);
227 
228 		if (r->access[i].addr) /* Address is optional. */
229 			cur += scnprintf(cur, end - cur, "0x%px of %zu bytes",
230 					 r->access[i].addr, r->access[i].size);
231 	}
232 
233 	spin_lock_irqsave(&observed.lock, flags);
234 	if (!report_available())
235 		goto out; /* A new report is being captured. */
236 
237 	/* Finally match expected output to what we actually observed. */
238 	ret = strstr(observed.lines[0], expect[0]) &&
239 	      /* Access info may appear in any order. */
240 	      ((strstr(observed.lines[1], expect[1]) &&
241 		strstr(observed.lines[2], expect[2])) ||
242 	       (strstr(observed.lines[1], expect[2]) &&
243 		strstr(observed.lines[2], expect[1])));
244 out:
245 	spin_unlock_irqrestore(&observed.lock, flags);
246 	return ret;
247 }
248 
249 /* ===== Test kernels ===== */
250 
251 static long test_sink;
252 static long test_var;
253 /* @test_array should be large enough to fall into multiple watchpoint slots. */
254 static long test_array[3 * PAGE_SIZE / sizeof(long)];
255 static struct {
256 	long val[8];
257 } test_struct;
258 static DEFINE_SEQLOCK(test_seqlock);
259 
260 /*
261  * Helper to avoid compiler optimizing out reads, and to generate source values
262  * for writes.
263  */
264 __no_kcsan
265 static noinline void sink_value(long v) { WRITE_ONCE(test_sink, v); }
266 
267 static noinline void test_kernel_read(void) { sink_value(test_var); }
268 
269 static noinline void test_kernel_write(void)
270 {
271 	test_var = READ_ONCE_NOCHECK(test_sink) + 1;
272 }
273 
274 static noinline void test_kernel_write_nochange(void) { test_var = 42; }
275 
276 /* Suffixed by value-change exception filter. */
277 static noinline void test_kernel_write_nochange_rcu(void) { test_var = 42; }
278 
279 static noinline void test_kernel_read_atomic(void)
280 {
281 	sink_value(READ_ONCE(test_var));
282 }
283 
284 static noinline void test_kernel_write_atomic(void)
285 {
286 	WRITE_ONCE(test_var, READ_ONCE_NOCHECK(test_sink) + 1);
287 }
288 
289 static noinline void test_kernel_atomic_rmw(void)
290 {
291 	/* Use builtin, so we can set up the "bad" atomic/non-atomic scenario. */
292 	__atomic_fetch_add(&test_var, 1, __ATOMIC_RELAXED);
293 }
294 
295 __no_kcsan
296 static noinline void test_kernel_write_uninstrumented(void) { test_var++; }
297 
298 static noinline void test_kernel_data_race(void) { data_race(test_var++); }
299 
300 static noinline void test_kernel_assert_writer(void)
301 {
302 	ASSERT_EXCLUSIVE_WRITER(test_var);
303 }
304 
305 static noinline void test_kernel_assert_access(void)
306 {
307 	ASSERT_EXCLUSIVE_ACCESS(test_var);
308 }
309 
310 #define TEST_CHANGE_BITS 0xff00ff00
311 
312 static noinline void test_kernel_change_bits(void)
313 {
314 	if (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) {
315 		/*
316 		 * Avoid race of unknown origin for this test, just pretend they
317 		 * are atomic.
318 		 */
319 		kcsan_nestable_atomic_begin();
320 		test_var ^= TEST_CHANGE_BITS;
321 		kcsan_nestable_atomic_end();
322 	} else
323 		WRITE_ONCE(test_var, READ_ONCE(test_var) ^ TEST_CHANGE_BITS);
324 }
325 
326 static noinline void test_kernel_assert_bits_change(void)
327 {
328 	ASSERT_EXCLUSIVE_BITS(test_var, TEST_CHANGE_BITS);
329 }
330 
331 static noinline void test_kernel_assert_bits_nochange(void)
332 {
333 	ASSERT_EXCLUSIVE_BITS(test_var, ~TEST_CHANGE_BITS);
334 }
335 
336 /* To check that scoped assertions do trigger anywhere in scope. */
337 static noinline void test_enter_scope(void)
338 {
339 	int x = 0;
340 
341 	/* Unrelated accesses to scoped assert. */
342 	READ_ONCE(test_sink);
343 	kcsan_check_read(&x, sizeof(x));
344 }
345 
346 static noinline void test_kernel_assert_writer_scoped(void)
347 {
348 	ASSERT_EXCLUSIVE_WRITER_SCOPED(test_var);
349 	test_enter_scope();
350 }
351 
352 static noinline void test_kernel_assert_access_scoped(void)
353 {
354 	ASSERT_EXCLUSIVE_ACCESS_SCOPED(test_var);
355 	test_enter_scope();
356 }
357 
358 static noinline void test_kernel_rmw_array(void)
359 {
360 	int i;
361 
362 	for (i = 0; i < ARRAY_SIZE(test_array); ++i)
363 		test_array[i]++;
364 }
365 
366 static noinline void test_kernel_write_struct(void)
367 {
368 	kcsan_check_write(&test_struct, sizeof(test_struct));
369 	kcsan_disable_current();
370 	test_struct.val[3]++; /* induce value change */
371 	kcsan_enable_current();
372 }
373 
374 static noinline void test_kernel_write_struct_part(void)
375 {
376 	test_struct.val[3] = 42;
377 }
378 
379 static noinline void test_kernel_read_struct_zero_size(void)
380 {
381 	kcsan_check_read(&test_struct.val[3], 0);
382 }
383 
384 static noinline void test_kernel_jiffies_reader(void)
385 {
386 	sink_value((long)jiffies);
387 }
388 
389 static noinline void test_kernel_seqlock_reader(void)
390 {
391 	unsigned int seq;
392 
393 	do {
394 		seq = read_seqbegin(&test_seqlock);
395 		sink_value(test_var);
396 	} while (read_seqretry(&test_seqlock, seq));
397 }
398 
399 static noinline void test_kernel_seqlock_writer(void)
400 {
401 	unsigned long flags;
402 
403 	write_seqlock_irqsave(&test_seqlock, flags);
404 	test_var++;
405 	write_sequnlock_irqrestore(&test_seqlock, flags);
406 }
407 
408 static noinline void test_kernel_atomic_builtins(void)
409 {
410 	/*
411 	 * Generate concurrent accesses, expecting no reports, ensuring KCSAN
412 	 * treats builtin atomics as actually atomic.
413 	 */
414 	__atomic_load_n(&test_var, __ATOMIC_RELAXED);
415 }
416 
417 static noinline void test_kernel_xor_1bit(void)
418 {
419 	/* Do not report data races between the read-writes. */
420 	kcsan_nestable_atomic_begin();
421 	test_var ^= 0x10000;
422 	kcsan_nestable_atomic_end();
423 }
424 
425 /* ===== Test cases ===== */
426 
427 /* Simple test with normal data race. */
428 __no_kcsan
429 static void test_basic(struct kunit *test)
430 {
431 	const struct expect_report expect = {
432 		.access = {
433 			{ test_kernel_write, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
434 			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
435 		},
436 	};
437 	static const struct expect_report never = {
438 		.access = {
439 			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
440 			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
441 		},
442 	};
443 	bool match_expect = false;
444 	bool match_never = false;
445 
446 	begin_test_checks(test_kernel_write, test_kernel_read);
447 	do {
448 		match_expect |= report_matches(&expect);
449 		match_never = report_matches(&never);
450 	} while (!end_test_checks(match_never));
451 	KUNIT_EXPECT_TRUE(test, match_expect);
452 	KUNIT_EXPECT_FALSE(test, match_never);
453 }
454 
455 /*
456  * Stress KCSAN with lots of concurrent races on different addresses until
457  * timeout.
458  */
459 __no_kcsan
460 static void test_concurrent_races(struct kunit *test)
461 {
462 	const struct expect_report expect = {
463 		.access = {
464 			/* NULL will match any address. */
465 			{ test_kernel_rmw_array, NULL, 0, __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) },
466 			{ test_kernel_rmw_array, NULL, 0, __KCSAN_ACCESS_RW(0) },
467 		},
468 	};
469 	static const struct expect_report never = {
470 		.access = {
471 			{ test_kernel_rmw_array, NULL, 0, 0 },
472 			{ test_kernel_rmw_array, NULL, 0, 0 },
473 		},
474 	};
475 	bool match_expect = false;
476 	bool match_never = false;
477 
478 	begin_test_checks(test_kernel_rmw_array, test_kernel_rmw_array);
479 	do {
480 		match_expect |= report_matches(&expect);
481 		match_never |= report_matches(&never);
482 	} while (!end_test_checks(false));
483 	KUNIT_EXPECT_TRUE(test, match_expect); /* Sanity check matches exist. */
484 	KUNIT_EXPECT_FALSE(test, match_never);
485 }
486 
487 /* Test the KCSAN_REPORT_VALUE_CHANGE_ONLY option. */
488 __no_kcsan
489 static void test_novalue_change(struct kunit *test)
490 {
491 	const struct expect_report expect = {
492 		.access = {
493 			{ test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
494 			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
495 		},
496 	};
497 	bool match_expect = false;
498 
499 	begin_test_checks(test_kernel_write_nochange, test_kernel_read);
500 	do {
501 		match_expect = report_matches(&expect);
502 	} while (!end_test_checks(match_expect));
503 	if (IS_ENABLED(CONFIG_KCSAN_REPORT_VALUE_CHANGE_ONLY))
504 		KUNIT_EXPECT_FALSE(test, match_expect);
505 	else
506 		KUNIT_EXPECT_TRUE(test, match_expect);
507 }
508 
509 /*
510  * Test that the rules where the KCSAN_REPORT_VALUE_CHANGE_ONLY option should
511  * never apply work.
512  */
513 __no_kcsan
514 static void test_novalue_change_exception(struct kunit *test)
515 {
516 	const struct expect_report expect = {
517 		.access = {
518 			{ test_kernel_write_nochange_rcu, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
519 			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
520 		},
521 	};
522 	bool match_expect = false;
523 
524 	begin_test_checks(test_kernel_write_nochange_rcu, test_kernel_read);
525 	do {
526 		match_expect = report_matches(&expect);
527 	} while (!end_test_checks(match_expect));
528 	KUNIT_EXPECT_TRUE(test, match_expect);
529 }
530 
531 /* Test that data races of unknown origin are reported. */
532 __no_kcsan
533 static void test_unknown_origin(struct kunit *test)
534 {
535 	const struct expect_report expect = {
536 		.access = {
537 			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
538 			{ NULL },
539 		},
540 	};
541 	bool match_expect = false;
542 
543 	begin_test_checks(test_kernel_write_uninstrumented, test_kernel_read);
544 	do {
545 		match_expect = report_matches(&expect);
546 	} while (!end_test_checks(match_expect));
547 	if (IS_ENABLED(CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN))
548 		KUNIT_EXPECT_TRUE(test, match_expect);
549 	else
550 		KUNIT_EXPECT_FALSE(test, match_expect);
551 }
552 
553 /* Test KCSAN_ASSUME_PLAIN_WRITES_ATOMIC if it is selected. */
554 __no_kcsan
555 static void test_write_write_assume_atomic(struct kunit *test)
556 {
557 	const struct expect_report expect = {
558 		.access = {
559 			{ test_kernel_write, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
560 			{ test_kernel_write, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
561 		},
562 	};
563 	bool match_expect = false;
564 
565 	begin_test_checks(test_kernel_write, test_kernel_write);
566 	do {
567 		sink_value(READ_ONCE(test_var)); /* induce value-change */
568 		match_expect = report_matches(&expect);
569 	} while (!end_test_checks(match_expect));
570 	if (IS_ENABLED(CONFIG_KCSAN_ASSUME_PLAIN_WRITES_ATOMIC))
571 		KUNIT_EXPECT_FALSE(test, match_expect);
572 	else
573 		KUNIT_EXPECT_TRUE(test, match_expect);
574 }
575 
576 /*
577  * Test that data races with writes larger than word-size are always reported,
578  * even if KCSAN_ASSUME_PLAIN_WRITES_ATOMIC is selected.
579  */
580 __no_kcsan
581 static void test_write_write_struct(struct kunit *test)
582 {
583 	const struct expect_report expect = {
584 		.access = {
585 			{ test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
586 			{ test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
587 		},
588 	};
589 	bool match_expect = false;
590 
591 	begin_test_checks(test_kernel_write_struct, test_kernel_write_struct);
592 	do {
593 		match_expect = report_matches(&expect);
594 	} while (!end_test_checks(match_expect));
595 	KUNIT_EXPECT_TRUE(test, match_expect);
596 }
597 
598 /*
599  * Test that data races where only one write is larger than word-size are always
600  * reported, even if KCSAN_ASSUME_PLAIN_WRITES_ATOMIC is selected.
601  */
602 __no_kcsan
603 static void test_write_write_struct_part(struct kunit *test)
604 {
605 	const struct expect_report expect = {
606 		.access = {
607 			{ test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
608 			{ test_kernel_write_struct_part, &test_struct.val[3], sizeof(test_struct.val[3]), KCSAN_ACCESS_WRITE },
609 		},
610 	};
611 	bool match_expect = false;
612 
613 	begin_test_checks(test_kernel_write_struct, test_kernel_write_struct_part);
614 	do {
615 		match_expect = report_matches(&expect);
616 	} while (!end_test_checks(match_expect));
617 	KUNIT_EXPECT_TRUE(test, match_expect);
618 }
619 
620 /* Test that races with atomic accesses never result in reports. */
621 __no_kcsan
622 static void test_read_atomic_write_atomic(struct kunit *test)
623 {
624 	bool match_never = false;
625 
626 	begin_test_checks(test_kernel_read_atomic, test_kernel_write_atomic);
627 	do {
628 		match_never = report_available();
629 	} while (!end_test_checks(match_never));
630 	KUNIT_EXPECT_FALSE(test, match_never);
631 }
632 
633 /* Test that a race with an atomic and plain access result in reports. */
634 __no_kcsan
635 static void test_read_plain_atomic_write(struct kunit *test)
636 {
637 	const struct expect_report expect = {
638 		.access = {
639 			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
640 			{ test_kernel_write_atomic, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC },
641 		},
642 	};
643 	bool match_expect = false;
644 
645 	if (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS))
646 		return;
647 
648 	begin_test_checks(test_kernel_read, test_kernel_write_atomic);
649 	do {
650 		match_expect = report_matches(&expect);
651 	} while (!end_test_checks(match_expect));
652 	KUNIT_EXPECT_TRUE(test, match_expect);
653 }
654 
655 /* Test that atomic RMWs generate correct report. */
656 __no_kcsan
657 static void test_read_plain_atomic_rmw(struct kunit *test)
658 {
659 	const struct expect_report expect = {
660 		.access = {
661 			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
662 			{ test_kernel_atomic_rmw, &test_var, sizeof(test_var),
663 				KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC },
664 		},
665 	};
666 	bool match_expect = false;
667 
668 	if (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS))
669 		return;
670 
671 	begin_test_checks(test_kernel_read, test_kernel_atomic_rmw);
672 	do {
673 		match_expect = report_matches(&expect);
674 	} while (!end_test_checks(match_expect));
675 	KUNIT_EXPECT_TRUE(test, match_expect);
676 }
677 
678 /* Zero-sized accesses should never cause data race reports. */
679 __no_kcsan
680 static void test_zero_size_access(struct kunit *test)
681 {
682 	const struct expect_report expect = {
683 		.access = {
684 			{ test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
685 			{ test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
686 		},
687 	};
688 	const struct expect_report never = {
689 		.access = {
690 			{ test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
691 			{ test_kernel_read_struct_zero_size, &test_struct.val[3], 0, 0 },
692 		},
693 	};
694 	bool match_expect = false;
695 	bool match_never = false;
696 
697 	begin_test_checks(test_kernel_write_struct, test_kernel_read_struct_zero_size);
698 	do {
699 		match_expect |= report_matches(&expect);
700 		match_never = report_matches(&never);
701 	} while (!end_test_checks(match_never));
702 	KUNIT_EXPECT_TRUE(test, match_expect); /* Sanity check. */
703 	KUNIT_EXPECT_FALSE(test, match_never);
704 }
705 
706 /* Test the data_race() macro. */
707 __no_kcsan
708 static void test_data_race(struct kunit *test)
709 {
710 	bool match_never = false;
711 
712 	begin_test_checks(test_kernel_data_race, test_kernel_data_race);
713 	do {
714 		match_never = report_available();
715 	} while (!end_test_checks(match_never));
716 	KUNIT_EXPECT_FALSE(test, match_never);
717 }
718 
719 __no_kcsan
720 static void test_assert_exclusive_writer(struct kunit *test)
721 {
722 	const struct expect_report expect = {
723 		.access = {
724 			{ test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
725 			{ test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
726 		},
727 	};
728 	bool match_expect = false;
729 
730 	begin_test_checks(test_kernel_assert_writer, test_kernel_write_nochange);
731 	do {
732 		match_expect = report_matches(&expect);
733 	} while (!end_test_checks(match_expect));
734 	KUNIT_EXPECT_TRUE(test, match_expect);
735 }
736 
737 __no_kcsan
738 static void test_assert_exclusive_access(struct kunit *test)
739 {
740 	const struct expect_report expect = {
741 		.access = {
742 			{ test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE },
743 			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
744 		},
745 	};
746 	bool match_expect = false;
747 
748 	begin_test_checks(test_kernel_assert_access, test_kernel_read);
749 	do {
750 		match_expect = report_matches(&expect);
751 	} while (!end_test_checks(match_expect));
752 	KUNIT_EXPECT_TRUE(test, match_expect);
753 }
754 
755 __no_kcsan
756 static void test_assert_exclusive_access_writer(struct kunit *test)
757 {
758 	const struct expect_report expect_access_writer = {
759 		.access = {
760 			{ test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE },
761 			{ test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
762 		},
763 	};
764 	const struct expect_report expect_access_access = {
765 		.access = {
766 			{ test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE },
767 			{ test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE },
768 		},
769 	};
770 	const struct expect_report never = {
771 		.access = {
772 			{ test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
773 			{ test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
774 		},
775 	};
776 	bool match_expect_access_writer = false;
777 	bool match_expect_access_access = false;
778 	bool match_never = false;
779 
780 	begin_test_checks(test_kernel_assert_access, test_kernel_assert_writer);
781 	do {
782 		match_expect_access_writer |= report_matches(&expect_access_writer);
783 		match_expect_access_access |= report_matches(&expect_access_access);
784 		match_never |= report_matches(&never);
785 	} while (!end_test_checks(match_never));
786 	KUNIT_EXPECT_TRUE(test, match_expect_access_writer);
787 	KUNIT_EXPECT_TRUE(test, match_expect_access_access);
788 	KUNIT_EXPECT_FALSE(test, match_never);
789 }
790 
791 __no_kcsan
792 static void test_assert_exclusive_bits_change(struct kunit *test)
793 {
794 	const struct expect_report expect = {
795 		.access = {
796 			{ test_kernel_assert_bits_change, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
797 			{ test_kernel_change_bits, &test_var, sizeof(test_var),
798 				KCSAN_ACCESS_WRITE | (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS) ? 0 : KCSAN_ACCESS_ATOMIC) },
799 		},
800 	};
801 	bool match_expect = false;
802 
803 	begin_test_checks(test_kernel_assert_bits_change, test_kernel_change_bits);
804 	do {
805 		match_expect = report_matches(&expect);
806 	} while (!end_test_checks(match_expect));
807 	KUNIT_EXPECT_TRUE(test, match_expect);
808 }
809 
810 __no_kcsan
811 static void test_assert_exclusive_bits_nochange(struct kunit *test)
812 {
813 	bool match_never = false;
814 
815 	begin_test_checks(test_kernel_assert_bits_nochange, test_kernel_change_bits);
816 	do {
817 		match_never = report_available();
818 	} while (!end_test_checks(match_never));
819 	KUNIT_EXPECT_FALSE(test, match_never);
820 }
821 
822 __no_kcsan
823 static void test_assert_exclusive_writer_scoped(struct kunit *test)
824 {
825 	const struct expect_report expect_start = {
826 		.access = {
827 			{ test_kernel_assert_writer_scoped, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_SCOPED },
828 			{ test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
829 		},
830 	};
831 	const struct expect_report expect_anywhere = {
832 		.access = {
833 			{ test_enter_scope, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_SCOPED },
834 			{ test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
835 		},
836 	};
837 	bool match_expect_start = false;
838 	bool match_expect_anywhere = false;
839 
840 	begin_test_checks(test_kernel_assert_writer_scoped, test_kernel_write_nochange);
841 	do {
842 		match_expect_start |= report_matches(&expect_start);
843 		match_expect_anywhere |= report_matches(&expect_anywhere);
844 	} while (!end_test_checks(match_expect_start && match_expect_anywhere));
845 	KUNIT_EXPECT_TRUE(test, match_expect_start);
846 	KUNIT_EXPECT_TRUE(test, match_expect_anywhere);
847 }
848 
849 __no_kcsan
850 static void test_assert_exclusive_access_scoped(struct kunit *test)
851 {
852 	const struct expect_report expect_start1 = {
853 		.access = {
854 			{ test_kernel_assert_access_scoped, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_SCOPED },
855 			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
856 		},
857 	};
858 	const struct expect_report expect_start2 = {
859 		.access = { expect_start1.access[0], expect_start1.access[0] },
860 	};
861 	const struct expect_report expect_inscope = {
862 		.access = {
863 			{ test_enter_scope, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_SCOPED },
864 			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
865 		},
866 	};
867 	bool match_expect_start = false;
868 	bool match_expect_inscope = false;
869 
870 	begin_test_checks(test_kernel_assert_access_scoped, test_kernel_read);
871 	end_time += msecs_to_jiffies(1000); /* This test requires a bit more time. */
872 	do {
873 		match_expect_start |= report_matches(&expect_start1) || report_matches(&expect_start2);
874 		match_expect_inscope |= report_matches(&expect_inscope);
875 	} while (!end_test_checks(match_expect_start && match_expect_inscope));
876 	KUNIT_EXPECT_TRUE(test, match_expect_start);
877 	KUNIT_EXPECT_TRUE(test, match_expect_inscope);
878 }
879 
880 /*
881  * jiffies is special (declared to be volatile) and its accesses are typically
882  * not marked; this test ensures that the compiler nor KCSAN gets confused about
883  * jiffies's declaration on different architectures.
884  */
885 __no_kcsan
886 static void test_jiffies_noreport(struct kunit *test)
887 {
888 	bool match_never = false;
889 
890 	begin_test_checks(test_kernel_jiffies_reader, test_kernel_jiffies_reader);
891 	do {
892 		match_never = report_available();
893 	} while (!end_test_checks(match_never));
894 	KUNIT_EXPECT_FALSE(test, match_never);
895 }
896 
897 /* Test that racing accesses in seqlock critical sections are not reported. */
898 __no_kcsan
899 static void test_seqlock_noreport(struct kunit *test)
900 {
901 	bool match_never = false;
902 
903 	begin_test_checks(test_kernel_seqlock_reader, test_kernel_seqlock_writer);
904 	do {
905 		match_never = report_available();
906 	} while (!end_test_checks(match_never));
907 	KUNIT_EXPECT_FALSE(test, match_never);
908 }
909 
910 /*
911  * Test atomic builtins work and required instrumentation functions exist. We
912  * also test that KCSAN understands they're atomic by racing with them via
913  * test_kernel_atomic_builtins(), and expect no reports.
914  *
915  * The atomic builtins _SHOULD NOT_ be used in normal kernel code!
916  */
917 static void test_atomic_builtins(struct kunit *test)
918 {
919 	bool match_never = false;
920 
921 	begin_test_checks(test_kernel_atomic_builtins, test_kernel_atomic_builtins);
922 	do {
923 		long tmp;
924 
925 		kcsan_enable_current();
926 
927 		__atomic_store_n(&test_var, 42L, __ATOMIC_RELAXED);
928 		KUNIT_EXPECT_EQ(test, 42L, __atomic_load_n(&test_var, __ATOMIC_RELAXED));
929 
930 		KUNIT_EXPECT_EQ(test, 42L, __atomic_exchange_n(&test_var, 20, __ATOMIC_RELAXED));
931 		KUNIT_EXPECT_EQ(test, 20L, test_var);
932 
933 		tmp = 20L;
934 		KUNIT_EXPECT_TRUE(test, __atomic_compare_exchange_n(&test_var, &tmp, 30L,
935 								    0, __ATOMIC_RELAXED,
936 								    __ATOMIC_RELAXED));
937 		KUNIT_EXPECT_EQ(test, tmp, 20L);
938 		KUNIT_EXPECT_EQ(test, test_var, 30L);
939 		KUNIT_EXPECT_FALSE(test, __atomic_compare_exchange_n(&test_var, &tmp, 40L,
940 								     1, __ATOMIC_RELAXED,
941 								     __ATOMIC_RELAXED));
942 		KUNIT_EXPECT_EQ(test, tmp, 30L);
943 		KUNIT_EXPECT_EQ(test, test_var, 30L);
944 
945 		KUNIT_EXPECT_EQ(test, 30L, __atomic_fetch_add(&test_var, 1, __ATOMIC_RELAXED));
946 		KUNIT_EXPECT_EQ(test, 31L, __atomic_fetch_sub(&test_var, 1, __ATOMIC_RELAXED));
947 		KUNIT_EXPECT_EQ(test, 30L, __atomic_fetch_and(&test_var, 0xf, __ATOMIC_RELAXED));
948 		KUNIT_EXPECT_EQ(test, 14L, __atomic_fetch_xor(&test_var, 0xf, __ATOMIC_RELAXED));
949 		KUNIT_EXPECT_EQ(test, 1L, __atomic_fetch_or(&test_var, 0xf0, __ATOMIC_RELAXED));
950 		KUNIT_EXPECT_EQ(test, 241L, __atomic_fetch_nand(&test_var, 0xf, __ATOMIC_RELAXED));
951 		KUNIT_EXPECT_EQ(test, -2L, test_var);
952 
953 		__atomic_thread_fence(__ATOMIC_SEQ_CST);
954 		__atomic_signal_fence(__ATOMIC_SEQ_CST);
955 
956 		kcsan_disable_current();
957 
958 		match_never = report_available();
959 	} while (!end_test_checks(match_never));
960 	KUNIT_EXPECT_FALSE(test, match_never);
961 }
962 
963 __no_kcsan
964 static void test_1bit_value_change(struct kunit *test)
965 {
966 	const struct expect_report expect = {
967 		.access = {
968 			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
969 			{ test_kernel_xor_1bit, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) },
970 		},
971 	};
972 	bool match = false;
973 
974 	begin_test_checks(test_kernel_read, test_kernel_xor_1bit);
975 	do {
976 		match = IS_ENABLED(CONFIG_KCSAN_PERMISSIVE)
977 				? report_available()
978 				: report_matches(&expect);
979 	} while (!end_test_checks(match));
980 	if (IS_ENABLED(CONFIG_KCSAN_PERMISSIVE))
981 		KUNIT_EXPECT_FALSE(test, match);
982 	else
983 		KUNIT_EXPECT_TRUE(test, match);
984 }
985 
986 /*
987  * Generate thread counts for all test cases. Values generated are in interval
988  * [2, 5] followed by exponentially increasing thread counts from 8 to 32.
989  *
990  * The thread counts are chosen to cover potentially interesting boundaries and
991  * corner cases (2 to 5), and then stress the system with larger counts.
992  */
993 static const void *nthreads_gen_params(const void *prev, char *desc)
994 {
995 	long nthreads = (long)prev;
996 
997 	if (nthreads < 0 || nthreads >= 32)
998 		nthreads = 0; /* stop */
999 	else if (!nthreads)
1000 		nthreads = 2; /* initial value */
1001 	else if (nthreads < 5)
1002 		nthreads++;
1003 	else if (nthreads == 5)
1004 		nthreads = 8;
1005 	else
1006 		nthreads *= 2;
1007 
1008 	if (!IS_ENABLED(CONFIG_PREEMPT) || !IS_ENABLED(CONFIG_KCSAN_INTERRUPT_WATCHER)) {
1009 		/*
1010 		 * Without any preemption, keep 2 CPUs free for other tasks, one
1011 		 * of which is the main test case function checking for
1012 		 * completion or failure.
1013 		 */
1014 		const long min_unused_cpus = IS_ENABLED(CONFIG_PREEMPT_NONE) ? 2 : 0;
1015 		const long min_required_cpus = 2 + min_unused_cpus;
1016 
1017 		if (num_online_cpus() < min_required_cpus) {
1018 			pr_err_once("Too few online CPUs (%u < %ld) for test\n",
1019 				    num_online_cpus(), min_required_cpus);
1020 			nthreads = 0;
1021 		} else if (nthreads >= num_online_cpus() - min_unused_cpus) {
1022 			/* Use negative value to indicate last param. */
1023 			nthreads = -(num_online_cpus() - min_unused_cpus);
1024 			pr_warn_once("Limiting number of threads to %ld (only %d online CPUs)\n",
1025 				     -nthreads, num_online_cpus());
1026 		}
1027 	}
1028 
1029 	snprintf(desc, KUNIT_PARAM_DESC_SIZE, "threads=%ld", abs(nthreads));
1030 	return (void *)nthreads;
1031 }
1032 
1033 #define KCSAN_KUNIT_CASE(test_name) KUNIT_CASE_PARAM(test_name, nthreads_gen_params)
1034 static struct kunit_case kcsan_test_cases[] = {
1035 	KCSAN_KUNIT_CASE(test_basic),
1036 	KCSAN_KUNIT_CASE(test_concurrent_races),
1037 	KCSAN_KUNIT_CASE(test_novalue_change),
1038 	KCSAN_KUNIT_CASE(test_novalue_change_exception),
1039 	KCSAN_KUNIT_CASE(test_unknown_origin),
1040 	KCSAN_KUNIT_CASE(test_write_write_assume_atomic),
1041 	KCSAN_KUNIT_CASE(test_write_write_struct),
1042 	KCSAN_KUNIT_CASE(test_write_write_struct_part),
1043 	KCSAN_KUNIT_CASE(test_read_atomic_write_atomic),
1044 	KCSAN_KUNIT_CASE(test_read_plain_atomic_write),
1045 	KCSAN_KUNIT_CASE(test_read_plain_atomic_rmw),
1046 	KCSAN_KUNIT_CASE(test_zero_size_access),
1047 	KCSAN_KUNIT_CASE(test_data_race),
1048 	KCSAN_KUNIT_CASE(test_assert_exclusive_writer),
1049 	KCSAN_KUNIT_CASE(test_assert_exclusive_access),
1050 	KCSAN_KUNIT_CASE(test_assert_exclusive_access_writer),
1051 	KCSAN_KUNIT_CASE(test_assert_exclusive_bits_change),
1052 	KCSAN_KUNIT_CASE(test_assert_exclusive_bits_nochange),
1053 	KCSAN_KUNIT_CASE(test_assert_exclusive_writer_scoped),
1054 	KCSAN_KUNIT_CASE(test_assert_exclusive_access_scoped),
1055 	KCSAN_KUNIT_CASE(test_jiffies_noreport),
1056 	KCSAN_KUNIT_CASE(test_seqlock_noreport),
1057 	KCSAN_KUNIT_CASE(test_atomic_builtins),
1058 	KCSAN_KUNIT_CASE(test_1bit_value_change),
1059 	{},
1060 };
1061 
1062 /* ===== End test cases ===== */
1063 
1064 /* Concurrent accesses from interrupts. */
1065 __no_kcsan
1066 static void access_thread_timer(struct timer_list *timer)
1067 {
1068 	static atomic_t cnt = ATOMIC_INIT(0);
1069 	unsigned int idx;
1070 	void (*func)(void);
1071 
1072 	idx = (unsigned int)atomic_inc_return(&cnt) % ARRAY_SIZE(access_kernels);
1073 	/* Acquire potential initialization. */
1074 	func = smp_load_acquire(&access_kernels[idx]);
1075 	if (func)
1076 		func();
1077 }
1078 
1079 /* The main loop for each thread. */
1080 __no_kcsan
1081 static int access_thread(void *arg)
1082 {
1083 	struct timer_list timer;
1084 	unsigned int cnt = 0;
1085 	unsigned int idx;
1086 	void (*func)(void);
1087 
1088 	timer_setup_on_stack(&timer, access_thread_timer, 0);
1089 	do {
1090 		might_sleep();
1091 
1092 		if (!timer_pending(&timer))
1093 			mod_timer(&timer, jiffies + 1);
1094 		else {
1095 			/* Iterate through all kernels. */
1096 			idx = cnt++ % ARRAY_SIZE(access_kernels);
1097 			/* Acquire potential initialization. */
1098 			func = smp_load_acquire(&access_kernels[idx]);
1099 			if (func)
1100 				func();
1101 		}
1102 	} while (!torture_must_stop());
1103 	del_timer_sync(&timer);
1104 	destroy_timer_on_stack(&timer);
1105 
1106 	torture_kthread_stopping("access_thread");
1107 	return 0;
1108 }
1109 
1110 __no_kcsan
1111 static int test_init(struct kunit *test)
1112 {
1113 	unsigned long flags;
1114 	int nthreads;
1115 	int i;
1116 
1117 	spin_lock_irqsave(&observed.lock, flags);
1118 	for (i = 0; i < ARRAY_SIZE(observed.lines); ++i)
1119 		observed.lines[i][0] = '\0';
1120 	observed.nlines = 0;
1121 	spin_unlock_irqrestore(&observed.lock, flags);
1122 
1123 	if (!torture_init_begin((char *)test->name, 1))
1124 		return -EBUSY;
1125 
1126 	if (WARN_ON(threads))
1127 		goto err;
1128 
1129 	for (i = 0; i < ARRAY_SIZE(access_kernels); ++i) {
1130 		if (WARN_ON(access_kernels[i]))
1131 			goto err;
1132 	}
1133 
1134 	nthreads = abs((long)test->param_value);
1135 	if (WARN_ON(!nthreads))
1136 		goto err;
1137 
1138 	threads = kcalloc(nthreads + 1, sizeof(struct task_struct *), GFP_KERNEL);
1139 	if (WARN_ON(!threads))
1140 		goto err;
1141 
1142 	threads[nthreads] = NULL;
1143 	for (i = 0; i < nthreads; ++i) {
1144 		if (torture_create_kthread(access_thread, NULL, threads[i]))
1145 			goto err;
1146 	}
1147 
1148 	torture_init_end();
1149 
1150 	return 0;
1151 
1152 err:
1153 	kfree(threads);
1154 	threads = NULL;
1155 	torture_init_end();
1156 	return -EINVAL;
1157 }
1158 
1159 __no_kcsan
1160 static void test_exit(struct kunit *test)
1161 {
1162 	struct task_struct **stop_thread;
1163 	int i;
1164 
1165 	if (torture_cleanup_begin())
1166 		return;
1167 
1168 	for (i = 0; i < ARRAY_SIZE(access_kernels); ++i)
1169 		WRITE_ONCE(access_kernels[i], NULL);
1170 
1171 	if (threads) {
1172 		for (stop_thread = threads; *stop_thread; stop_thread++)
1173 			torture_stop_kthread(reader_thread, *stop_thread);
1174 
1175 		kfree(threads);
1176 		threads = NULL;
1177 	}
1178 
1179 	torture_cleanup_end();
1180 }
1181 
1182 static struct kunit_suite kcsan_test_suite = {
1183 	.name = "kcsan",
1184 	.test_cases = kcsan_test_cases,
1185 	.init = test_init,
1186 	.exit = test_exit,
1187 };
1188 static struct kunit_suite *kcsan_test_suites[] = { &kcsan_test_suite, NULL };
1189 
1190 __no_kcsan
1191 static void register_tracepoints(struct tracepoint *tp, void *ignore)
1192 {
1193 	check_trace_callback_type_console(probe_console);
1194 	if (!strcmp(tp->name, "console"))
1195 		WARN_ON(tracepoint_probe_register(tp, probe_console, NULL));
1196 }
1197 
1198 __no_kcsan
1199 static void unregister_tracepoints(struct tracepoint *tp, void *ignore)
1200 {
1201 	if (!strcmp(tp->name, "console"))
1202 		tracepoint_probe_unregister(tp, probe_console, NULL);
1203 }
1204 
1205 /*
1206  * We only want to do tracepoints setup and teardown once, therefore we have to
1207  * customize the init and exit functions and cannot rely on kunit_test_suite().
1208  */
1209 static int __init kcsan_test_init(void)
1210 {
1211 	/*
1212 	 * Because we want to be able to build the test as a module, we need to
1213 	 * iterate through all known tracepoints, since the static registration
1214 	 * won't work here.
1215 	 */
1216 	for_each_kernel_tracepoint(register_tracepoints, NULL);
1217 	return __kunit_test_suites_init(kcsan_test_suites);
1218 }
1219 
1220 static void kcsan_test_exit(void)
1221 {
1222 	__kunit_test_suites_exit(kcsan_test_suites);
1223 	for_each_kernel_tracepoint(unregister_tracepoints, NULL);
1224 	tracepoint_synchronize_unregister();
1225 }
1226 
1227 late_initcall(kcsan_test_init);
1228 module_exit(kcsan_test_exit);
1229 
1230 MODULE_LICENSE("GPL v2");
1231 MODULE_AUTHOR("Marco Elver <elver@google.com>");
1232