libsanitizer/tsan/tsan_rtl.cpp

   1 //===-- tsan_rtl.cpp ------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is a part of ThreadSanitizer (TSan), a race detector.
  10 //
  11 // Main file (entry points) for the TSan run-time.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "tsan_rtl.h"
  15
  16 #include "sanitizer_common/sanitizer_atomic.h"
  17 #include "sanitizer_common/sanitizer_common.h"
  18 #include "sanitizer_common/sanitizer_file.h"
  19 #include "sanitizer_common/sanitizer_libc.h"
  20 #include "sanitizer_common/sanitizer_placement_new.h"
  21 #include "sanitizer_common/sanitizer_stackdepot.h"
  22 #include "sanitizer_common/sanitizer_symbolizer.h"
  23 #include "tsan_defs.h"
  24 #include "tsan_interface.h"
  25 #include "tsan_mman.h"
  26 #include "tsan_platform.h"
  27 #include "tsan_suppressions.h"
  28 #include "tsan_symbolize.h"
  29 #include "ubsan/ubsan_init.h"
  30
  31 volatile int __tsan_resumed = 0;
  32
  33 extern "C" void __tsan_resume() {
  34   __tsan_resumed = 1;
  35 }
  36
  37 namespace __tsan {
  38
  39 #if !SANITIZER_GO
  40 void (*on_initialize)(void);
  41 int (*on_finalize)(int);
  42 #endif
  43
  44 #if !SANITIZER_GO && !SANITIZER_MAC
  45 __attribute__((tls_model("initial-exec")))
  46 THREADLOCAL char cur_thread_placeholder[sizeof(ThreadState)] ALIGNED(
  47     SANITIZER_CACHE_LINE_SIZE);
  48 #endif
  49 static char ctx_placeholder[sizeof(Context)] ALIGNED(SANITIZER_CACHE_LINE_SIZE);
  50 Context *ctx;
  51
  52 // Can be overriden by a front-end.
  53 #ifdef TSAN_EXTERNAL_HOOKS
  54 bool OnFinalize(bool failed);
  55 void OnInitialize();
  56 #else
  57 #include <dlfcn.h>
  58 SANITIZER_WEAK_CXX_DEFAULT_IMPL
  59 bool OnFinalize(bool failed) {
  60 #if !SANITIZER_GO
  61   if (on_finalize)
  62     return on_finalize(failed);
  63 #endif
  64   return failed;
  65 }
  66 SANITIZER_WEAK_CXX_DEFAULT_IMPL
  67 void OnInitialize() {
  68 #if !SANITIZER_GO
  69   if (on_initialize)
  70     on_initialize();
  71 #endif
  72 }
  73 #endif
  74
  75 static ThreadContextBase *CreateThreadContext(Tid tid) {
  76   // Map thread trace when context is created.
  77   char name[50];
  78   internal_snprintf(name, sizeof(name), "trace %u", tid);
  79   MapThreadTrace(GetThreadTrace(tid), TraceSize() * sizeof(Event), name);
  80   const uptr hdr = GetThreadTraceHeader(tid);
  81   internal_snprintf(name, sizeof(name), "trace header %u", tid);
  82   MapThreadTrace(hdr, sizeof(Trace), name);
  83   new((void*)hdr) Trace();
  84   // We are going to use only a small part of the trace with the default
  85   // value of history_size. However, the constructor writes to the whole trace.
  86   // Release the unused part.
  87   uptr hdr_end = hdr + sizeof(Trace);
  88   hdr_end -= sizeof(TraceHeader) * (kTraceParts - TraceParts());
  89   hdr_end = RoundUp(hdr_end, GetPageSizeCached());
  90   if (hdr_end < hdr + sizeof(Trace)) {
  91     ReleaseMemoryPagesToOS(hdr_end, hdr + sizeof(Trace));
  92     uptr unused = hdr + sizeof(Trace) - hdr_end;
  93     if (hdr_end != (uptr)MmapFixedNoAccess(hdr_end, unused)) {
  94       Report("ThreadSanitizer: failed to mprotect [0x%zx-0x%zx) \n", hdr_end,
  95              unused);
  96       CHECK("unable to mprotect" && 0);
  97     }
  98   }
  99   return New<ThreadContext>(tid);
 100 }
 101
 102 #if !SANITIZER_GO
 103 static const u32 kThreadQuarantineSize = 16;
 104 #else
 105 static const u32 kThreadQuarantineSize = 64;
 106 #endif
 107
 108 Context::Context()
 109     : initialized(),
 110       report_mtx(MutexTypeReport),
 111       nreported(),
 112       thread_registry(CreateThreadContext, kMaxTid, kThreadQuarantineSize,
 113                       kMaxTidReuse),
 114       racy_mtx(MutexTypeRacy),
 115       racy_stacks(),
 116       racy_addresses(),
 117       fired_suppressions_mtx(MutexTypeFired),
 118       clock_alloc(LINKER_INITIALIZED, "clock allocator") {
 119   fired_suppressions.reserve(8);
 120 }
 121
 122 // The objects are allocated in TLS, so one may rely on zero-initialization.
 123 ThreadState::ThreadState(Context *ctx, Tid tid, int unique_id, u64 epoch,
 124                          unsigned reuse_count, uptr stk_addr, uptr stk_size,
 125                          uptr tls_addr, uptr tls_size)
 126     : fast_state(tid, epoch)
 127       // Do not touch these, rely on zero initialization,
 128       // they may be accessed before the ctor.
 129       // , ignore_reads_and_writes()
 130       // , ignore_interceptors()
 131       ,
 132       clock(tid, reuse_count)
 133 #if !SANITIZER_GO
 134       ,
 135       jmp_bufs()
 136 #endif
 137       ,
 138       tid(tid),
 139       unique_id(unique_id),
 140       stk_addr(stk_addr),
 141       stk_size(stk_size),
 142       tls_addr(tls_addr),
 143       tls_size(tls_size)
 144 #if !SANITIZER_GO
 145       ,
 146       last_sleep_clock(tid)
 147 #endif
 148 {
 149   CHECK_EQ(reinterpret_cast<uptr>(this) % SANITIZER_CACHE_LINE_SIZE, 0);
 150 #if !SANITIZER_GO
 151   shadow_stack_pos = shadow_stack;
 152   shadow_stack_end = shadow_stack + kShadowStackSize;
 153 #else
 154   // Setup dynamic shadow stack.
 155   const int kInitStackSize = 8;
 156   shadow_stack = (uptr *)Alloc(kInitStackSize * sizeof(uptr));
 157   shadow_stack_pos = shadow_stack;
 158   shadow_stack_end = shadow_stack + kInitStackSize;
 159 #endif
 160 }
 161
 162 #if !SANITIZER_GO
 163 void MemoryProfiler(u64 uptime) {
 164   if (ctx->memprof_fd == kInvalidFd)
 165     return;
 166   InternalMmapVector<char> buf(4096);
 167   WriteMemoryProfile(buf.data(), buf.size(), uptime);
 168   WriteToFile(ctx->memprof_fd, buf.data(), internal_strlen(buf.data()));
 169 }
 170
 171 void InitializeMemoryProfiler() {
 172   ctx->memprof_fd = kInvalidFd;
 173   const char *fname = flags()->profile_memory;
 174   if (!fname || !fname[0])
 175     return;
 176   if (internal_strcmp(fname, "stdout") == 0) {
 177     ctx->memprof_fd = 1;
 178   } else if (internal_strcmp(fname, "stderr") == 0) {
 179     ctx->memprof_fd = 2;
 180   } else {
 181     InternalScopedString filename;
 182     filename.append("%s.%d", fname, (int)internal_getpid());
 183     ctx->memprof_fd = OpenFile(filename.data(), WrOnly);
 184     if (ctx->memprof_fd == kInvalidFd) {
 185       Printf("ThreadSanitizer: failed to open memory profile file '%s'\n",
 186              filename.data());
 187       return;
 188     }
 189   }
 190   MemoryProfiler(0);
 191   MaybeSpawnBackgroundThread();
 192 }
 193
 194 static void *BackgroundThread(void *arg) {
 195   // This is a non-initialized non-user thread, nothing to see here.
 196   // We don't use ScopedIgnoreInterceptors, because we want ignores to be
 197   // enabled even when the thread function exits (e.g. during pthread thread
 198   // shutdown code).
 199   cur_thread_init()->ignore_interceptors++;
 200   const u64 kMs2Ns = 1000 * 1000;
 201   const u64 start = NanoTime();
 202
 203   u64 last_flush = NanoTime();
 204   uptr last_rss = 0;
 205   for (int i = 0;
 206       atomic_load(&ctx->stop_background_thread, memory_order_relaxed) == 0;
 207       i++) {
 208     SleepForMillis(100);
 209     u64 now = NanoTime();
 210
 211     // Flush memory if requested.
 212     if (flags()->flush_memory_ms > 0) {
 213       if (last_flush + flags()->flush_memory_ms * kMs2Ns < now) {
 214         VPrintf(1, "ThreadSanitizer: periodic memory flush\n");
 215         FlushShadowMemory();
 216         last_flush = NanoTime();
 217       }
 218     }
 219     if (flags()->memory_limit_mb > 0) {
 220       uptr rss = GetRSS();
 221       uptr limit = uptr(flags()->memory_limit_mb) << 20;
 222       VPrintf(1, "ThreadSanitizer: memory flush check"
 223                  " RSS=%llu LAST=%llu LIMIT=%llu\n",
 224               (u64)rss >> 20, (u64)last_rss >> 20, (u64)limit >> 20);
 225       if (2 * rss > limit + last_rss) {
 226         VPrintf(1, "ThreadSanitizer: flushing memory due to RSS\n");
 227         FlushShadowMemory();
 228         rss = GetRSS();
 229         VPrintf(1, "ThreadSanitizer: memory flushed RSS=%llu\n", (u64)rss>>20);
 230       }
 231       last_rss = rss;
 232     }
 233
 234     MemoryProfiler(now - start);
 235
 236     // Flush symbolizer cache if requested.
 237     if (flags()->flush_symbolizer_ms > 0) {
 238       u64 last = atomic_load(&ctx->last_symbolize_time_ns,
 239                              memory_order_relaxed);
 240       if (last != 0 && last + flags()->flush_symbolizer_ms * kMs2Ns < now) {
 241         Lock l(&ctx->report_mtx);
 242         ScopedErrorReportLock l2;
 243         SymbolizeFlush();
 244         atomic_store(&ctx->last_symbolize_time_ns, 0, memory_order_relaxed);
 245       }
 246     }
 247   }
 248   return nullptr;
 249 }
 250
 251 static void StartBackgroundThread() {
 252   ctx->background_thread = internal_start_thread(&BackgroundThread, 0);
 253 }
 254
 255 #ifndef __mips__
 256 static void StopBackgroundThread() {
 257   atomic_store(&ctx->stop_background_thread, 1, memory_order_relaxed);
 258   internal_join_thread(ctx->background_thread);
 259   ctx->background_thread = 0;
 260 }
 261 #endif
 262 #endif
 263
 264 void DontNeedShadowFor(uptr addr, uptr size) {
 265   ReleaseMemoryPagesToOS(reinterpret_cast<uptr>(MemToShadow(addr)),
 266                          reinterpret_cast<uptr>(MemToShadow(addr + size)));
 267 }
 268
 269 #if !SANITIZER_GO
 270 void UnmapShadow(ThreadState *thr, uptr addr, uptr size) {
 271   if (size == 0) return;
 272   DontNeedShadowFor(addr, size);
 273   ScopedGlobalProcessor sgp;
 274   ctx->metamap.ResetRange(thr->proc(), addr, size);
 275 }
 276 #endif
 277
 278 void MapShadow(uptr addr, uptr size) {
 279   // Global data is not 64K aligned, but there are no adjacent mappings,
 280   // so we can get away with unaligned mapping.
 281   // CHECK_EQ(addr, addr & ~((64 << 10) - 1));  // windows wants 64K alignment
 282   const uptr kPageSize = GetPageSizeCached();
 283   uptr shadow_begin = RoundDownTo((uptr)MemToShadow(addr), kPageSize);
 284   uptr shadow_end = RoundUpTo((uptr)MemToShadow(addr + size), kPageSize);
 285   if (!MmapFixedSuperNoReserve(shadow_begin, shadow_end - shadow_begin,
 286                                "shadow"))
 287     Die();
 288
 289   // Meta shadow is 2:1, so tread carefully.
 290   static bool data_mapped = false;
 291   static uptr mapped_meta_end = 0;
 292   uptr meta_begin = (uptr)MemToMeta(addr);
 293   uptr meta_end = (uptr)MemToMeta(addr + size);
 294   meta_begin = RoundDownTo(meta_begin, 64 << 10);
 295   meta_end = RoundUpTo(meta_end, 64 << 10);
 296   if (!data_mapped) {
 297     // First call maps data+bss.
 298     data_mapped = true;
 299     if (!MmapFixedSuperNoReserve(meta_begin, meta_end - meta_begin,
 300                                  "meta shadow"))
 301       Die();
 302   } else {
 303     // Mapping continuous heap.
 304     // Windows wants 64K alignment.
 305     meta_begin = RoundDownTo(meta_begin, 64 << 10);
 306     meta_end = RoundUpTo(meta_end, 64 << 10);
 307     if (meta_end <= mapped_meta_end)
 308       return;
 309     if (meta_begin < mapped_meta_end)
 310       meta_begin = mapped_meta_end;
 311     if (!MmapFixedSuperNoReserve(meta_begin, meta_end - meta_begin,
 312                                  "meta shadow"))
 313       Die();
 314     mapped_meta_end = meta_end;
 315   }
 316   VPrintf(2, "mapped meta shadow for (0x%zx-0x%zx) at (0x%zx-0x%zx)\n", addr,
 317           addr + size, meta_begin, meta_end);
 318 }
 319
 320 void MapThreadTrace(uptr addr, uptr size, const char *name) {
 321   DPrintf("#0: Mapping trace at 0x%zx-0x%zx(0x%zx)\n", addr, addr + size, size);
 322   CHECK_GE(addr, TraceMemBeg());
 323   CHECK_LE(addr + size, TraceMemEnd());
 324   CHECK_EQ(addr, addr & ~((64 << 10) - 1));  // windows wants 64K alignment
 325   if (!MmapFixedSuperNoReserve(addr, size, name)) {
 326     Printf("FATAL: ThreadSanitizer can not mmap thread trace (0x%zx/0x%zx)\n",
 327            addr, size);
 328     Die();
 329   }
 330 }
 331
 332 #if !SANITIZER_GO
 333 static void OnStackUnwind(const SignalContext &sig, const void *,
 334                           BufferedStackTrace *stack) {
 335   stack->Unwind(StackTrace::GetNextInstructionPc(sig.pc), sig.bp, sig.context,
 336                 common_flags()->fast_unwind_on_fatal);
 337 }
 338
 339 static void TsanOnDeadlySignal(int signo, void *siginfo, void *context) {
 340   HandleDeadlySignal(siginfo, context, GetTid(), &OnStackUnwind, nullptr);
 341 }
 342 #endif
 343
 344 void CheckUnwind() {
 345   // There is high probability that interceptors will check-fail as well,
 346   // on the other hand there is no sense in processing interceptors
 347   // since we are going to die soon.
 348   ScopedIgnoreInterceptors ignore;
 349 #if !SANITIZER_GO
 350   cur_thread()->ignore_sync++;
 351   cur_thread()->ignore_reads_and_writes++;
 352 #endif
 353   PrintCurrentStackSlow(StackTrace::GetCurrentPc());
 354 }
 355
 356 bool is_initialized;
 357
 358 void Initialize(ThreadState *thr) {
 359   // Thread safe because done before all threads exist.
 360   if (is_initialized)
 361     return;
 362   is_initialized = true;
 363   // We are not ready to handle interceptors yet.
 364   ScopedIgnoreInterceptors ignore;
 365   SanitizerToolName = "ThreadSanitizer";
 366   // Install tool-specific callbacks in sanitizer_common.
 367   SetCheckUnwindCallback(CheckUnwind);
 368
 369   ctx = new(ctx_placeholder) Context;
 370   const char *env_name = SANITIZER_GO ? "GORACE" : "TSAN_OPTIONS";
 371   const char *options = GetEnv(env_name);
 372   CacheBinaryName();
 373   CheckASLR();
 374   InitializeFlags(&ctx->flags, options, env_name);
 375   AvoidCVE_2016_2143();
 376   __sanitizer::InitializePlatformEarly();
 377   __tsan::InitializePlatformEarly();
 378
 379 #if !SANITIZER_GO
 380   // Re-exec ourselves if we need to set additional env or command line args.
 381   MaybeReexec();
 382
 383   InitializeAllocator();
 384   ReplaceSystemMalloc();
 385 #endif
 386   if (common_flags()->detect_deadlocks)
 387     ctx->dd = DDetector::Create(flags());
 388   Processor *proc = ProcCreate();
 389   ProcWire(proc, thr);
 390   InitializeInterceptors();
 391   InitializePlatform();
 392   InitializeDynamicAnnotations();
 393 #if !SANITIZER_GO
 394   InitializeShadowMemory();
 395   InitializeAllocatorLate();
 396   InstallDeadlySignalHandlers(TsanOnDeadlySignal);
 397 #endif
 398   // Setup correct file descriptor for error reports.
 399   __sanitizer_set_report_path(common_flags()->log_path);
 400   InitializeSuppressions();
 401 #if !SANITIZER_GO
 402   InitializeLibIgnore();
 403   Symbolizer::GetOrInit()->AddHooks(EnterSymbolizer, ExitSymbolizer);
 404 #endif
 405
 406   VPrintf(1, "***** Running under ThreadSanitizer v2 (pid %d) *****\n",
 407           (int)internal_getpid());
 408
 409   // Initialize thread 0.
 410   Tid tid = ThreadCreate(thr, 0, 0, true);
 411   CHECK_EQ(tid, kMainTid);
 412   ThreadStart(thr, tid, GetTid(), ThreadType::Regular);
 413 #if TSAN_CONTAINS_UBSAN
 414   __ubsan::InitAsPlugin();
 415 #endif
 416   ctx->initialized = true;
 417
 418 #if !SANITIZER_GO
 419   Symbolizer::LateInitialize();
 420   InitializeMemoryProfiler();
 421 #endif
 422
 423   if (flags()->stop_on_start) {
 424     Printf("ThreadSanitizer is suspended at startup (pid %d)."
 425            " Call __tsan_resume().\n",
 426            (int)internal_getpid());
 427     while (__tsan_resumed == 0) {}
 428   }
 429
 430   OnInitialize();
 431 }
 432
 433 void MaybeSpawnBackgroundThread() {
 434   // On MIPS, TSan initialization is run before
 435   // __pthread_initialize_minimal_internal() is finished, so we can not spawn
 436   // new threads.
 437 #if !SANITIZER_GO && !defined(__mips__)
 438   static atomic_uint32_t bg_thread = {};
 439   if (atomic_load(&bg_thread, memory_order_relaxed) == 0 &&
 440       atomic_exchange(&bg_thread, 1, memory_order_relaxed) == 0) {
 441     StartBackgroundThread();
 442     SetSandboxingCallback(StopBackgroundThread);
 443   }
 444 #endif
 445 }
 446
 447
 448 int Finalize(ThreadState *thr) {
 449   bool failed = false;
 450
 451   if (common_flags()->print_module_map == 1)
 452     DumpProcessMap();
 453
 454   if (flags()->atexit_sleep_ms > 0 && ThreadCount(thr) > 1)
 455     SleepForMillis(flags()->atexit_sleep_ms);
 456
 457   // Wait for pending reports.
 458   ctx->report_mtx.Lock();
 459   { ScopedErrorReportLock l; }
 460   ctx->report_mtx.Unlock();
 461
 462 #if !SANITIZER_GO
 463   if (Verbosity()) AllocatorPrintStats();
 464 #endif
 465
 466   ThreadFinalize(thr);
 467
 468   if (ctx->nreported) {
 469     failed = true;
 470 #if !SANITIZER_GO
 471     Printf("ThreadSanitizer: reported %d warnings\n", ctx->nreported);
 472 #else
 473     Printf("Found %d data race(s)\n", ctx->nreported);
 474 #endif
 475   }
 476
 477   if (common_flags()->print_suppressions)
 478     PrintMatchedSuppressions();
 479
 480   failed = OnFinalize(failed);
 481
 482   return failed ? common_flags()->exitcode : 0;
 483 }
 484
 485 #if !SANITIZER_GO
 486 void ForkBefore(ThreadState *thr, uptr pc) NO_THREAD_SAFETY_ANALYSIS {
 487   ctx->thread_registry.Lock();
 488   ctx->report_mtx.Lock();
 489   ScopedErrorReportLock::Lock();
 490   // Suppress all reports in the pthread_atfork callbacks.
 491   // Reports will deadlock on the report_mtx.
 492   // We could ignore sync operations as well,
 493   // but so far it's unclear if it will do more good or harm.
 494   // Unnecessarily ignoring things can lead to false positives later.
 495   thr->suppress_reports++;
 496   // On OS X, REAL(fork) can call intercepted functions (OSSpinLockLock), and
 497   // we'll assert in CheckNoLocks() unless we ignore interceptors.
 498   thr->ignore_interceptors++;
 499 }
 500
 501 void ForkParentAfter(ThreadState *thr, uptr pc) NO_THREAD_SAFETY_ANALYSIS {
 502   thr->suppress_reports--;  // Enabled in ForkBefore.
 503   thr->ignore_interceptors--;
 504   ScopedErrorReportLock::Unlock();
 505   ctx->report_mtx.Unlock();
 506   ctx->thread_registry.Unlock();
 507 }
 508
 509 void ForkChildAfter(ThreadState *thr, uptr pc,
 510                     bool start_thread) NO_THREAD_SAFETY_ANALYSIS {
 511   thr->suppress_reports--;  // Enabled in ForkBefore.
 512   thr->ignore_interceptors--;
 513   ScopedErrorReportLock::Unlock();
 514   ctx->report_mtx.Unlock();
 515   ctx->thread_registry.Unlock();
 516
 517   uptr nthread = 0;
 518   ctx->thread_registry.GetNumberOfThreads(0, 0, &nthread /* alive threads */);
 519   VPrintf(1, "ThreadSanitizer: forked new process with pid %d,"
 520       " parent had %d threads\n", (int)internal_getpid(), (int)nthread);
 521   if (nthread == 1) {
 522     if (start_thread)
 523       StartBackgroundThread();
 524   } else {
 525     // We've just forked a multi-threaded process. We cannot reasonably function
 526     // after that (some mutexes may be locked before fork). So just enable
 527     // ignores for everything in the hope that we will exec soon.
 528     ctx->after_multithreaded_fork = true;
 529     thr->ignore_interceptors++;
 530     ThreadIgnoreBegin(thr, pc);
 531     ThreadIgnoreSyncBegin(thr, pc);
 532   }
 533 }
 534 #endif
 535
 536 #if SANITIZER_GO
 537 NOINLINE
 538 void GrowShadowStack(ThreadState *thr) {
 539   const int sz = thr->shadow_stack_end - thr->shadow_stack;
 540   const int newsz = 2 * sz;
 541   auto *newstack = (uptr *)Alloc(newsz * sizeof(uptr));
 542   internal_memcpy(newstack, thr->shadow_stack, sz * sizeof(uptr));
 543   Free(thr->shadow_stack);
 544   thr->shadow_stack = newstack;
 545   thr->shadow_stack_pos = newstack + sz;
 546   thr->shadow_stack_end = newstack + newsz;
 547 }
 548 #endif
 549
 550 StackID CurrentStackId(ThreadState *thr, uptr pc) {
 551   if (!thr->is_inited)  // May happen during bootstrap.
 552     return kInvalidStackID;
 553   if (pc != 0) {
 554 #if !SANITIZER_GO
 555     DCHECK_LT(thr->shadow_stack_pos, thr->shadow_stack_end);
 556 #else
 557     if (thr->shadow_stack_pos == thr->shadow_stack_end)
 558       GrowShadowStack(thr);
 559 #endif
 560     thr->shadow_stack_pos[0] = pc;
 561     thr->shadow_stack_pos++;
 562   }
 563   StackID id = StackDepotPut(
 564       StackTrace(thr->shadow_stack, thr->shadow_stack_pos - thr->shadow_stack));
 565   if (pc != 0)
 566     thr->shadow_stack_pos--;
 567   return id;
 568 }
 569
 570 namespace v3 {
 571
 572 NOINLINE
 573 void TraceSwitchPart(ThreadState *thr) {
 574   Trace *trace = &thr->tctx->trace;
 575   Event *pos = reinterpret_cast<Event *>(atomic_load_relaxed(&thr->trace_pos));
 576   DCHECK_EQ(reinterpret_cast<uptr>(pos + 1) & TracePart::kAlignment, 0);
 577   auto *part = trace->parts.Back();
 578   DPrintf("TraceSwitchPart part=%p pos=%p\n", part, pos);
 579   if (part) {
 580     // We can get here when we still have space in the current trace part.
 581     // The fast-path check in TraceAcquire has false positives in the middle of
 582     // the part. Check if we are indeed at the end of the current part or not,
 583     // and fill any gaps with NopEvent's.
 584     Event *end = &part->events[TracePart::kSize];
 585     DCHECK_GE(pos, &part->events[0]);
 586     DCHECK_LE(pos, end);
 587     if (pos + 1 < end) {
 588       if ((reinterpret_cast<uptr>(pos) & TracePart::kAlignment) ==
 589           TracePart::kAlignment)
 590         *pos++ = NopEvent;
 591       *pos++ = NopEvent;
 592       DCHECK_LE(pos + 2, end);
 593       atomic_store_relaxed(&thr->trace_pos, reinterpret_cast<uptr>(pos));
 594       // Ensure we setup trace so that the next TraceAcquire
 595       // won't detect trace part end.
 596       Event *ev;
 597       CHECK(TraceAcquire(thr, &ev));
 598       return;
 599     }
 600     // We are indeed at the end.
 601     for (; pos < end; pos++) *pos = NopEvent;
 602   }
 603 #if !SANITIZER_GO
 604   if (ctx->after_multithreaded_fork) {
 605     // We just need to survive till exec.
 606     CHECK(part);
 607     atomic_store_relaxed(&thr->trace_pos,
 608                          reinterpret_cast<uptr>(&part->events[0]));
 609     return;
 610   }
 611 #endif
 612   part = new (MmapOrDie(sizeof(TracePart), "TracePart")) TracePart();
 613   part->trace = trace;
 614   thr->trace_prev_pc = 0;
 615   {
 616     Lock lock(&trace->mtx);
 617     trace->parts.PushBack(part);
 618     atomic_store_relaxed(&thr->trace_pos,
 619                          reinterpret_cast<uptr>(&part->events[0]));
 620   }
 621   // Make this part self-sufficient by restoring the current stack
 622   // and mutex set in the beginning of the trace.
 623   TraceTime(thr);
 624   for (uptr *pos = &thr->shadow_stack[0]; pos < thr->shadow_stack_pos; pos++)
 625     CHECK(TryTraceFunc(thr, *pos));
 626   for (uptr i = 0; i < thr->mset.Size(); i++) {
 627     MutexSet::Desc d = thr->mset.Get(i);
 628     TraceMutexLock(thr, d.write ? EventType::kLock : EventType::kRLock, 0,
 629                    d.addr, d.stack_id);
 630   }
 631 }
 632
 633 }  // namespace v3
 634
 635 void TraceSwitch(ThreadState *thr) {
 636 #if !SANITIZER_GO
 637   if (ctx->after_multithreaded_fork)
 638     return;
 639 #endif
 640   thr->nomalloc++;
 641   Trace *thr_trace = ThreadTrace(thr->tid);
 642   Lock l(&thr_trace->mtx);
 643   unsigned trace = (thr->fast_state.epoch() / kTracePartSize) % TraceParts();
 644   TraceHeader *hdr = &thr_trace->headers[trace];
 645   hdr->epoch0 = thr->fast_state.epoch();
 646   ObtainCurrentStack(thr, 0, &hdr->stack0);
 647   hdr->mset0 = thr->mset;
 648   thr->nomalloc--;
 649 }
 650
 651 Trace *ThreadTrace(Tid tid) { return (Trace *)GetThreadTraceHeader(tid); }
 652
 653 uptr TraceTopPC(ThreadState *thr) {
 654   Event *events = (Event*)GetThreadTrace(thr->tid);
 655   uptr pc = events[thr->fast_state.GetTracePos()];
 656   return pc;
 657 }
 658
 659 uptr TraceSize() {
 660   return (uptr)(1ull << (kTracePartSizeBits + flags()->history_size + 1));
 661 }
 662
 663 uptr TraceParts() {
 664   return TraceSize() / kTracePartSize;
 665 }
 666
 667 #if !SANITIZER_GO
 668 extern "C" void __tsan_trace_switch() {
 669   TraceSwitch(cur_thread());
 670 }
 671
 672 extern "C" void __tsan_report_race() {
 673   ReportRace(cur_thread());
 674 }
 675 #endif
 676
 677 void ThreadIgnoreBegin(ThreadState *thr, uptr pc) {
 678   DPrintf("#%d: ThreadIgnoreBegin\n", thr->tid);
 679   thr->ignore_reads_and_writes++;
 680   CHECK_GT(thr->ignore_reads_and_writes, 0);
 681   thr->fast_state.SetIgnoreBit();
 682 #if !SANITIZER_GO
 683   if (pc && !ctx->after_multithreaded_fork)
 684     thr->mop_ignore_set.Add(CurrentStackId(thr, pc));
 685 #endif
 686 }
 687
 688 void ThreadIgnoreEnd(ThreadState *thr) {
 689   DPrintf("#%d: ThreadIgnoreEnd\n", thr->tid);
 690   CHECK_GT(thr->ignore_reads_and_writes, 0);
 691   thr->ignore_reads_and_writes--;
 692   if (thr->ignore_reads_and_writes == 0) {
 693     thr->fast_state.ClearIgnoreBit();
 694 #if !SANITIZER_GO
 695     thr->mop_ignore_set.Reset();
 696 #endif
 697   }
 698 }
 699
 700 #if !SANITIZER_GO
 701 extern "C" SANITIZER_INTERFACE_ATTRIBUTE
 702 uptr __tsan_testonly_shadow_stack_current_size() {
 703   ThreadState *thr = cur_thread();
 704   return thr->shadow_stack_pos - thr->shadow_stack;
 705 }
 706 #endif
 707
 708 void ThreadIgnoreSyncBegin(ThreadState *thr, uptr pc) {
 709   DPrintf("#%d: ThreadIgnoreSyncBegin\n", thr->tid);
 710   thr->ignore_sync++;
 711   CHECK_GT(thr->ignore_sync, 0);
 712 #if !SANITIZER_GO
 713   if (pc && !ctx->after_multithreaded_fork)
 714     thr->sync_ignore_set.Add(CurrentStackId(thr, pc));
 715 #endif
 716 }
 717
 718 void ThreadIgnoreSyncEnd(ThreadState *thr) {
 719   DPrintf("#%d: ThreadIgnoreSyncEnd\n", thr->tid);
 720   CHECK_GT(thr->ignore_sync, 0);
 721   thr->ignore_sync--;
 722 #if !SANITIZER_GO
 723   if (thr->ignore_sync == 0)
 724     thr->sync_ignore_set.Reset();
 725 #endif
 726 }
 727
 728 bool MD5Hash::operator==(const MD5Hash &other) const {
 729   return hash[0] == other.hash[0] && hash[1] == other.hash[1];
 730 }
 731
 732 #if SANITIZER_DEBUG
 733 void build_consistency_debug() {}
 734 #else
 735 void build_consistency_release() {}
 736 #endif
 737
 738 }  // namespace __tsan
 739
 740 #if SANITIZER_CHECK_DEADLOCKS
 741 namespace __sanitizer {
 742 using namespace __tsan;
 743 MutexMeta mutex_meta[] = {
 744     {MutexInvalid, "Invalid", {}},
 745     {MutexThreadRegistry, "ThreadRegistry", {}},
 746     {MutexTypeTrace, "Trace", {MutexLeaf}},
 747     {MutexTypeReport, "Report", {MutexTypeSyncVar}},
 748     {MutexTypeSyncVar, "SyncVar", {}},
 749     {MutexTypeAnnotations, "Annotations", {}},
 750     {MutexTypeAtExit, "AtExit", {MutexTypeSyncVar}},
 751     {MutexTypeFired, "Fired", {MutexLeaf}},
 752     {MutexTypeRacy, "Racy", {MutexLeaf}},
 753     {MutexTypeGlobalProc, "GlobalProc", {}},
 754     {},
 755 };
 756
 757 void PrintMutexPC(uptr pc) { StackTrace(&pc, 1).Print(); }
 758 }  // namespace __sanitizer
 759 #endif