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, uptr tag) {
 145   ctx->thread_registry->CheckLocked();
 146   void *mem = internal_alloc(MBlockReport, sizeof(ReportDesc));
 147   rep_ = new(mem) ReportDesc;
 148   rep_->typ = typ;
 149   rep_->tag = tag;
 150   ctx->report_mtx.Lock();
 151   CommonSanitizerReportMutex.Lock();
 152 }
 153
 154 ScopedReport::~ScopedReport() {
 155   CommonSanitizerReportMutex.Unlock();
 156   ctx->report_mtx.Unlock();
 157   DestroyAndFree(rep_);
 158 }
 159
 160 void ScopedReport::AddStack(StackTrace stack, bool suppressable) {
 161   ReportStack **rs = rep_->stacks.PushBack();
 162   *rs = SymbolizeStack(stack);
 163   (*rs)->suppressable = suppressable;
 164 }
 165
 166 void ScopedReport::AddMemoryAccess(uptr addr, uptr external_tag, Shadow s,
 167                                    StackTrace stack, const MutexSet *mset) {
 168   void *mem = internal_alloc(MBlockReportMop, sizeof(ReportMop));
 169   ReportMop *mop = new(mem) ReportMop;
 170   rep_->mops.PushBack(mop);
 171   mop->tid = s.tid();
 172   mop->addr = addr + s.addr0();
 173   mop->size = s.size();
 174   mop->write = s.IsWrite();
 175   mop->atomic = s.IsAtomic();
 176   mop->stack = SymbolizeStack(stack);
 177   mop->external_tag = external_tag;
 178   if (mop->stack)
 179     mop->stack->suppressable = true;
 180   for (uptr i = 0; i < mset->Size(); i++) {
 181     MutexSet::Desc d = mset->Get(i);
 182     u64 mid = this->AddMutex(d.id);
 183     ReportMopMutex mtx = {mid, d.write};
 184     mop->mset.PushBack(mtx);
 185   }
 186 }
 187
 188 void ScopedReport::AddUniqueTid(int unique_tid) {
 189   rep_->unique_tids.PushBack(unique_tid);
 190 }
 191
 192 void ScopedReport::AddThread(const ThreadContext *tctx, bool suppressable) {
 193   for (uptr i = 0; i < rep_->threads.Size(); i++) {
 194     if ((u32)rep_->threads[i]->id == tctx->tid)
 195       return;
 196   }
 197   void *mem = internal_alloc(MBlockReportThread, sizeof(ReportThread));
 198   ReportThread *rt = new(mem) ReportThread;
 199   rep_->threads.PushBack(rt);
 200   rt->id = tctx->tid;
 201   rt->os_id = tctx->os_id;
 202   rt->running = (tctx->status == ThreadStatusRunning);
 203   rt->name = internal_strdup(tctx->name);
 204   rt->parent_tid = tctx->parent_tid;
 205   rt->workerthread = tctx->workerthread;
 206   rt->stack = 0;
 207   rt->stack = SymbolizeStackId(tctx->creation_stack_id);
 208   if (rt->stack)
 209     rt->stack->suppressable = suppressable;
 210 }
 211
 212 #if !SANITIZER_GO
 213 static bool FindThreadByUidLockedCallback(ThreadContextBase *tctx, void *arg) {
 214   int unique_id = *(int *)arg;
 215   return tctx->unique_id == (u32)unique_id;
 216 }
 217
 218 static ThreadContext *FindThreadByUidLocked(int unique_id) {
 219   ctx->thread_registry->CheckLocked();
 220   return static_cast<ThreadContext *>(
 221       ctx->thread_registry->FindThreadContextLocked(
 222           FindThreadByUidLockedCallback, &unique_id));
 223 }
 224
 225 static ThreadContext *FindThreadByTidLocked(int tid) {
 226   ctx->thread_registry->CheckLocked();
 227   return static_cast<ThreadContext*>(
 228       ctx->thread_registry->GetThreadLocked(tid));
 229 }
 230
 231 static bool IsInStackOrTls(ThreadContextBase *tctx_base, void *arg) {
 232   uptr addr = (uptr)arg;
 233   ThreadContext *tctx = static_cast<ThreadContext*>(tctx_base);
 234   if (tctx->status != ThreadStatusRunning)
 235     return false;
 236   ThreadState *thr = tctx->thr;
 237   CHECK(thr);
 238   return ((addr >= thr->stk_addr && addr < thr->stk_addr + thr->stk_size) ||
 239           (addr >= thr->tls_addr && addr < thr->tls_addr + thr->tls_size));
 240 }
 241
 242 ThreadContext *IsThreadStackOrTls(uptr addr, bool *is_stack) {
 243   ctx->thread_registry->CheckLocked();
 244   ThreadContext *tctx = static_cast<ThreadContext*>(
 245       ctx->thread_registry->FindThreadContextLocked(IsInStackOrTls,
 246                                                     (void*)addr));
 247   if (!tctx)
 248     return 0;
 249   ThreadState *thr = tctx->thr;
 250   CHECK(thr);
 251   *is_stack = (addr >= thr->stk_addr && addr < thr->stk_addr + thr->stk_size);
 252   return tctx;
 253 }
 254 #endif
 255
 256 void ScopedReport::AddThread(int unique_tid, bool suppressable) {
 257 #if !SANITIZER_GO
 258   if (const ThreadContext *tctx = FindThreadByUidLocked(unique_tid))
 259     AddThread(tctx, suppressable);
 260 #endif
 261 }
 262
 263 void ScopedReport::AddMutex(const SyncVar *s) {
 264   for (uptr i = 0; i < rep_->mutexes.Size(); i++) {
 265     if (rep_->mutexes[i]->id == s->uid)
 266       return;
 267   }
 268   void *mem = internal_alloc(MBlockReportMutex, sizeof(ReportMutex));
 269   ReportMutex *rm = new(mem) ReportMutex;
 270   rep_->mutexes.PushBack(rm);
 271   rm->id = s->uid;
 272   rm->addr = s->addr;
 273   rm->destroyed = false;
 274   rm->stack = SymbolizeStackId(s->creation_stack_id);
 275 }
 276
 277 u64 ScopedReport::AddMutex(u64 id) {
 278   u64 uid = 0;
 279   u64 mid = id;
 280   uptr addr = SyncVar::SplitId(id, &uid);
 281   SyncVar *s = ctx->metamap.GetIfExistsAndLock(addr, true);
 282   // Check that the mutex is still alive.
 283   // Another mutex can be created at the same address,
 284   // so check uid as well.
 285   if (s && s->CheckId(uid)) {
 286     mid = s->uid;
 287     AddMutex(s);
 288   } else {
 289     AddDeadMutex(id);
 290   }
 291   if (s)
 292     s->mtx.Unlock();
 293   return mid;
 294 }
 295
 296 void ScopedReport::AddDeadMutex(u64 id) {
 297   for (uptr i = 0; i < rep_->mutexes.Size(); i++) {
 298     if (rep_->mutexes[i]->id == id)
 299       return;
 300   }
 301   void *mem = internal_alloc(MBlockReportMutex, sizeof(ReportMutex));
 302   ReportMutex *rm = new(mem) ReportMutex;
 303   rep_->mutexes.PushBack(rm);
 304   rm->id = id;
 305   rm->addr = 0;
 306   rm->destroyed = true;
 307   rm->stack = 0;
 308 }
 309
 310 void ScopedReport::AddLocation(uptr addr, uptr size) {
 311   if (addr == 0)
 312     return;
 313 #if !SANITIZER_GO
 314   int fd = -1;
 315   int creat_tid = kInvalidTid;
 316   u32 creat_stack = 0;
 317   if (FdLocation(addr, &fd, &creat_tid, &creat_stack)) {
 318     ReportLocation *loc = ReportLocation::New(ReportLocationFD);
 319     loc->fd = fd;
 320     loc->tid = creat_tid;
 321     loc->stack = SymbolizeStackId(creat_stack);
 322     rep_->locs.PushBack(loc);
 323     ThreadContext *tctx = FindThreadByUidLocked(creat_tid);
 324     if (tctx)
 325       AddThread(tctx);
 326     return;
 327   }
 328   MBlock *b = 0;
 329   Allocator *a = allocator();
 330   if (a->PointerIsMine((void*)addr)) {
 331     void *block_begin = a->GetBlockBegin((void*)addr);
 332     if (block_begin)
 333       b = ctx->metamap.GetBlock((uptr)block_begin);
 334   }
 335   if (b != 0) {
 336     ThreadContext *tctx = FindThreadByTidLocked(b->tid);
 337     ReportLocation *loc = ReportLocation::New(ReportLocationHeap);
 338     loc->heap_chunk_start = (uptr)allocator()->GetBlockBegin((void *)addr);
 339     loc->heap_chunk_size = b->siz;
 340     loc->external_tag = b->tag;
 341     loc->tid = tctx ? tctx->tid : b->tid;
 342     loc->stack = SymbolizeStackId(b->stk);
 343     rep_->locs.PushBack(loc);
 344     if (tctx)
 345       AddThread(tctx);
 346     return;
 347   }
 348   bool is_stack = false;
 349   if (ThreadContext *tctx = IsThreadStackOrTls(addr, &is_stack)) {
 350     ReportLocation *loc =
 351         ReportLocation::New(is_stack ? ReportLocationStack : ReportLocationTLS);
 352     loc->tid = tctx->tid;
 353     rep_->locs.PushBack(loc);
 354     AddThread(tctx);
 355   }
 356 #endif
 357   if (ReportLocation *loc = SymbolizeData(addr)) {
 358     loc->suppressable = true;
 359     rep_->locs.PushBack(loc);
 360     return;
 361   }
 362 }
 363
 364 #if !SANITIZER_GO
 365 void ScopedReport::AddSleep(u32 stack_id) {
 366   rep_->sleep = SymbolizeStackId(stack_id);
 367 }
 368 #endif
 369
 370 void ScopedReport::SetCount(int count) {
 371   rep_->count = count;
 372 }
 373
 374 const ReportDesc *ScopedReport::GetReport() const {
 375   return rep_;
 376 }
 377
 378 void RestoreStack(int tid, const u64 epoch, VarSizeStackTrace *stk,
 379                   MutexSet *mset, uptr *tag) {
 380   // This function restores stack trace and mutex set for the thread/epoch.
 381   // It does so by getting stack trace and mutex set at the beginning of
 382   // trace part, and then replaying the trace till the given epoch.
 383   Trace* trace = ThreadTrace(tid);
 384   ReadLock l(&trace->mtx);
 385   const int partidx = (epoch / kTracePartSize) % TraceParts();
 386   TraceHeader* hdr = &trace->headers[partidx];
 387   if (epoch < hdr->epoch0 || epoch >= hdr->epoch0 + kTracePartSize)
 388     return;
 389   CHECK_EQ(RoundDown(epoch, kTracePartSize), hdr->epoch0);
 390   const u64 epoch0 = RoundDown(epoch, TraceSize());
 391   const u64 eend = epoch % TraceSize();
 392   const u64 ebegin = RoundDown(eend, kTracePartSize);
 393   DPrintf("#%d: RestoreStack epoch=%zu ebegin=%zu eend=%zu partidx=%d\n",
 394           tid, (uptr)epoch, (uptr)ebegin, (uptr)eend, partidx);
 395   Vector<uptr> stack(MBlockReportStack);
 396   stack.Resize(hdr->stack0.size + 64);
 397   for (uptr i = 0; i < hdr->stack0.size; i++) {
 398     stack[i] = hdr->stack0.trace[i];
 399     DPrintf2("  #%02zu: pc=%zx\n", i, stack[i]);
 400   }
 401   if (mset)
 402     *mset = hdr->mset0;
 403   uptr pos = hdr->stack0.size;
 404   Event *events = (Event*)GetThreadTrace(tid);
 405   for (uptr i = ebegin; i <= eend; i++) {
 406     Event ev = events[i];
 407     EventType typ = (EventType)(ev >> kEventPCBits);
 408     uptr pc = (uptr)(ev & ((1ull << kEventPCBits) - 1));
 409     DPrintf2("  %zu typ=%d pc=%zx\n", i, typ, pc);
 410     if (typ == EventTypeMop) {
 411       stack[pos] = pc;
 412     } else if (typ == EventTypeFuncEnter) {
 413       if (stack.Size() < pos + 2)
 414         stack.Resize(pos + 2);
 415       stack[pos++] = pc;
 416     } else if (typ == EventTypeFuncExit) {
 417       if (pos > 0)
 418         pos--;
 419     }
 420     if (mset) {
 421       if (typ == EventTypeLock) {
 422         mset->Add(pc, true, epoch0 + i);
 423       } else if (typ == EventTypeUnlock) {
 424         mset->Del(pc, true);
 425       } else if (typ == EventTypeRLock) {
 426         mset->Add(pc, false, epoch0 + i);
 427       } else if (typ == EventTypeRUnlock) {
 428         mset->Del(pc, false);
 429       }
 430     }
 431     for (uptr j = 0; j <= pos; j++)
 432       DPrintf2("      #%zu: %zx\n", j, stack[j]);
 433   }
 434   if (pos == 0 && stack[0] == 0)
 435     return;
 436   pos++;
 437   stk->Init(&stack[0], pos);
 438   ExtractTagFromStack(stk, tag);
 439 }
 440
 441 static bool HandleRacyStacks(ThreadState *thr, VarSizeStackTrace traces[2],
 442                              uptr addr_min, uptr addr_max) {
 443   bool equal_stack = false;
 444   RacyStacks hash;
 445   bool equal_address = false;
 446   RacyAddress ra0 = {addr_min, addr_max};
 447   {
 448     ReadLock lock(&ctx->racy_mtx);
 449     if (flags()->suppress_equal_stacks) {
 450       hash.hash[0] = md5_hash(traces[0].trace, traces[0].size * sizeof(uptr));
 451       hash.hash[1] = md5_hash(traces[1].trace, traces[1].size * sizeof(uptr));
 452       for (uptr i = 0; i < ctx->racy_stacks.Size(); i++) {
 453         if (hash == ctx->racy_stacks[i]) {
 454           VPrintf(2,
 455               "ThreadSanitizer: suppressing report as doubled (stack)\n");
 456           equal_stack = true;
 457           break;
 458         }
 459       }
 460     }
 461     if (flags()->suppress_equal_addresses) {
 462       for (uptr i = 0; i < ctx->racy_addresses.Size(); i++) {
 463         RacyAddress ra2 = ctx->racy_addresses[i];
 464         uptr maxbeg = max(ra0.addr_min, ra2.addr_min);
 465         uptr minend = min(ra0.addr_max, ra2.addr_max);
 466         if (maxbeg < minend) {
 467           VPrintf(2, "ThreadSanitizer: suppressing report as doubled (addr)\n");
 468           equal_address = true;
 469           break;
 470         }
 471       }
 472     }
 473   }
 474   if (!equal_stack && !equal_address)
 475     return false;
 476   if (!equal_stack) {
 477     Lock lock(&ctx->racy_mtx);
 478     ctx->racy_stacks.PushBack(hash);
 479   }
 480   if (!equal_address) {
 481     Lock lock(&ctx->racy_mtx);
 482     ctx->racy_addresses.PushBack(ra0);
 483   }
 484   return true;
 485 }
 486
 487 static void AddRacyStacks(ThreadState *thr, VarSizeStackTrace traces[2],
 488                           uptr addr_min, uptr addr_max) {
 489   Lock lock(&ctx->racy_mtx);
 490   if (flags()->suppress_equal_stacks) {
 491     RacyStacks hash;
 492     hash.hash[0] = md5_hash(traces[0].trace, traces[0].size * sizeof(uptr));
 493     hash.hash[1] = md5_hash(traces[1].trace, traces[1].size * sizeof(uptr));
 494     ctx->racy_stacks.PushBack(hash);
 495   }
 496   if (flags()->suppress_equal_addresses) {
 497     RacyAddress ra0 = {addr_min, addr_max};
 498     ctx->racy_addresses.PushBack(ra0);
 499   }
 500 }
 501
 502 bool OutputReport(ThreadState *thr, const ScopedReport &srep) {
 503   if (!flags()->report_bugs || thr->suppress_reports)
 504     return false;
 505   atomic_store_relaxed(&ctx->last_symbolize_time_ns, NanoTime());
 506   const ReportDesc *rep = srep.GetReport();
 507   CHECK_EQ(thr->current_report, nullptr);
 508   thr->current_report = rep;
 509   Suppression *supp = 0;
 510   uptr pc_or_addr = 0;
 511   for (uptr i = 0; pc_or_addr == 0 && i < rep->mops.Size(); i++)
 512     pc_or_addr = IsSuppressed(rep->typ, rep->mops[i]->stack, &supp);
 513   for (uptr i = 0; pc_or_addr == 0 && i < rep->stacks.Size(); i++)
 514     pc_or_addr = IsSuppressed(rep->typ, rep->stacks[i], &supp);
 515   for (uptr i = 0; pc_or_addr == 0 && i < rep->threads.Size(); i++)
 516     pc_or_addr = IsSuppressed(rep->typ, rep->threads[i]->stack, &supp);
 517   for (uptr i = 0; pc_or_addr == 0 && i < rep->locs.Size(); i++)
 518     pc_or_addr = IsSuppressed(rep->typ, rep->locs[i], &supp);
 519   if (pc_or_addr != 0) {
 520     Lock lock(&ctx->fired_suppressions_mtx);
 521     FiredSuppression s = {srep.GetReport()->typ, pc_or_addr, supp};
 522     ctx->fired_suppressions.push_back(s);
 523   }
 524   {
 525     bool old_is_freeing = thr->is_freeing;
 526     thr->is_freeing = false;
 527     bool suppressed = OnReport(rep, pc_or_addr != 0);
 528     thr->is_freeing = old_is_freeing;
 529     if (suppressed) {
 530       thr->current_report = nullptr;
 531       return false;
 532     }
 533   }
 534   PrintReport(rep);
 535   __tsan_on_report(rep);
 536   ctx->nreported++;
 537   if (flags()->halt_on_error)
 538     Die();
 539   thr->current_report = nullptr;
 540   return true;
 541 }
 542
 543 bool IsFiredSuppression(Context *ctx, ReportType type, StackTrace trace) {
 544   ReadLock lock(&ctx->fired_suppressions_mtx);
 545   for (uptr k = 0; k < ctx->fired_suppressions.size(); k++) {
 546     if (ctx->fired_suppressions[k].type != type)
 547       continue;
 548     for (uptr j = 0; j < trace.size; j++) {
 549       FiredSuppression *s = &ctx->fired_suppressions[k];
 550       if (trace.trace[j] == s->pc_or_addr) {
 551         if (s->supp)
 552           atomic_fetch_add(&s->supp->hit_count, 1, memory_order_relaxed);
 553         return true;
 554       }
 555     }
 556   }
 557   return false;
 558 }
 559
 560 static bool IsFiredSuppression(Context *ctx, ReportType type, uptr addr) {
 561   ReadLock lock(&ctx->fired_suppressions_mtx);
 562   for (uptr k = 0; k < ctx->fired_suppressions.size(); k++) {
 563     if (ctx->fired_suppressions[k].type != type)
 564       continue;
 565     FiredSuppression *s = &ctx->fired_suppressions[k];
 566     if (addr == s->pc_or_addr) {
 567       if (s->supp)
 568         atomic_fetch_add(&s->supp->hit_count, 1, memory_order_relaxed);
 569       return true;
 570     }
 571   }
 572   return false;
 573 }
 574
 575 static bool RaceBetweenAtomicAndFree(ThreadState *thr) {
 576   Shadow s0(thr->racy_state[0]);
 577   Shadow s1(thr->racy_state[1]);
 578   CHECK(!(s0.IsAtomic() && s1.IsAtomic()));
 579   if (!s0.IsAtomic() && !s1.IsAtomic())
 580     return true;
 581   if (s0.IsAtomic() && s1.IsFreed())
 582     return true;
 583   if (s1.IsAtomic() && thr->is_freeing)
 584     return true;
 585   return false;
 586 }
 587
 588 void ReportRace(ThreadState *thr) {
 589   CheckNoLocks(thr);
 590
 591   // Symbolizer makes lots of intercepted calls. If we try to process them,
 592   // at best it will cause deadlocks on internal mutexes.
 593   ScopedIgnoreInterceptors ignore;
 594
 595   if (!flags()->report_bugs)
 596     return;
 597   if (!flags()->report_atomic_races && !RaceBetweenAtomicAndFree(thr))
 598     return;
 599
 600   bool freed = false;
 601   {
 602     Shadow s(thr->racy_state[1]);
 603     freed = s.GetFreedAndReset();
 604     thr->racy_state[1] = s.raw();
 605   }
 606
 607   uptr addr = ShadowToMem((uptr)thr->racy_shadow_addr);
 608   uptr addr_min = 0;
 609   uptr addr_max = 0;
 610   {
 611     uptr a0 = addr + Shadow(thr->racy_state[0]).addr0();
 612     uptr a1 = addr + Shadow(thr->racy_state[1]).addr0();
 613     uptr e0 = a0 + Shadow(thr->racy_state[0]).size();
 614     uptr e1 = a1 + Shadow(thr->racy_state[1]).size();
 615     addr_min = min(a0, a1);
 616     addr_max = max(e0, e1);
 617     if (IsExpectedReport(addr_min, addr_max - addr_min))
 618       return;
 619   }
 620
 621   ReportType typ = ReportTypeRace;
 622   if (thr->is_vptr_access && freed)
 623     typ = ReportTypeVptrUseAfterFree;
 624   else if (thr->is_vptr_access)
 625     typ = ReportTypeVptrRace;
 626   else if (freed)
 627     typ = ReportTypeUseAfterFree;
 628
 629   if (IsFiredSuppression(ctx, typ, addr))
 630     return;
 631
 632   const uptr kMop = 2;
 633   VarSizeStackTrace traces[kMop];
 634   uptr tags[kMop] = {kExternalTagNone};
 635   uptr toppc = TraceTopPC(thr);
 636   if (toppc >> kEventPCBits) {
 637     // This is a work-around for a known issue.
 638     // The scenario where this happens is rather elaborate and requires
 639     // an instrumented __sanitizer_report_error_summary callback and
 640     // a __tsan_symbolize_external callback and a race during a range memory
 641     // access larger than 8 bytes. MemoryAccessRange adds the current PC to
 642     // the trace and starts processing memory accesses. A first memory access
 643     // triggers a race, we report it and call the instrumented
 644     // __sanitizer_report_error_summary, which adds more stuff to the trace
 645     // since it is intrumented. Then a second memory access in MemoryAccessRange
 646     // also triggers a race and we get here and call TraceTopPC to get the
 647     // current PC, however now it contains some unrelated events from the
 648     // callback. Most likely, TraceTopPC will now return a EventTypeFuncExit
 649     // event. Later we subtract -1 from it (in GetPreviousInstructionPc)
 650     // and the resulting PC has kExternalPCBit set, so we pass it to
 651     // __tsan_symbolize_external. __tsan_symbolize_external is within its rights
 652     // to crash since the PC is completely bogus.
 653     // test/tsan/double_race.cc contains a test case for this.
 654     toppc = 0;
 655   }
 656   ObtainCurrentStack(thr, toppc, &traces[0], &tags[0]);
 657   if (IsFiredSuppression(ctx, typ, traces[0]))
 658     return;
 659
 660   // MutexSet is too large to live on stack.
 661   Vector<u64> mset_buffer(MBlockScopedBuf);
 662   mset_buffer.Resize(sizeof(MutexSet) / sizeof(u64) + 1);
 663   MutexSet *mset2 = new(&mset_buffer[0]) MutexSet();
 664
 665   Shadow s2(thr->racy_state[1]);
 666   RestoreStack(s2.tid(), s2.epoch(), &traces[1], mset2, &tags[1]);
 667   if (IsFiredSuppression(ctx, typ, traces[1]))
 668     return;
 669
 670   if (HandleRacyStacks(thr, traces, addr_min, addr_max))
 671     return;
 672
 673   // If any of the accesses has a tag, treat this as an "external" race.
 674   uptr tag = kExternalTagNone;
 675   for (uptr i = 0; i < kMop; i++) {
 676     if (tags[i] != kExternalTagNone) {
 677       typ = ReportTypeExternalRace;
 678       tag = tags[i];
 679       break;
 680     }
 681   }
 682
 683   ThreadRegistryLock l0(ctx->thread_registry);
 684   ScopedReport rep(typ, tag);
 685   for (uptr i = 0; i < kMop; i++) {
 686     Shadow s(thr->racy_state[i]);
 687     rep.AddMemoryAccess(addr, tags[i], s, traces[i],
 688                         i == 0 ? &thr->mset : mset2);
 689   }
 690
 691   for (uptr i = 0; i < kMop; i++) {
 692     FastState s(thr->racy_state[i]);
 693     ThreadContext *tctx = static_cast<ThreadContext*>(
 694         ctx->thread_registry->GetThreadLocked(s.tid()));
 695     if (s.epoch() < tctx->epoch0 || s.epoch() > tctx->epoch1)
 696       continue;
 697     rep.AddThread(tctx);
 698   }
 699
 700   rep.AddLocation(addr_min, addr_max - addr_min);
 701
 702 #if !SANITIZER_GO
 703   {  // NOLINT
 704     Shadow s(thr->racy_state[1]);
 705     if (s.epoch() <= thr->last_sleep_clock.get(s.tid()))
 706       rep.AddSleep(thr->last_sleep_stack_id);
 707   }
 708 #endif
 709
 710   if (!OutputReport(thr, rep))
 711     return;
 712
 713   AddRacyStacks(thr, traces, addr_min, addr_max);
 714 }
 715
 716 void PrintCurrentStack(ThreadState *thr, uptr pc) {
 717   VarSizeStackTrace trace;
 718   ObtainCurrentStack(thr, pc, &trace);
 719   PrintStack(SymbolizeStack(trace));
 720 }
 721
 722 // Always inlining PrintCurrentStackSlow, because LocatePcInTrace assumes
 723 // __sanitizer_print_stack_trace exists in the actual unwinded stack, but
 724 // tail-call to PrintCurrentStackSlow breaks this assumption because
 725 // __sanitizer_print_stack_trace disappears after tail-call.
 726 // However, this solution is not reliable enough, please see dvyukov's comment
 727 // http://reviews.llvm.org/D19148#406208
 728 // Also see PR27280 comment 2 and 3 for breaking examples and analysis.
 729 ALWAYS_INLINE
 730 void PrintCurrentStackSlow(uptr pc) {
 731 #if !SANITIZER_GO
 732   BufferedStackTrace *ptrace =
 733       new(internal_alloc(MBlockStackTrace, sizeof(BufferedStackTrace)))
 734           BufferedStackTrace();
 735   ptrace->Unwind(kStackTraceMax, pc, 0, 0, 0, 0, false);
 736   for (uptr i = 0; i < ptrace->size / 2; i++) {
 737     uptr tmp = ptrace->trace_buffer[i];
 738     ptrace->trace_buffer[i] = ptrace->trace_buffer[ptrace->size - i - 1];
 739     ptrace->trace_buffer[ptrace->size - i - 1] = tmp;
 740   }
 741   PrintStack(SymbolizeStack(*ptrace));
 742 #endif
 743 }
 744
 745 }  // namespace __tsan
 746
 747 using namespace __tsan;
 748
 749 extern "C" {
 750 SANITIZER_INTERFACE_ATTRIBUTE
 751 void __sanitizer_print_stack_trace() {
 752   PrintCurrentStackSlow(StackTrace::GetCurrentPc());
 753 }
 754 }  // extern "C"