libsanitizer/tsan/tsan_rtl_report.cc

   1 //===-- tsan_rtl_report.cc ------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of ThreadSanitizer (TSan), a race detector.
   9 //
  10 //===----------------------------------------------------------------------===//
  11
  12 #include "sanitizer_common/sanitizer_libc.h"
  13 #include "sanitizer_common/sanitizer_placement_new.h"
  14 #include "sanitizer_common/sanitizer_stackdepot.h"
  15 #include "sanitizer_common/sanitizer_common.h"
  16 #include "sanitizer_common/sanitizer_stacktrace.h"
  17 #include "tsan_platform.h"
  18 #include "tsan_rtl.h"
  19 #include "tsan_suppressions.h"
  20 #include "tsan_symbolize.h"
  21 #include "tsan_report.h"
  22 #include "tsan_sync.h"
  23 #include "tsan_mman.h"
  24 #include "tsan_flags.h"
  25 #include "tsan_fd.h"
  26
  27 namespace __tsan {
  28
  29 using namespace __sanitizer;  // NOLINT
  30
  31 static ReportStack *SymbolizeStack(StackTrace trace);
  32
  33 void TsanCheckFailed(const char *file, int line, const char *cond,
  34                      u64 v1, u64 v2) {
  35   // There is high probability that interceptors will check-fail as well,
  36   // on the other hand there is no sense in processing interceptors
  37   // since we are going to die soon.
  38   ScopedIgnoreInterceptors ignore;
  39 #if !SANITIZER_GO
  40   cur_thread()->ignore_sync++;
  41   cur_thread()->ignore_reads_and_writes++;
  42 #endif
  43   Printf("FATAL: ThreadSanitizer CHECK failed: "
  44          "%s:%d \"%s\" (0x%zx, 0x%zx)\n",
  45          file, line, cond, (uptr)v1, (uptr)v2);
  46   PrintCurrentStackSlow(StackTrace::GetCurrentPc());
  47   Die();
  48 }
  49
  50 // Can be overriden by an application/test to intercept reports.
  51 #ifdef TSAN_EXTERNAL_HOOKS
  52 bool OnReport(const ReportDesc *rep, bool suppressed);
  53 #else
  54 SANITIZER_WEAK_CXX_DEFAULT_IMPL
  55 bool OnReport(const ReportDesc *rep, bool suppressed) {
  56   (void)rep;
  57   return suppressed;
  58 }
  59 #endif
  60
  61 SANITIZER_WEAK_DEFAULT_IMPL
  62 void __tsan_on_report(const ReportDesc *rep) {
  63   (void)rep;
  64 }
  65
  66 static void StackStripMain(SymbolizedStack *frames) {
  67   SymbolizedStack *last_frame = nullptr;
  68   SymbolizedStack *last_frame2 = nullptr;
  69   for (SymbolizedStack *cur = frames; cur; cur = cur->next) {
  70     last_frame2 = last_frame;
  71     last_frame = cur;
  72   }
  73
  74   if (last_frame2 == 0)
  75     return;
  76 #if !SANITIZER_GO
  77   const char *last = last_frame->info.function;
  78   const char *last2 = last_frame2->info.function;
  79   // Strip frame above 'main'
  80   if (last2 && 0 == internal_strcmp(last2, "main")) {
  81     last_frame->ClearAll();
  82     last_frame2->next = nullptr;
  83   // Strip our internal thread start routine.
  84   } else if (last && 0 == internal_strcmp(last, "__tsan_thread_start_func")) {
  85     last_frame->ClearAll();
  86     last_frame2->next = nullptr;
  87   // Strip global ctors init.
  88   } else if (last && 0 == internal_strcmp(last, "__do_global_ctors_aux")) {
  89     last_frame->ClearAll();
  90     last_frame2->next = nullptr;
  91   // If both are 0, then we probably just failed to symbolize.
  92   } else if (last || last2) {
  93     // Ensure that we recovered stack completely. Trimmed stack
  94     // can actually happen if we do not instrument some code,
  95     // so it's only a debug print. However we must try hard to not miss it
  96     // due to our fault.
  97     DPrintf("Bottom stack frame is missed\n");
  98   }
  99 #else
 100   // The last frame always point into runtime (gosched0, goexit0, runtime.main).
 101   last_frame->ClearAll();
 102   last_frame2->next = nullptr;
 103 #endif
 104 }
 105
 106 ReportStack *SymbolizeStackId(u32 stack_id) {
 107   if (stack_id == 0)
 108     return 0;
 109   StackTrace stack = StackDepotGet(stack_id);
 110   if (stack.trace == nullptr)
 111     return nullptr;
 112   return SymbolizeStack(stack);
 113 }
 114
 115 static ReportStack *SymbolizeStack(StackTrace trace) {
 116   if (trace.size == 0)
 117     return 0;
 118   SymbolizedStack *top = nullptr;
 119   for (uptr si = 0; si < trace.size; si++) {
 120     const uptr pc = trace.trace[si];
 121     uptr pc1 = pc;
 122     // We obtain the return address, but we're interested in the previous
 123     // instruction.
 124     if ((pc & kExternalPCBit) == 0)
 125       pc1 = StackTrace::GetPreviousInstructionPc(pc);
 126     SymbolizedStack *ent = SymbolizeCode(pc1);
 127     CHECK_NE(ent, 0);
 128     SymbolizedStack *last = ent;
 129     while (last->next) {
 130       last->info.address = pc;  // restore original pc for report
 131       last = last->next;
 132     }
 133     last->info.address = pc;  // restore original pc for report
 134     last->next = top;
 135     top = ent;
 136   }
 137   StackStripMain(top);
 138
 139   ReportStack *stack = ReportStack::New();
 140   stack->frames = top;
 141   return stack;
 142 }
 143
 144 ScopedReport::ScopedReport(ReportType typ) {
 145   ctx->thread_registry->CheckLocked();
 146   void *mem = internal_alloc(MBlockReport, sizeof(ReportDesc));
 147   rep_ = new(mem) ReportDesc;
 148   rep_->typ = typ;
 149   ctx->report_mtx.Lock();
 150   CommonSanitizerReportMutex.Lock();
 151 }
 152
 153 ScopedReport::~ScopedReport() {
 154   CommonSanitizerReportMutex.Unlock();
 155   ctx->report_mtx.Unlock();
 156   DestroyAndFree(rep_);
 157 }
 158
 159 void ScopedReport::AddStack(StackTrace stack, bool suppressable) {
 160   ReportStack **rs = rep_->stacks.PushBack();
 161   *rs = SymbolizeStack(stack);
 162   (*rs)->suppressable = suppressable;
 163 }
 164
 165 void ScopedReport::AddMemoryAccess(uptr addr, Shadow s, StackTrace stack,
 166                                    const MutexSet *mset) {
 167   void *mem = internal_alloc(MBlockReportMop, sizeof(ReportMop));
 168   ReportMop *mop = new(mem) ReportMop;
 169   rep_->mops.PushBack(mop);
 170   mop->tid = s.tid();
 171   mop->addr = addr + s.addr0();
 172   mop->size = s.size();
 173   mop->write = s.IsWrite();
 174   mop->atomic = s.IsAtomic();
 175   mop->stack = SymbolizeStack(stack);
 176   if (mop->stack)
 177     mop->stack->suppressable = true;
 178   for (uptr i = 0; i < mset->Size(); i++) {
 179     MutexSet::Desc d = mset->Get(i);
 180     u64 mid = this->AddMutex(d.id);
 181     ReportMopMutex mtx = {mid, d.write};
 182     mop->mset.PushBack(mtx);
 183   }
 184 }
 185
 186 void ScopedReport::AddUniqueTid(int unique_tid) {
 187   rep_->unique_tids.PushBack(unique_tid);
 188 }
 189
 190 void ScopedReport::AddThread(const ThreadContext *tctx, bool suppressable) {
 191   for (uptr i = 0; i < rep_->threads.Size(); i++) {
 192     if ((u32)rep_->threads[i]->id == tctx->tid)
 193       return;
 194   }
 195   void *mem = internal_alloc(MBlockReportThread, sizeof(ReportThread));
 196   ReportThread *rt = new(mem) ReportThread;
 197   rep_->threads.PushBack(rt);
 198   rt->id = tctx->tid;
 199   rt->os_id = tctx->os_id;
 200   rt->running = (tctx->status == ThreadStatusRunning);
 201   rt->name = internal_strdup(tctx->name);
 202   rt->parent_tid = tctx->parent_tid;
 203   rt->stack = 0;
 204   rt->stack = SymbolizeStackId(tctx->creation_stack_id);
 205   if (rt->stack)
 206     rt->stack->suppressable = suppressable;
 207 }
 208
 209 #if !SANITIZER_GO
 210 static bool FindThreadByUidLockedCallback(ThreadContextBase *tctx, void *arg) {
 211   int unique_id = *(int *)arg;
 212   return tctx->unique_id == (u32)unique_id;
 213 }
 214
 215 static ThreadContext *FindThreadByUidLocked(int unique_id) {
 216   ctx->thread_registry->CheckLocked();
 217   return static_cast<ThreadContext *>(
 218       ctx->thread_registry->FindThreadContextLocked(
 219           FindThreadByUidLockedCallback, &unique_id));
 220 }
 221
 222 static ThreadContext *FindThreadByTidLocked(int tid) {
 223   ctx->thread_registry->CheckLocked();
 224   return static_cast<ThreadContext*>(
 225       ctx->thread_registry->GetThreadLocked(tid));
 226 }
 227
 228 static bool IsInStackOrTls(ThreadContextBase *tctx_base, void *arg) {
 229   uptr addr = (uptr)arg;
 230   ThreadContext *tctx = static_cast<ThreadContext*>(tctx_base);
 231   if (tctx->status != ThreadStatusRunning)
 232     return false;
 233   ThreadState *thr = tctx->thr;
 234   CHECK(thr);
 235   return ((addr >= thr->stk_addr && addr < thr->stk_addr + thr->stk_size) ||
 236           (addr >= thr->tls_addr && addr < thr->tls_addr + thr->tls_size));
 237 }
 238
 239 ThreadContext *IsThreadStackOrTls(uptr addr, bool *is_stack) {
 240   ctx->thread_registry->CheckLocked();
 241   ThreadContext *tctx = static_cast<ThreadContext*>(
 242       ctx->thread_registry->FindThreadContextLocked(IsInStackOrTls,
 243                                                     (void*)addr));
 244   if (!tctx)
 245     return 0;
 246   ThreadState *thr = tctx->thr;
 247   CHECK(thr);
 248   *is_stack = (addr >= thr->stk_addr && addr < thr->stk_addr + thr->stk_size);
 249   return tctx;
 250 }
 251 #endif
 252
 253 void ScopedReport::AddThread(int unique_tid, bool suppressable) {
 254 #if !SANITIZER_GO
 255   if (const ThreadContext *tctx = FindThreadByUidLocked(unique_tid))
 256     AddThread(tctx, suppressable);
 257 #endif
 258 }
 259
 260 void ScopedReport::AddMutex(const SyncVar *s) {
 261   for (uptr i = 0; i < rep_->mutexes.Size(); i++) {
 262     if (rep_->mutexes[i]->id == s->uid)
 263       return;
 264   }
 265   void *mem = internal_alloc(MBlockReportMutex, sizeof(ReportMutex));
 266   ReportMutex *rm = new(mem) ReportMutex;
 267   rep_->mutexes.PushBack(rm);
 268   rm->id = s->uid;
 269   rm->addr = s->addr;
 270   rm->destroyed = false;
 271   rm->stack = SymbolizeStackId(s->creation_stack_id);
 272 }
 273
 274 u64 ScopedReport::AddMutex(u64 id) {
 275   u64 uid = 0;
 276   u64 mid = id;
 277   uptr addr = SyncVar::SplitId(id, &uid);
 278   SyncVar *s = ctx->metamap.GetIfExistsAndLock(addr, true);
 279   // Check that the mutex is still alive.
 280   // Another mutex can be created at the same address,
 281   // so check uid as well.
 282   if (s && s->CheckId(uid)) {
 283     mid = s->uid;
 284     AddMutex(s);
 285   } else {
 286     AddDeadMutex(id);
 287   }
 288   if (s)
 289     s->mtx.Unlock();
 290   return mid;
 291 }
 292
 293 void ScopedReport::AddDeadMutex(u64 id) {
 294   for (uptr i = 0; i < rep_->mutexes.Size(); i++) {
 295     if (rep_->mutexes[i]->id == id)
 296       return;
 297   }
 298   void *mem = internal_alloc(MBlockReportMutex, sizeof(ReportMutex));
 299   ReportMutex *rm = new(mem) ReportMutex;
 300   rep_->mutexes.PushBack(rm);
 301   rm->id = id;
 302   rm->addr = 0;
 303   rm->destroyed = true;
 304   rm->stack = 0;
 305 }
 306
 307 void ScopedReport::AddLocation(uptr addr, uptr size) {
 308   if (addr == 0)
 309     return;
 310 #if !SANITIZER_GO
 311   int fd = -1;
 312   int creat_tid = -1;
 313   u32 creat_stack = 0;
 314   if (FdLocation(addr, &fd, &creat_tid, &creat_stack)) {
 315     ReportLocation *loc = ReportLocation::New(ReportLocationFD);
 316     loc->fd = fd;
 317     loc->tid = creat_tid;
 318     loc->stack = SymbolizeStackId(creat_stack);
 319     rep_->locs.PushBack(loc);
 320     ThreadContext *tctx = FindThreadByUidLocked(creat_tid);
 321     if (tctx)
 322       AddThread(tctx);
 323     return;
 324   }
 325   MBlock *b = 0;
 326   Allocator *a = allocator();
 327   if (a->PointerIsMine((void*)addr)) {
 328     void *block_begin = a->GetBlockBegin((void*)addr);
 329     if (block_begin)
 330       b = ctx->metamap.GetBlock((uptr)block_begin);
 331   }
 332   if (b != 0) {
 333     ThreadContext *tctx = FindThreadByTidLocked(b->tid);
 334     ReportLocation *loc = ReportLocation::New(ReportLocationHeap);
 335     loc->heap_chunk_start = (uptr)allocator()->GetBlockBegin((void *)addr);
 336     loc->heap_chunk_size = b->siz;
 337     loc->tid = tctx ? tctx->tid : b->tid;
 338     loc->stack = SymbolizeStackId(b->stk);
 339     rep_->locs.PushBack(loc);
 340     if (tctx)
 341       AddThread(tctx);
 342     return;
 343   }
 344   bool is_stack = false;
 345   if (ThreadContext *tctx = IsThreadStackOrTls(addr, &is_stack)) {
 346     ReportLocation *loc =
 347         ReportLocation::New(is_stack ? ReportLocationStack : ReportLocationTLS);
 348     loc->tid = tctx->tid;
 349     rep_->locs.PushBack(loc);
 350     AddThread(tctx);
 351   }
 352 #endif
 353   if (ReportLocation *loc = SymbolizeData(addr)) {
 354     loc->suppressable = true;
 355     rep_->locs.PushBack(loc);
 356     return;
 357   }
 358 }
 359
 360 #if !SANITIZER_GO
 361 void ScopedReport::AddSleep(u32 stack_id) {
 362   rep_->sleep = SymbolizeStackId(stack_id);
 363 }
 364 #endif
 365
 366 void ScopedReport::SetCount(int count) {
 367   rep_->count = count;
 368 }
 369
 370 const ReportDesc *ScopedReport::GetReport() const {
 371   return rep_;
 372 }
 373
 374 void RestoreStack(int tid, const u64 epoch, VarSizeStackTrace *stk,
 375                   MutexSet *mset) {
 376   // This function restores stack trace and mutex set for the thread/epoch.
 377   // It does so by getting stack trace and mutex set at the beginning of
 378   // trace part, and then replaying the trace till the given epoch.
 379   Trace* trace = ThreadTrace(tid);
 380   ReadLock l(&trace->mtx);
 381   const int partidx = (epoch / kTracePartSize) % TraceParts();
 382   TraceHeader* hdr = &trace->headers[partidx];
 383   if (epoch < hdr->epoch0 || epoch >= hdr->epoch0 + kTracePartSize)
 384     return;
 385   CHECK_EQ(RoundDown(epoch, kTracePartSize), hdr->epoch0);
 386   const u64 epoch0 = RoundDown(epoch, TraceSize());
 387   const u64 eend = epoch % TraceSize();
 388   const u64 ebegin = RoundDown(eend, kTracePartSize);
 389   DPrintf("#%d: RestoreStack epoch=%zu ebegin=%zu eend=%zu partidx=%d\n",
 390           tid, (uptr)epoch, (uptr)ebegin, (uptr)eend, partidx);
 391   Vector<uptr> stack(MBlockReportStack);
 392   stack.Resize(hdr->stack0.size + 64);
 393   for (uptr i = 0; i < hdr->stack0.size; i++) {
 394     stack[i] = hdr->stack0.trace[i];
 395     DPrintf2("  #%02zu: pc=%zx\n", i, stack[i]);
 396   }
 397   if (mset)
 398     *mset = hdr->mset0;
 399   uptr pos = hdr->stack0.size;
 400   Event *events = (Event*)GetThreadTrace(tid);
 401   for (uptr i = ebegin; i <= eend; i++) {
 402     Event ev = events[i];
 403     EventType typ = (EventType)(ev >> 61);
 404     uptr pc = (uptr)(ev & ((1ull << 61) - 1));
 405     DPrintf2("  %zu typ=%d pc=%zx\n", i, typ, pc);
 406     if (typ == EventTypeMop) {
 407       stack[pos] = pc;
 408     } else if (typ == EventTypeFuncEnter) {
 409       if (stack.Size() < pos + 2)
 410         stack.Resize(pos + 2);
 411       stack[pos++] = pc;
 412     } else if (typ == EventTypeFuncExit) {
 413       if (pos > 0)
 414         pos--;
 415     }
 416     if (mset) {
 417       if (typ == EventTypeLock) {
 418         mset->Add(pc, true, epoch0 + i);
 419       } else if (typ == EventTypeUnlock) {
 420         mset->Del(pc, true);
 421       } else if (typ == EventTypeRLock) {
 422         mset->Add(pc, false, epoch0 + i);
 423       } else if (typ == EventTypeRUnlock) {
 424         mset->Del(pc, false);
 425       }
 426     }
 427     for (uptr j = 0; j <= pos; j++)
 428       DPrintf2("      #%zu: %zx\n", j, stack[j]);
 429   }
 430   if (pos == 0 && stack[0] == 0)
 431     return;
 432   pos++;
 433   stk->Init(&stack[0], pos);
 434 }
 435
 436 static bool HandleRacyStacks(ThreadState *thr, VarSizeStackTrace traces[2],
 437                              uptr addr_min, uptr addr_max) {
 438   bool equal_stack = false;
 439   RacyStacks hash;
 440   bool equal_address = false;
 441   RacyAddress ra0 = {addr_min, addr_max};
 442   {
 443     ReadLock lock(&ctx->racy_mtx);
 444     if (flags()->suppress_equal_stacks) {
 445       hash.hash[0] = md5_hash(traces[0].trace, traces[0].size * sizeof(uptr));
 446       hash.hash[1] = md5_hash(traces[1].trace, traces[1].size * sizeof(uptr));
 447       for (uptr i = 0; i < ctx->racy_stacks.Size(); i++) {
 448         if (hash == ctx->racy_stacks[i]) {
 449           VPrintf(2,
 450               "ThreadSanitizer: suppressing report as doubled (stack)\n");
 451           equal_stack = true;
 452           break;
 453         }
 454       }
 455     }
 456     if (flags()->suppress_equal_addresses) {
 457       for (uptr i = 0; i < ctx->racy_addresses.Size(); i++) {
 458         RacyAddress ra2 = ctx->racy_addresses[i];
 459         uptr maxbeg = max(ra0.addr_min, ra2.addr_min);
 460         uptr minend = min(ra0.addr_max, ra2.addr_max);
 461         if (maxbeg < minend) {
 462           VPrintf(2, "ThreadSanitizer: suppressing report as doubled (addr)\n");
 463           equal_address = true;
 464           break;
 465         }
 466       }
 467     }
 468   }
 469   if (!equal_stack && !equal_address)
 470     return false;
 471   if (!equal_stack) {
 472     Lock lock(&ctx->racy_mtx);
 473     ctx->racy_stacks.PushBack(hash);
 474   }
 475   if (!equal_address) {
 476     Lock lock(&ctx->racy_mtx);
 477     ctx->racy_addresses.PushBack(ra0);
 478   }
 479   return true;
 480 }
 481
 482 static void AddRacyStacks(ThreadState *thr, VarSizeStackTrace traces[2],
 483                           uptr addr_min, uptr addr_max) {
 484   Lock lock(&ctx->racy_mtx);
 485   if (flags()->suppress_equal_stacks) {
 486     RacyStacks hash;
 487     hash.hash[0] = md5_hash(traces[0].trace, traces[0].size * sizeof(uptr));
 488     hash.hash[1] = md5_hash(traces[1].trace, traces[1].size * sizeof(uptr));
 489     ctx->racy_stacks.PushBack(hash);
 490   }
 491   if (flags()->suppress_equal_addresses) {
 492     RacyAddress ra0 = {addr_min, addr_max};
 493     ctx->racy_addresses.PushBack(ra0);
 494   }
 495 }
 496
 497 bool OutputReport(ThreadState *thr, const ScopedReport &srep) {
 498   if (!flags()->report_bugs)
 499     return false;
 500   atomic_store_relaxed(&ctx->last_symbolize_time_ns, NanoTime());
 501   const ReportDesc *rep = srep.GetReport();
 502   CHECK_EQ(thr->current_report, nullptr);
 503   thr->current_report = rep;
 504   Suppression *supp = 0;
 505   uptr pc_or_addr = 0;
 506   for (uptr i = 0; pc_or_addr == 0 && i < rep->mops.Size(); i++)
 507     pc_or_addr = IsSuppressed(rep->typ, rep->mops[i]->stack, &supp);
 508   for (uptr i = 0; pc_or_addr == 0 && i < rep->stacks.Size(); i++)
 509     pc_or_addr = IsSuppressed(rep->typ, rep->stacks[i], &supp);
 510   for (uptr i = 0; pc_or_addr == 0 && i < rep->threads.Size(); i++)
 511     pc_or_addr = IsSuppressed(rep->typ, rep->threads[i]->stack, &supp);
 512   for (uptr i = 0; pc_or_addr == 0 && i < rep->locs.Size(); i++)
 513     pc_or_addr = IsSuppressed(rep->typ, rep->locs[i], &supp);
 514   if (pc_or_addr != 0) {
 515     Lock lock(&ctx->fired_suppressions_mtx);
 516     FiredSuppression s = {srep.GetReport()->typ, pc_or_addr, supp};
 517     ctx->fired_suppressions.push_back(s);
 518   }
 519   {
 520     bool old_is_freeing = thr->is_freeing;
 521     thr->is_freeing = false;
 522     bool suppressed = OnReport(rep, pc_or_addr != 0);
 523     thr->is_freeing = old_is_freeing;
 524     if (suppressed) {
 525       thr->current_report = nullptr;
 526       return false;
 527     }
 528   }
 529   PrintReport(rep);
 530   __tsan_on_report(rep);
 531   ctx->nreported++;
 532   if (flags()->halt_on_error)
 533     Die();
 534   thr->current_report = nullptr;
 535   return true;
 536 }
 537
 538 bool IsFiredSuppression(Context *ctx, ReportType type, StackTrace trace) {
 539   ReadLock lock(&ctx->fired_suppressions_mtx);
 540   for (uptr k = 0; k < ctx->fired_suppressions.size(); k++) {
 541     if (ctx->fired_suppressions[k].type != type)
 542       continue;
 543     for (uptr j = 0; j < trace.size; j++) {
 544       FiredSuppression *s = &ctx->fired_suppressions[k];
 545       if (trace.trace[j] == s->pc_or_addr) {
 546         if (s->supp)
 547           atomic_fetch_add(&s->supp->hit_count, 1, memory_order_relaxed);
 548         return true;
 549       }
 550     }
 551   }
 552   return false;
 553 }
 554
 555 static bool IsFiredSuppression(Context *ctx, ReportType type, uptr addr) {
 556   ReadLock lock(&ctx->fired_suppressions_mtx);
 557   for (uptr k = 0; k < ctx->fired_suppressions.size(); k++) {
 558     if (ctx->fired_suppressions[k].type != type)
 559       continue;
 560     FiredSuppression *s = &ctx->fired_suppressions[k];
 561     if (addr == s->pc_or_addr) {
 562       if (s->supp)
 563         atomic_fetch_add(&s->supp->hit_count, 1, memory_order_relaxed);
 564       return true;
 565     }
 566   }
 567   return false;
 568 }
 569
 570 static bool RaceBetweenAtomicAndFree(ThreadState *thr) {
 571   Shadow s0(thr->racy_state[0]);
 572   Shadow s1(thr->racy_state[1]);
 573   CHECK(!(s0.IsAtomic() && s1.IsAtomic()));
 574   if (!s0.IsAtomic() && !s1.IsAtomic())
 575     return true;
 576   if (s0.IsAtomic() && s1.IsFreed())
 577     return true;
 578   if (s1.IsAtomic() && thr->is_freeing)
 579     return true;
 580   return false;
 581 }
 582
 583 void ReportRace(ThreadState *thr) {
 584   CheckNoLocks(thr);
 585
 586   // Symbolizer makes lots of intercepted calls. If we try to process them,
 587   // at best it will cause deadlocks on internal mutexes.
 588   ScopedIgnoreInterceptors ignore;
 589
 590   if (!flags()->report_bugs)
 591     return;
 592   if (!flags()->report_atomic_races && !RaceBetweenAtomicAndFree(thr))
 593     return;
 594
 595   bool freed = false;
 596   {
 597     Shadow s(thr->racy_state[1]);
 598     freed = s.GetFreedAndReset();
 599     thr->racy_state[1] = s.raw();
 600   }
 601
 602   uptr addr = ShadowToMem((uptr)thr->racy_shadow_addr);
 603   uptr addr_min = 0;
 604   uptr addr_max = 0;
 605   {
 606     uptr a0 = addr + Shadow(thr->racy_state[0]).addr0();
 607     uptr a1 = addr + Shadow(thr->racy_state[1]).addr0();
 608     uptr e0 = a0 + Shadow(thr->racy_state[0]).size();
 609     uptr e1 = a1 + Shadow(thr->racy_state[1]).size();
 610     addr_min = min(a0, a1);
 611     addr_max = max(e0, e1);
 612     if (IsExpectedReport(addr_min, addr_max - addr_min))
 613       return;
 614   }
 615
 616   ReportType typ = ReportTypeRace;
 617   if (thr->is_vptr_access && freed)
 618     typ = ReportTypeVptrUseAfterFree;
 619   else if (thr->is_vptr_access)
 620     typ = ReportTypeVptrRace;
 621   else if (freed)
 622     typ = ReportTypeUseAfterFree;
 623
 624   if (IsFiredSuppression(ctx, typ, addr))
 625     return;
 626
 627   const uptr kMop = 2;
 628   VarSizeStackTrace traces[kMop];
 629   const uptr toppc = TraceTopPC(thr);
 630   ObtainCurrentStack(thr, toppc, &traces[0]);
 631   if (IsFiredSuppression(ctx, typ, traces[0]))
 632     return;
 633
 634   // MutexSet is too large to live on stack.
 635   Vector<u64> mset_buffer(MBlockScopedBuf);
 636   mset_buffer.Resize(sizeof(MutexSet) / sizeof(u64) + 1);
 637   MutexSet *mset2 = new(&mset_buffer[0]) MutexSet();
 638
 639   Shadow s2(thr->racy_state[1]);
 640   RestoreStack(s2.tid(), s2.epoch(), &traces[1], mset2);
 641   if (IsFiredSuppression(ctx, typ, traces[1]))
 642     return;
 643
 644   if (HandleRacyStacks(thr, traces, addr_min, addr_max))
 645     return;
 646
 647   ThreadRegistryLock l0(ctx->thread_registry);
 648   ScopedReport rep(typ);
 649   for (uptr i = 0; i < kMop; i++) {
 650     Shadow s(thr->racy_state[i]);
 651     rep.AddMemoryAccess(addr, s, traces[i], i == 0 ? &thr->mset : mset2);
 652   }
 653
 654   for (uptr i = 0; i < kMop; i++) {
 655     FastState s(thr->racy_state[i]);
 656     ThreadContext *tctx = static_cast<ThreadContext*>(
 657         ctx->thread_registry->GetThreadLocked(s.tid()));
 658     if (s.epoch() < tctx->epoch0 || s.epoch() > tctx->epoch1)
 659       continue;
 660     rep.AddThread(tctx);
 661   }
 662
 663   rep.AddLocation(addr_min, addr_max - addr_min);
 664
 665 #if !SANITIZER_GO
 666   {  // NOLINT
 667     Shadow s(thr->racy_state[1]);
 668     if (s.epoch() <= thr->last_sleep_clock.get(s.tid()))
 669       rep.AddSleep(thr->last_sleep_stack_id);
 670   }
 671 #endif
 672
 673   if (!OutputReport(thr, rep))
 674     return;
 675
 676   AddRacyStacks(thr, traces, addr_min, addr_max);
 677 }
 678
 679 void PrintCurrentStack(ThreadState *thr, uptr pc) {
 680   VarSizeStackTrace trace;
 681   ObtainCurrentStack(thr, pc, &trace);
 682   PrintStack(SymbolizeStack(trace));
 683 }
 684
 685 // Always inlining PrintCurrentStackSlow, because LocatePcInTrace assumes
 686 // __sanitizer_print_stack_trace exists in the actual unwinded stack, but
 687 // tail-call to PrintCurrentStackSlow breaks this assumption because
 688 // __sanitizer_print_stack_trace disappears after tail-call.
 689 // However, this solution is not reliable enough, please see dvyukov's comment
 690 // http://reviews.llvm.org/D19148#406208
 691 // Also see PR27280 comment 2 and 3 for breaking examples and analysis.
 692 ALWAYS_INLINE
 693 void PrintCurrentStackSlow(uptr pc) {
 694 #if !SANITIZER_GO
 695   BufferedStackTrace *ptrace =
 696       new(internal_alloc(MBlockStackTrace, sizeof(BufferedStackTrace)))
 697           BufferedStackTrace();
 698   ptrace->Unwind(kStackTraceMax, pc, 0, 0, 0, 0, false);
 699   for (uptr i = 0; i < ptrace->size / 2; i++) {
 700     uptr tmp = ptrace->trace_buffer[i];
 701     ptrace->trace_buffer[i] = ptrace->trace_buffer[ptrace->size - i - 1];
 702     ptrace->trace_buffer[ptrace->size - i - 1] = tmp;
 703   }
 704   PrintStack(SymbolizeStack(*ptrace));
 705 #endif
 706 }
 707
 708 }  // namespace __tsan
 709
 710 using namespace __tsan;
 711
 712 extern "C" {
 713 SANITIZER_INTERFACE_ATTRIBUTE
 714 void __sanitizer_print_stack_trace() {
 715   PrintCurrentStackSlow(StackTrace::GetCurrentPc());
 716 }
 717 }  // extern "C"