kernel/kcsan/kcsan-test.c

   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 #include <kunit/test.h>
  17 #include <linux/jiffies.h>
  18 #include <linux/kcsan-checks.h>
  19 #include <linux/kernel.h>
  20 #include <linux/sched.h>
  21 #include <linux/seqlock.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/string.h>
  24 #include <linux/timer.h>
  25 #include <linux/torture.h>
  26 #include <linux/tracepoint.h>
  27 #include <linux/types.h>
  28 #include <trace/events/printk.h>
  29
  30 #ifdef CONFIG_CC_HAS_TSAN_COMPOUND_READ_BEFORE_WRITE
  31 #define __KCSAN_ACCESS_RW(alt) (KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE)
  32 #else
  33 #define __KCSAN_ACCESS_RW(alt) (alt)
  34 #endif
  35
  36 /* Points to current test-case memory access "kernels". */
  37 static void (*access_kernels[2])(void);
  38
  39 static struct task_struct **threads; /* Lists of threads. */
  40 static unsigned long end_time;       /* End time of test. */
  41
  42 /* Report as observed from console. */
  43 static struct {
  44         spinlock_t lock;
  45         int nlines;
  46         char lines[3][512];
  47 } observed = {
  48         .lock = __SPIN_LOCK_UNLOCKED(observed.lock),
  49 };
  50
  51 /* Setup test checking loop. */
  52 static __no_kcsan inline void
  53 begin_test_checks(void (*func1)(void), void (*func2)(void))
  54 {
  55         kcsan_disable_current();
  56
  57         /*
  58          * Require at least as long as KCSAN_REPORT_ONCE_IN_MS, to ensure at
  59          * least one race is reported.
  60          */
  61         end_time = jiffies + msecs_to_jiffies(CONFIG_KCSAN_REPORT_ONCE_IN_MS + 500);
  62
  63         /* Signal start; release potential initialization of shared data. */
  64         smp_store_release(&access_kernels[0], func1);
  65         smp_store_release(&access_kernels[1], func2);
  66 }
  67
  68 /* End test checking loop. */
  69 static __no_kcsan inline bool
  70 end_test_checks(bool stop)
  71 {
  72         if (!stop && time_before(jiffies, end_time)) {
  73                 /* Continue checking */
  74                 might_sleep();
  75                 return false;
  76         }
  77
  78         kcsan_enable_current();
  79         return true;
  80 }
  81
  82 /*
  83  * Probe for console output: checks if a race was reported, and obtains observed
  84  * lines of interest.
  85  */
  86 __no_kcsan
  87 static void probe_console(void *ignore, const char *buf, size_t len)
  88 {
  89         unsigned long flags;
  90         int nlines;
  91
  92         /*
  93          * Note that KCSAN reports under a global lock, so we do not risk the
  94          * possibility of having multiple reports interleaved. If that were the
  95          * case, we'd expect tests to fail.
  96          */
  97
  98         spin_lock_irqsave(&observed.lock, flags);
  99         nlines = observed.nlines;
 100
 101         if (strnstr(buf, "BUG: KCSAN: ", len) && strnstr(buf, "test_", len)) {
 102                 /*
 103                  * KCSAN report and related to the test.
 104                  *
 105                  * The provided @buf is not NUL-terminated; copy no more than
 106                  * @len bytes and let strscpy() add the missing NUL-terminator.
 107                  */
 108                 strscpy(observed.lines[0], buf, min(len + 1, sizeof(observed.lines[0])));
 109                 nlines = 1;
 110         } else if ((nlines == 1 || nlines == 2) && strnstr(buf, "bytes by", len)) {
 111                 strscpy(observed.lines[nlines++], buf, min(len + 1, sizeof(observed.lines[0])));
 112
 113                 if (strnstr(buf, "race at unknown origin", len)) {
 114                         if (WARN_ON(nlines != 2))
 115                                 goto out;
 116
 117                         /* No second line of interest. */
 118                         strcpy(observed.lines[nlines++], "<none>");
 119                 }
 120         }
 121
 122 out:
 123         WRITE_ONCE(observed.nlines, nlines); /* Publish new nlines. */
 124         spin_unlock_irqrestore(&observed.lock, flags);
 125 }
 126
 127 /* Check if a report related to the test exists. */
 128 __no_kcsan
 129 static bool report_available(void)
 130 {
 131         return READ_ONCE(observed.nlines) == ARRAY_SIZE(observed.lines);
 132 }
 133
 134 /* Report information we expect in a report. */
 135 struct expect_report {
 136         /* Access information of both accesses. */
 137         struct {
 138                 void *fn;    /* Function pointer to expected function of top frame. */
 139                 void *addr;  /* Address of access; unchecked if NULL. */
 140                 size_t size; /* Size of access; unchecked if @addr is NULL. */
 141                 int type;    /* Access type, see KCSAN_ACCESS definitions. */
 142         } access[2];
 143 };
 144
 145 /* Check observed report matches information in @r. */
 146 __no_kcsan
 147 static bool report_matches(const struct expect_report *r)
 148 {
 149         const bool is_assert = (r->access[0].type | r->access[1].type) & KCSAN_ACCESS_ASSERT;
 150         bool ret = false;
 151         unsigned long flags;
 152         typeof(*observed.lines) *expect;
 153         const char *end;
 154         char *cur;
 155         int i;
 156
 157         /* Doubled-checked locking. */
 158         if (!report_available())
 159                 return false;
 160
 161         expect = kmalloc(sizeof(observed.lines), GFP_KERNEL);
 162         if (WARN_ON(!expect))
 163                 return false;
 164
 165         /* Generate expected report contents. */
 166
 167         /* Title */
 168         cur = expect[0];
 169         end = &expect[0][sizeof(expect[0]) - 1];
 170         cur += scnprintf(cur, end - cur, "BUG: KCSAN: %s in ",
 171                          is_assert ? "assert: race" : "data-race");
 172         if (r->access[1].fn) {
 173                 char tmp[2][64];
 174                 int cmp;
 175
 176                 /* Expect lexographically sorted function names in title. */
 177                 scnprintf(tmp[0], sizeof(tmp[0]), "%pS", r->access[0].fn);
 178                 scnprintf(tmp[1], sizeof(tmp[1]), "%pS", r->access[1].fn);
 179                 cmp = strcmp(tmp[0], tmp[1]);
 180                 cur += scnprintf(cur, end - cur, "%ps / %ps",
 181                                  cmp < 0 ? r->access[0].fn : r->access[1].fn,
 182                                  cmp < 0 ? r->access[1].fn : r->access[0].fn);
 183         } else {
 184                 scnprintf(cur, end - cur, "%pS", r->access[0].fn);
 185                 /* The exact offset won't match, remove it. */
 186                 cur = strchr(expect[0], '+');
 187                 if (cur)
 188                         *cur = '\0';
 189         }
 190
 191         /* Access 1 */
 192         cur = expect[1];
 193         end = &expect[1][sizeof(expect[1]) - 1];
 194         if (!r->access[1].fn)
 195                 cur += scnprintf(cur, end - cur, "race at unknown origin, with ");
 196
 197         /* Access 1 & 2 */
 198         for (i = 0; i < 2; ++i) {
 199                 const int ty = r->access[i].type;
 200                 const char *const access_type =
 201                         (ty & KCSAN_ACCESS_ASSERT) ?
 202                                       ((ty & KCSAN_ACCESS_WRITE) ?
 203                                                "assert no accesses" :
 204                                                "assert no writes") :
 205                                       ((ty & KCSAN_ACCESS_WRITE) ?
 206                                                ((ty & KCSAN_ACCESS_COMPOUND) ?
 207                                                         "read-write" :
 208                                                         "write") :
 209                                                "read");
 210                 const char *const access_type_aux =
 211                         (ty & KCSAN_ACCESS_ATOMIC) ?
 212                                       " (marked)" :
 213                                       ((ty & KCSAN_ACCESS_SCOPED) ? " (scoped)" : "");
 214
 215                 if (i == 1) {
 216                         /* Access 2 */
 217                         cur = expect[2];
 218                         end = &expect[2][sizeof(expect[2]) - 1];
 219
 220                         if (!r->access[1].fn) {
 221                                 /* Dummy string if no second access is available. */
 222                                 strcpy(cur, "<none>");
 223                                 break;
 224                         }
 225                 }
 226
 227                 cur += scnprintf(cur, end - cur, "%s%s to ", access_type,
 228                                  access_type_aux);
 229
 230                 if (r->access[i].addr) /* Address is optional. */
 231                         cur += scnprintf(cur, end - cur, "0x%px of %zu bytes",
 232                                          r->access[i].addr, r->access[i].size);
 233         }
 234
 235         spin_lock_irqsave(&observed.lock, flags);
 236         if (!report_available())
 237                 goto out; /* A new report is being captured. */
 238
 239         /* Finally match expected output to what we actually observed. */
 240         ret = strstr(observed.lines[0], expect[0]) &&
 241               /* Access info may appear in any order. */
 242               ((strstr(observed.lines[1], expect[1]) &&
 243                 strstr(observed.lines[2], expect[2])) ||
 244                (strstr(observed.lines[1], expect[2]) &&
 245                 strstr(observed.lines[2], expect[1])));
 246 out:
 247         spin_unlock_irqrestore(&observed.lock, flags);
 248         kfree(expect);
 249         return ret;
 250 }
 251
 252 /* ===== Test kernels ===== */
 253
 254 static long test_sink;
 255 static long test_var;
 256 /* @test_array should be large enough to fall into multiple watchpoint slots. */
 257 static long test_array[3 * PAGE_SIZE / sizeof(long)];
 258 static struct {
 259         long val[8];
 260 } test_struct;
 261 static DEFINE_SEQLOCK(test_seqlock);
 262
 263 /*
 264  * Helper to avoid compiler optimizing out reads, and to generate source values
 265  * for writes.
 266  */
 267 __no_kcsan
 268 static noinline void sink_value(long v) { WRITE_ONCE(test_sink, v); }
 269
 270 static noinline void test_kernel_read(void) { sink_value(test_var); }
 271
 272 static noinline void test_kernel_write(void)
 273 {
 274         test_var = READ_ONCE_NOCHECK(test_sink) + 1;
 275 }
 276
 277 static noinline void test_kernel_write_nochange(void) { test_var = 42; }
 278
 279 /* Suffixed by value-change exception filter. */
 280 static noinline void test_kernel_write_nochange_rcu(void) { test_var = 42; }
 281
 282 static noinline void test_kernel_read_atomic(void)
 283 {
 284         sink_value(READ_ONCE(test_var));
 285 }
 286
 287 static noinline void test_kernel_write_atomic(void)
 288 {
 289         WRITE_ONCE(test_var, READ_ONCE_NOCHECK(test_sink) + 1);
 290 }
 291
 292 static noinline void test_kernel_atomic_rmw(void)
 293 {
 294         /* Use builtin, so we can set up the "bad" atomic/non-atomic scenario. */
 295         __atomic_fetch_add(&test_var, 1, __ATOMIC_RELAXED);
 296 }
 297
 298 __no_kcsan
 299 static noinline void test_kernel_write_uninstrumented(void) { test_var++; }
 300
 301 static noinline void test_kernel_data_race(void) { data_race(test_var++); }
 302
 303 static noinline void test_kernel_assert_writer(void)
 304 {
 305         ASSERT_EXCLUSIVE_WRITER(test_var);
 306 }
 307
 308 static noinline void test_kernel_assert_access(void)
 309 {
 310         ASSERT_EXCLUSIVE_ACCESS(test_var);
 311 }
 312
 313 #define TEST_CHANGE_BITS 0xff00ff00
 314
 315 static noinline void test_kernel_change_bits(void)
 316 {
 317         if (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) {
 318                 /*
 319                  * Avoid race of unknown origin for this test, just pretend they
 320                  * are atomic.
 321                  */
 322                 kcsan_nestable_atomic_begin();
 323                 test_var ^= TEST_CHANGE_BITS;
 324                 kcsan_nestable_atomic_end();
 325         } else
 326                 WRITE_ONCE(test_var, READ_ONCE(test_var) ^ TEST_CHANGE_BITS);
 327 }
 328
 329 static noinline void test_kernel_assert_bits_change(void)
 330 {
 331         ASSERT_EXCLUSIVE_BITS(test_var, TEST_CHANGE_BITS);
 332 }
 333
 334 static noinline void test_kernel_assert_bits_nochange(void)
 335 {
 336         ASSERT_EXCLUSIVE_BITS(test_var, ~TEST_CHANGE_BITS);
 337 }
 338
 339 /* To check that scoped assertions do trigger anywhere in scope. */
 340 static noinline void test_enter_scope(void)
 341 {
 342         int x = 0;
 343
 344         /* Unrelated accesses to scoped assert. */
 345         READ_ONCE(test_sink);
 346         kcsan_check_read(&x, sizeof(x));
 347 }
 348
 349 static noinline void test_kernel_assert_writer_scoped(void)
 350 {
 351         ASSERT_EXCLUSIVE_WRITER_SCOPED(test_var);
 352         test_enter_scope();
 353 }
 354
 355 static noinline void test_kernel_assert_access_scoped(void)
 356 {
 357         ASSERT_EXCLUSIVE_ACCESS_SCOPED(test_var);
 358         test_enter_scope();
 359 }
 360
 361 static noinline void test_kernel_rmw_array(void)
 362 {
 363         int i;
 364
 365         for (i = 0; i < ARRAY_SIZE(test_array); ++i)
 366                 test_array[i]++;
 367 }
 368
 369 static noinline void test_kernel_write_struct(void)
 370 {
 371         kcsan_check_write(&test_struct, sizeof(test_struct));
 372         kcsan_disable_current();
 373         test_struct.val[3]++; /* induce value change */
 374         kcsan_enable_current();
 375 }
 376
 377 static noinline void test_kernel_write_struct_part(void)
 378 {
 379         test_struct.val[3] = 42;
 380 }
 381
 382 static noinline void test_kernel_read_struct_zero_size(void)
 383 {
 384         kcsan_check_read(&test_struct.val[3], 0);
 385 }
 386
 387 static noinline void test_kernel_jiffies_reader(void)
 388 {
 389         sink_value((long)jiffies);
 390 }
 391
 392 static noinline void test_kernel_seqlock_reader(void)
 393 {
 394         unsigned int seq;
 395
 396         do {
 397                 seq = read_seqbegin(&test_seqlock);
 398                 sink_value(test_var);
 399         } while (read_seqretry(&test_seqlock, seq));
 400 }
 401
 402 static noinline void test_kernel_seqlock_writer(void)
 403 {
 404         unsigned long flags;
 405
 406         write_seqlock_irqsave(&test_seqlock, flags);
 407         test_var++;
 408         write_sequnlock_irqrestore(&test_seqlock, flags);
 409 }
 410
 411 static noinline void test_kernel_atomic_builtins(void)
 412 {
 413         /*
 414          * Generate concurrent accesses, expecting no reports, ensuring KCSAN
 415          * treats builtin atomics as actually atomic.
 416          */
 417         __atomic_load_n(&test_var, __ATOMIC_RELAXED);
 418 }
 419
 420 /* ===== Test cases ===== */
 421
 422 /* Simple test with normal data race. */
 423 __no_kcsan
 424 static void test_basic(struct kunit *test)
 425 {
 426         const struct expect_report expect = {
 427                 .access = {
 428                         { test_kernel_write, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
 429                         { test_kernel_read, &test_var, sizeof(test_var), 0 },
 430                 },
 431         };
 432         static const struct expect_report never = {
 433                 .access = {
 434                         { test_kernel_read, &test_var, sizeof(test_var), 0 },
 435                         { test_kernel_read, &test_var, sizeof(test_var), 0 },
 436                 },
 437         };
 438         bool match_expect = false;
 439         bool match_never = false;
 440
 441         begin_test_checks(test_kernel_write, test_kernel_read);
 442         do {
 443                 match_expect |= report_matches(&expect);
 444                 match_never = report_matches(&never);
 445         } while (!end_test_checks(match_never));
 446         KUNIT_EXPECT_TRUE(test, match_expect);
 447         KUNIT_EXPECT_FALSE(test, match_never);
 448 }
 449
 450 /*
 451  * Stress KCSAN with lots of concurrent races on different addresses until
 452  * timeout.
 453  */
 454 __no_kcsan
 455 static void test_concurrent_races(struct kunit *test)
 456 {
 457         const struct expect_report expect = {
 458                 .access = {
 459                         /* NULL will match any address. */
 460                         { test_kernel_rmw_array, NULL, 0, __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) },
 461                         { test_kernel_rmw_array, NULL, 0, __KCSAN_ACCESS_RW(0) },
 462                 },
 463         };
 464         static const struct expect_report never = {
 465                 .access = {
 466                         { test_kernel_rmw_array, NULL, 0, 0 },
 467                         { test_kernel_rmw_array, NULL, 0, 0 },
 468                 },
 469         };
 470         bool match_expect = false;
 471         bool match_never = false;
 472
 473         begin_test_checks(test_kernel_rmw_array, test_kernel_rmw_array);
 474         do {
 475                 match_expect |= report_matches(&expect);
 476                 match_never |= report_matches(&never);
 477         } while (!end_test_checks(false));
 478         KUNIT_EXPECT_TRUE(test, match_expect); /* Sanity check matches exist. */
 479         KUNIT_EXPECT_FALSE(test, match_never);
 480 }
 481
 482 /* Test the KCSAN_REPORT_VALUE_CHANGE_ONLY option. */
 483 __no_kcsan
 484 static void test_novalue_change(struct kunit *test)
 485 {
 486         const struct expect_report expect = {
 487                 .access = {
 488                         { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
 489                         { test_kernel_read, &test_var, sizeof(test_var), 0 },
 490                 },
 491         };
 492         bool match_expect = false;
 493
 494         begin_test_checks(test_kernel_write_nochange, test_kernel_read);
 495         do {
 496                 match_expect = report_matches(&expect);
 497         } while (!end_test_checks(match_expect));
 498         if (IS_ENABLED(CONFIG_KCSAN_REPORT_VALUE_CHANGE_ONLY))
 499                 KUNIT_EXPECT_FALSE(test, match_expect);
 500         else
 501                 KUNIT_EXPECT_TRUE(test, match_expect);
 502 }
 503
 504 /*
 505  * Test that the rules where the KCSAN_REPORT_VALUE_CHANGE_ONLY option should
 506  * never apply work.
 507  */
 508 __no_kcsan
 509 static void test_novalue_change_exception(struct kunit *test)
 510 {
 511         const struct expect_report expect = {
 512                 .access = {
 513                         { test_kernel_write_nochange_rcu, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
 514                         { test_kernel_read, &test_var, sizeof(test_var), 0 },
 515                 },
 516         };
 517         bool match_expect = false;
 518
 519         begin_test_checks(test_kernel_write_nochange_rcu, test_kernel_read);
 520         do {
 521                 match_expect = report_matches(&expect);
 522         } while (!end_test_checks(match_expect));
 523         KUNIT_EXPECT_TRUE(test, match_expect);
 524 }
 525
 526 /* Test that data races of unknown origin are reported. */
 527 __no_kcsan
 528 static void test_unknown_origin(struct kunit *test)
 529 {
 530         const struct expect_report expect = {
 531                 .access = {
 532                         { test_kernel_read, &test_var, sizeof(test_var), 0 },
 533                         { NULL },
 534                 },
 535         };
 536         bool match_expect = false;
 537
 538         begin_test_checks(test_kernel_write_uninstrumented, test_kernel_read);
 539         do {
 540                 match_expect = report_matches(&expect);
 541         } while (!end_test_checks(match_expect));
 542         if (IS_ENABLED(CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN))
 543                 KUNIT_EXPECT_TRUE(test, match_expect);
 544         else
 545                 KUNIT_EXPECT_FALSE(test, match_expect);
 546 }
 547
 548 /* Test KCSAN_ASSUME_PLAIN_WRITES_ATOMIC if it is selected. */
 549 __no_kcsan
 550 static void test_write_write_assume_atomic(struct kunit *test)
 551 {
 552         const struct expect_report expect = {
 553                 .access = {
 554                         { test_kernel_write, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
 555                         { test_kernel_write, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
 556                 },
 557         };
 558         bool match_expect = false;
 559
 560         begin_test_checks(test_kernel_write, test_kernel_write);
 561         do {
 562                 sink_value(READ_ONCE(test_var)); /* induce value-change */
 563                 match_expect = report_matches(&expect);
 564         } while (!end_test_checks(match_expect));
 565         if (IS_ENABLED(CONFIG_KCSAN_ASSUME_PLAIN_WRITES_ATOMIC))
 566                 KUNIT_EXPECT_FALSE(test, match_expect);
 567         else
 568                 KUNIT_EXPECT_TRUE(test, match_expect);
 569 }
 570
 571 /*
 572  * Test that data races with writes larger than word-size are always reported,
 573  * even if KCSAN_ASSUME_PLAIN_WRITES_ATOMIC is selected.
 574  */
 575 __no_kcsan
 576 static void test_write_write_struct(struct kunit *test)
 577 {
 578         const struct expect_report expect = {
 579                 .access = {
 580                         { test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
 581                         { test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
 582                 },
 583         };
 584         bool match_expect = false;
 585
 586         begin_test_checks(test_kernel_write_struct, test_kernel_write_struct);
 587         do {
 588                 match_expect = report_matches(&expect);
 589         } while (!end_test_checks(match_expect));
 590         KUNIT_EXPECT_TRUE(test, match_expect);
 591 }
 592
 593 /*
 594  * Test that data races where only one write is larger than word-size are always
 595  * reported, even if KCSAN_ASSUME_PLAIN_WRITES_ATOMIC is selected.
 596  */
 597 __no_kcsan
 598 static void test_write_write_struct_part(struct kunit *test)
 599 {
 600         const struct expect_report expect = {
 601                 .access = {
 602                         { test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
 603                         { test_kernel_write_struct_part, &test_struct.val[3], sizeof(test_struct.val[3]), KCSAN_ACCESS_WRITE },
 604                 },
 605         };
 606         bool match_expect = false;
 607
 608         begin_test_checks(test_kernel_write_struct, test_kernel_write_struct_part);
 609         do {
 610                 match_expect = report_matches(&expect);
 611         } while (!end_test_checks(match_expect));
 612         KUNIT_EXPECT_TRUE(test, match_expect);
 613 }
 614
 615 /* Test that races with atomic accesses never result in reports. */
 616 __no_kcsan
 617 static void test_read_atomic_write_atomic(struct kunit *test)
 618 {
 619         bool match_never = false;
 620
 621         begin_test_checks(test_kernel_read_atomic, test_kernel_write_atomic);
 622         do {
 623                 match_never = report_available();
 624         } while (!end_test_checks(match_never));
 625         KUNIT_EXPECT_FALSE(test, match_never);
 626 }
 627
 628 /* Test that a race with an atomic and plain access result in reports. */
 629 __no_kcsan
 630 static void test_read_plain_atomic_write(struct kunit *test)
 631 {
 632         const struct expect_report expect = {
 633                 .access = {
 634                         { test_kernel_read, &test_var, sizeof(test_var), 0 },
 635                         { test_kernel_write_atomic, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC },
 636                 },
 637         };
 638         bool match_expect = false;
 639
 640         if (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS))
 641                 return;
 642
 643         begin_test_checks(test_kernel_read, test_kernel_write_atomic);
 644         do {
 645                 match_expect = report_matches(&expect);
 646         } while (!end_test_checks(match_expect));
 647         KUNIT_EXPECT_TRUE(test, match_expect);
 648 }
 649
 650 /* Test that atomic RMWs generate correct report. */
 651 __no_kcsan
 652 static void test_read_plain_atomic_rmw(struct kunit *test)
 653 {
 654         const struct expect_report expect = {
 655                 .access = {
 656                         { test_kernel_read, &test_var, sizeof(test_var), 0 },
 657                         { test_kernel_atomic_rmw, &test_var, sizeof(test_var),
 658                                 KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC },
 659                 },
 660         };
 661         bool match_expect = false;
 662
 663         if (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS))
 664                 return;
 665
 666         begin_test_checks(test_kernel_read, test_kernel_atomic_rmw);
 667         do {
 668                 match_expect = report_matches(&expect);
 669         } while (!end_test_checks(match_expect));
 670         KUNIT_EXPECT_TRUE(test, match_expect);
 671 }
 672
 673 /* Zero-sized accesses should never cause data race reports. */
 674 __no_kcsan
 675 static void test_zero_size_access(struct kunit *test)
 676 {
 677         const struct expect_report expect = {
 678                 .access = {
 679                         { test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
 680                         { test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
 681                 },
 682         };
 683         const struct expect_report never = {
 684                 .access = {
 685                         { test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
 686                         { test_kernel_read_struct_zero_size, &test_struct.val[3], 0, 0 },
 687                 },
 688         };
 689         bool match_expect = false;
 690         bool match_never = false;
 691
 692         begin_test_checks(test_kernel_write_struct, test_kernel_read_struct_zero_size);
 693         do {
 694                 match_expect |= report_matches(&expect);
 695                 match_never = report_matches(&never);
 696         } while (!end_test_checks(match_never));
 697         KUNIT_EXPECT_TRUE(test, match_expect); /* Sanity check. */
 698         KUNIT_EXPECT_FALSE(test, match_never);
 699 }
 700
 701 /* Test the data_race() macro. */
 702 __no_kcsan
 703 static void test_data_race(struct kunit *test)
 704 {
 705         bool match_never = false;
 706
 707         begin_test_checks(test_kernel_data_race, test_kernel_data_race);
 708         do {
 709                 match_never = report_available();
 710         } while (!end_test_checks(match_never));
 711         KUNIT_EXPECT_FALSE(test, match_never);
 712 }
 713
 714 __no_kcsan
 715 static void test_assert_exclusive_writer(struct kunit *test)
 716 {
 717         const struct expect_report expect = {
 718                 .access = {
 719                         { test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
 720                         { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
 721                 },
 722         };
 723         bool match_expect = false;
 724
 725         begin_test_checks(test_kernel_assert_writer, test_kernel_write_nochange);
 726         do {
 727                 match_expect = report_matches(&expect);
 728         } while (!end_test_checks(match_expect));
 729         KUNIT_EXPECT_TRUE(test, match_expect);
 730 }
 731
 732 __no_kcsan
 733 static void test_assert_exclusive_access(struct kunit *test)
 734 {
 735         const struct expect_report expect = {
 736                 .access = {
 737                         { test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE },
 738                         { test_kernel_read, &test_var, sizeof(test_var), 0 },
 739                 },
 740         };
 741         bool match_expect = false;
 742
 743         begin_test_checks(test_kernel_assert_access, test_kernel_read);
 744         do {
 745                 match_expect = report_matches(&expect);
 746         } while (!end_test_checks(match_expect));
 747         KUNIT_EXPECT_TRUE(test, match_expect);
 748 }
 749
 750 __no_kcsan
 751 static void test_assert_exclusive_access_writer(struct kunit *test)
 752 {
 753         const struct expect_report expect_access_writer = {
 754                 .access = {
 755                         { test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE },
 756                         { test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
 757                 },
 758         };
 759         const struct expect_report expect_access_access = {
 760                 .access = {
 761                         { test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE },
 762                         { test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE },
 763                 },
 764         };
 765         const struct expect_report never = {
 766                 .access = {
 767                         { test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
 768                         { test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
 769                 },
 770         };
 771         bool match_expect_access_writer = false;
 772         bool match_expect_access_access = false;
 773         bool match_never = false;
 774
 775         begin_test_checks(test_kernel_assert_access, test_kernel_assert_writer);
 776         do {
 777                 match_expect_access_writer |= report_matches(&expect_access_writer);
 778                 match_expect_access_access |= report_matches(&expect_access_access);
 779                 match_never |= report_matches(&never);
 780         } while (!end_test_checks(match_never));
 781         KUNIT_EXPECT_TRUE(test, match_expect_access_writer);
 782         KUNIT_EXPECT_TRUE(test, match_expect_access_access);
 783         KUNIT_EXPECT_FALSE(test, match_never);
 784 }
 785
 786 __no_kcsan
 787 static void test_assert_exclusive_bits_change(struct kunit *test)
 788 {
 789         const struct expect_report expect = {
 790                 .access = {
 791                         { test_kernel_assert_bits_change, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
 792                         { test_kernel_change_bits, &test_var, sizeof(test_var),
 793                                 KCSAN_ACCESS_WRITE | (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS) ? 0 : KCSAN_ACCESS_ATOMIC) },
 794                 },
 795         };
 796         bool match_expect = false;
 797
 798         begin_test_checks(test_kernel_assert_bits_change, test_kernel_change_bits);
 799         do {
 800                 match_expect = report_matches(&expect);
 801         } while (!end_test_checks(match_expect));
 802         KUNIT_EXPECT_TRUE(test, match_expect);
 803 }
 804
 805 __no_kcsan
 806 static void test_assert_exclusive_bits_nochange(struct kunit *test)
 807 {
 808         bool match_never = false;
 809
 810         begin_test_checks(test_kernel_assert_bits_nochange, test_kernel_change_bits);
 811         do {
 812                 match_never = report_available();
 813         } while (!end_test_checks(match_never));
 814         KUNIT_EXPECT_FALSE(test, match_never);
 815 }
 816
 817 __no_kcsan
 818 static void test_assert_exclusive_writer_scoped(struct kunit *test)
 819 {
 820         const struct expect_report expect_start = {
 821                 .access = {
 822                         { test_kernel_assert_writer_scoped, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_SCOPED },
 823                         { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
 824                 },
 825         };
 826         const struct expect_report expect_anywhere = {
 827                 .access = {
 828                         { test_enter_scope, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_SCOPED },
 829                         { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
 830                 },
 831         };
 832         bool match_expect_start = false;
 833         bool match_expect_anywhere = false;
 834
 835         begin_test_checks(test_kernel_assert_writer_scoped, test_kernel_write_nochange);
 836         do {
 837                 match_expect_start |= report_matches(&expect_start);
 838                 match_expect_anywhere |= report_matches(&expect_anywhere);
 839         } while (!end_test_checks(match_expect_start && match_expect_anywhere));
 840         KUNIT_EXPECT_TRUE(test, match_expect_start);
 841         KUNIT_EXPECT_TRUE(test, match_expect_anywhere);
 842 }
 843
 844 __no_kcsan
 845 static void test_assert_exclusive_access_scoped(struct kunit *test)
 846 {
 847         const struct expect_report expect_start1 = {
 848                 .access = {
 849                         { test_kernel_assert_access_scoped, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_SCOPED },
 850                         { test_kernel_read, &test_var, sizeof(test_var), 0 },
 851                 },
 852         };
 853         const struct expect_report expect_start2 = {
 854                 .access = { expect_start1.access[0], expect_start1.access[0] },
 855         };
 856         const struct expect_report expect_inscope = {
 857                 .access = {
 858                         { test_enter_scope, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_SCOPED },
 859                         { test_kernel_read, &test_var, sizeof(test_var), 0 },
 860                 },
 861         };
 862         bool match_expect_start = false;
 863         bool match_expect_inscope = false;
 864
 865         begin_test_checks(test_kernel_assert_access_scoped, test_kernel_read);
 866         end_time += msecs_to_jiffies(1000); /* This test requires a bit more time. */
 867         do {
 868                 match_expect_start |= report_matches(&expect_start1) || report_matches(&expect_start2);
 869                 match_expect_inscope |= report_matches(&expect_inscope);
 870         } while (!end_test_checks(match_expect_start && match_expect_inscope));
 871         KUNIT_EXPECT_TRUE(test, match_expect_start);
 872         KUNIT_EXPECT_TRUE(test, match_expect_inscope);
 873 }
 874
 875 /*
 876  * jiffies is special (declared to be volatile) and its accesses are typically
 877  * not marked; this test ensures that the compiler nor KCSAN gets confused about
 878  * jiffies's declaration on different architectures.
 879  */
 880 __no_kcsan
 881 static void test_jiffies_noreport(struct kunit *test)
 882 {
 883         bool match_never = false;
 884
 885         begin_test_checks(test_kernel_jiffies_reader, test_kernel_jiffies_reader);
 886         do {
 887                 match_never = report_available();
 888         } while (!end_test_checks(match_never));
 889         KUNIT_EXPECT_FALSE(test, match_never);
 890 }
 891
 892 /* Test that racing accesses in seqlock critical sections are not reported. */
 893 __no_kcsan
 894 static void test_seqlock_noreport(struct kunit *test)
 895 {
 896         bool match_never = false;
 897
 898         begin_test_checks(test_kernel_seqlock_reader, test_kernel_seqlock_writer);
 899         do {
 900                 match_never = report_available();
 901         } while (!end_test_checks(match_never));
 902         KUNIT_EXPECT_FALSE(test, match_never);
 903 }
 904
 905 /*
 906  * Test atomic builtins work and required instrumentation functions exist. We
 907  * also test that KCSAN understands they're atomic by racing with them via
 908  * test_kernel_atomic_builtins(), and expect no reports.
 909  *
 910  * The atomic builtins _SHOULD NOT_ be used in normal kernel code!
 911  */
 912 static void test_atomic_builtins(struct kunit *test)
 913 {
 914         bool match_never = false;
 915
 916         begin_test_checks(test_kernel_atomic_builtins, test_kernel_atomic_builtins);
 917         do {
 918                 long tmp;
 919
 920                 kcsan_enable_current();
 921
 922                 __atomic_store_n(&test_var, 42L, __ATOMIC_RELAXED);
 923                 KUNIT_EXPECT_EQ(test, 42L, __atomic_load_n(&test_var, __ATOMIC_RELAXED));
 924
 925                 KUNIT_EXPECT_EQ(test, 42L, __atomic_exchange_n(&test_var, 20, __ATOMIC_RELAXED));
 926                 KUNIT_EXPECT_EQ(test, 20L, test_var);
 927
 928                 tmp = 20L;
 929                 KUNIT_EXPECT_TRUE(test, __atomic_compare_exchange_n(&test_var, &tmp, 30L,
 930                                                                     0, __ATOMIC_RELAXED,
 931                                                                     __ATOMIC_RELAXED));
 932                 KUNIT_EXPECT_EQ(test, tmp, 20L);
 933                 KUNIT_EXPECT_EQ(test, test_var, 30L);
 934                 KUNIT_EXPECT_FALSE(test, __atomic_compare_exchange_n(&test_var, &tmp, 40L,
 935                                                                      1, __ATOMIC_RELAXED,
 936                                                                      __ATOMIC_RELAXED));
 937                 KUNIT_EXPECT_EQ(test, tmp, 30L);
 938                 KUNIT_EXPECT_EQ(test, test_var, 30L);
 939
 940                 KUNIT_EXPECT_EQ(test, 30L, __atomic_fetch_add(&test_var, 1, __ATOMIC_RELAXED));
 941                 KUNIT_EXPECT_EQ(test, 31L, __atomic_fetch_sub(&test_var, 1, __ATOMIC_RELAXED));
 942                 KUNIT_EXPECT_EQ(test, 30L, __atomic_fetch_and(&test_var, 0xf, __ATOMIC_RELAXED));
 943                 KUNIT_EXPECT_EQ(test, 14L, __atomic_fetch_xor(&test_var, 0xf, __ATOMIC_RELAXED));
 944                 KUNIT_EXPECT_EQ(test, 1L, __atomic_fetch_or(&test_var, 0xf0, __ATOMIC_RELAXED));
 945                 KUNIT_EXPECT_EQ(test, 241L, __atomic_fetch_nand(&test_var, 0xf, __ATOMIC_RELAXED));
 946                 KUNIT_EXPECT_EQ(test, -2L, test_var);
 947
 948                 __atomic_thread_fence(__ATOMIC_SEQ_CST);
 949                 __atomic_signal_fence(__ATOMIC_SEQ_CST);
 950
 951                 kcsan_disable_current();
 952
 953                 match_never = report_available();
 954         } while (!end_test_checks(match_never));
 955         KUNIT_EXPECT_FALSE(test, match_never);
 956 }
 957
 958 /*
 959  * Each test case is run with different numbers of threads. Until KUnit supports
 960  * passing arguments for each test case, we encode #threads in the test case
 961  * name (read by get_num_threads()). [The '-' was chosen as a stylistic
 962  * preference to separate test name and #threads.]
 963  *
 964  * The thread counts are chosen to cover potentially interesting boundaries and
 965  * corner cases (range 2-5), and then stress the system with larger counts.
 966  */
 967 #define KCSAN_KUNIT_CASE(test_name)                                            \
 968         { .run_case = test_name, .name = #test_name "-02" },                   \
 969         { .run_case = test_name, .name = #test_name "-03" },                   \
 970         { .run_case = test_name, .name = #test_name "-04" },                   \
 971         { .run_case = test_name, .name = #test_name "-05" },                   \
 972         { .run_case = test_name, .name = #test_name "-08" },                   \
 973         { .run_case = test_name, .name = #test_name "-16" }
 974
 975 static struct kunit_case kcsan_test_cases[] = {
 976         KCSAN_KUNIT_CASE(test_basic),
 977         KCSAN_KUNIT_CASE(test_concurrent_races),
 978         KCSAN_KUNIT_CASE(test_novalue_change),
 979         KCSAN_KUNIT_CASE(test_novalue_change_exception),
 980         KCSAN_KUNIT_CASE(test_unknown_origin),
 981         KCSAN_KUNIT_CASE(test_write_write_assume_atomic),
 982         KCSAN_KUNIT_CASE(test_write_write_struct),
 983         KCSAN_KUNIT_CASE(test_write_write_struct_part),
 984         KCSAN_KUNIT_CASE(test_read_atomic_write_atomic),
 985         KCSAN_KUNIT_CASE(test_read_plain_atomic_write),
 986         KCSAN_KUNIT_CASE(test_read_plain_atomic_rmw),
 987         KCSAN_KUNIT_CASE(test_zero_size_access),
 988         KCSAN_KUNIT_CASE(test_data_race),
 989         KCSAN_KUNIT_CASE(test_assert_exclusive_writer),
 990         KCSAN_KUNIT_CASE(test_assert_exclusive_access),
 991         KCSAN_KUNIT_CASE(test_assert_exclusive_access_writer),
 992         KCSAN_KUNIT_CASE(test_assert_exclusive_bits_change),
 993         KCSAN_KUNIT_CASE(test_assert_exclusive_bits_nochange),
 994         KCSAN_KUNIT_CASE(test_assert_exclusive_writer_scoped),
 995         KCSAN_KUNIT_CASE(test_assert_exclusive_access_scoped),
 996         KCSAN_KUNIT_CASE(test_jiffies_noreport),
 997         KCSAN_KUNIT_CASE(test_seqlock_noreport),
 998         KCSAN_KUNIT_CASE(test_atomic_builtins),
 999         {},
1000 };
1001
1002 /* ===== End test cases ===== */
1003
1004 /* Get number of threads encoded in test name. */
1005 static bool __no_kcsan
1006 get_num_threads(const char *test, int *nthreads)
1007 {
1008         int len = strlen(test);
1009
1010         if (WARN_ON(len < 3))
1011                 return false;
1012
1013         *nthreads = test[len - 1] - '0';
1014         *nthreads += (test[len - 2] - '0') * 10;
1015
1016         if (WARN_ON(*nthreads < 0))
1017                 return false;
1018
1019         return true;
1020 }
1021
1022 /* Concurrent accesses from interrupts. */
1023 __no_kcsan
1024 static void access_thread_timer(struct timer_list *timer)
1025 {
1026         static atomic_t cnt = ATOMIC_INIT(0);
1027         unsigned int idx;
1028         void (*func)(void);
1029
1030         idx = (unsigned int)atomic_inc_return(&cnt) % ARRAY_SIZE(access_kernels);
1031         /* Acquire potential initialization. */
1032         func = smp_load_acquire(&access_kernels[idx]);
1033         if (func)
1034                 func();
1035 }
1036
1037 /* The main loop for each thread. */
1038 __no_kcsan
1039 static int access_thread(void *arg)
1040 {
1041         struct timer_list timer;
1042         unsigned int cnt = 0;
1043         unsigned int idx;
1044         void (*func)(void);
1045
1046         timer_setup_on_stack(&timer, access_thread_timer, 0);
1047         do {
1048                 might_sleep();
1049
1050                 if (!timer_pending(&timer))
1051                         mod_timer(&timer, jiffies + 1);
1052                 else {
1053                         /* Iterate through all kernels. */
1054                         idx = cnt++ % ARRAY_SIZE(access_kernels);
1055                         /* Acquire potential initialization. */
1056                         func = smp_load_acquire(&access_kernels[idx]);
1057                         if (func)
1058                                 func();
1059                 }
1060         } while (!torture_must_stop());
1061         del_timer_sync(&timer);
1062         destroy_timer_on_stack(&timer);
1063
1064         torture_kthread_stopping("access_thread");
1065         return 0;
1066 }
1067
1068 __no_kcsan
1069 static int test_init(struct kunit *test)
1070 {
1071         unsigned long flags;
1072         int nthreads;
1073         int i;
1074
1075         spin_lock_irqsave(&observed.lock, flags);
1076         for (i = 0; i < ARRAY_SIZE(observed.lines); ++i)
1077                 observed.lines[i][0] = '\0';
1078         observed.nlines = 0;
1079         spin_unlock_irqrestore(&observed.lock, flags);
1080
1081         if (!torture_init_begin((char *)test->name, 1))
1082                 return -EBUSY;
1083
1084         if (!get_num_threads(test->name, &nthreads))
1085                 goto err;
1086
1087         if (WARN_ON(threads))
1088                 goto err;
1089
1090         for (i = 0; i < ARRAY_SIZE(access_kernels); ++i) {
1091                 if (WARN_ON(access_kernels[i]))
1092                         goto err;
1093         }
1094
1095         if (!IS_ENABLED(CONFIG_PREEMPT) || !IS_ENABLED(CONFIG_KCSAN_INTERRUPT_WATCHER)) {
1096                 /*
1097                  * Without any preemption, keep 2 CPUs free for other tasks, one
1098                  * of which is the main test case function checking for
1099                  * completion or failure.
1100                  */
1101                 const int min_unused_cpus = IS_ENABLED(CONFIG_PREEMPT_NONE) ? 2 : 0;
1102                 const int min_required_cpus = 2 + min_unused_cpus;
1103
1104                 if (num_online_cpus() < min_required_cpus) {
1105                         pr_err("%s: too few online CPUs (%u < %d) for test",
1106                                test->name, num_online_cpus(), min_required_cpus);
1107                         goto err;
1108                 } else if (nthreads > num_online_cpus() - min_unused_cpus) {
1109                         nthreads = num_online_cpus() - min_unused_cpus;
1110                         pr_warn("%s: limiting number of threads to %d\n",
1111                                 test->name, nthreads);
1112                 }
1113         }
1114
1115         if (nthreads) {
1116                 threads = kcalloc(nthreads + 1, sizeof(struct task_struct *),
1117                                   GFP_KERNEL);
1118                 if (WARN_ON(!threads))
1119                         goto err;
1120
1121                 threads[nthreads] = NULL;
1122                 for (i = 0; i < nthreads; ++i) {
1123                         if (torture_create_kthread(access_thread, NULL,
1124                                                    threads[i]))
1125                                 goto err;
1126                 }
1127         }
1128
1129         torture_init_end();
1130
1131         return 0;
1132
1133 err:
1134         kfree(threads);
1135         threads = NULL;
1136         torture_init_end();
1137         return -EINVAL;
1138 }
1139
1140 __no_kcsan
1141 static void test_exit(struct kunit *test)
1142 {
1143         struct task_struct **stop_thread;
1144         int i;
1145
1146         if (torture_cleanup_begin())
1147                 return;
1148
1149         for (i = 0; i < ARRAY_SIZE(access_kernels); ++i)
1150                 WRITE_ONCE(access_kernels[i], NULL);
1151
1152         if (threads) {
1153                 for (stop_thread = threads; *stop_thread; stop_thread++)
1154                         torture_stop_kthread(reader_thread, *stop_thread);
1155
1156                 kfree(threads);
1157                 threads = NULL;
1158         }
1159
1160         torture_cleanup_end();
1161 }
1162
1163 static struct kunit_suite kcsan_test_suite = {
1164         .name = "kcsan-test",
1165         .test_cases = kcsan_test_cases,
1166         .init = test_init,
1167         .exit = test_exit,
1168 };
1169 static struct kunit_suite *kcsan_test_suites[] = { &kcsan_test_suite, NULL };
1170
1171 __no_kcsan
1172 static void register_tracepoints(struct tracepoint *tp, void *ignore)
1173 {
1174         check_trace_callback_type_console(probe_console);
1175         if (!strcmp(tp->name, "console"))
1176                 WARN_ON(tracepoint_probe_register(tp, probe_console, NULL));
1177 }
1178
1179 __no_kcsan
1180 static void unregister_tracepoints(struct tracepoint *tp, void *ignore)
1181 {
1182         if (!strcmp(tp->name, "console"))
1183                 tracepoint_probe_unregister(tp, probe_console, NULL);
1184 }
1185
1186 /*
1187  * We only want to do tracepoints setup and teardown once, therefore we have to
1188  * customize the init and exit functions and cannot rely on kunit_test_suite().
1189  */
1190 static int __init kcsan_test_init(void)
1191 {
1192         /*
1193          * Because we want to be able to build the test as a module, we need to
1194          * iterate through all known tracepoints, since the static registration
1195          * won't work here.
1196          */
1197         for_each_kernel_tracepoint(register_tracepoints, NULL);
1198         return __kunit_test_suites_init(kcsan_test_suites);
1199 }
1200
1201 static void kcsan_test_exit(void)
1202 {
1203         __kunit_test_suites_exit(kcsan_test_suites);
1204         for_each_kernel_tracepoint(unregister_tracepoints, NULL);
1205         tracepoint_synchronize_unregister();
1206 }
1207
1208 late_initcall(kcsan_test_init);
1209 module_exit(kcsan_test_exit);
1210
1211 MODULE_LICENSE("GPL v2");
1212 MODULE_AUTHOR("Marco Elver <elver@google.com>");