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1 //===-- tsan_rtl_report.cc ------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file is a part of ThreadSanitizer (TSan), a race detector.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "sanitizer_common/sanitizer_libc.h"
15 #include "sanitizer_common/sanitizer_placement_new.h"
16 #include "sanitizer_common/sanitizer_stackdepot.h"
17 #include "sanitizer_common/sanitizer_common.h"
18 #include "sanitizer_common/sanitizer_stacktrace.h"
19 #include "tsan_platform.h"
20 #include "tsan_rtl.h"
21 #include "tsan_suppressions.h"
22 #include "tsan_symbolize.h"
23 #include "tsan_report.h"
24 #include "tsan_sync.h"
25 #include "tsan_mman.h"
26 #include "tsan_flags.h"
27 #include "tsan_fd.h"
28 
29 namespace __tsan {
30 
31 using namespace __sanitizer;  // NOLINT
32 
33 static ReportStack *SymbolizeStack(StackTrace trace);
34 
TsanCheckFailed(const char * file,int line,const char * cond,u64 v1,u64 v2)35 void TsanCheckFailed(const char *file, int line, const char *cond,
36                      u64 v1, u64 v2) {
37   // There is high probability that interceptors will check-fail as well,
38   // on the other hand there is no sense in processing interceptors
39   // since we are going to die soon.
40   ScopedIgnoreInterceptors ignore;
41   Printf("FATAL: ThreadSanitizer CHECK failed: "
42          "%s:%d \"%s\" (0x%zx, 0x%zx)\n",
43          file, line, cond, (uptr)v1, (uptr)v2);
44   PrintCurrentStackSlow(StackTrace::GetCurrentPc());
45   Die();
46 }
47 
48 // Can be overriden by an application/test to intercept reports.
49 #ifdef TSAN_EXTERNAL_HOOKS
50 bool OnReport(const ReportDesc *rep, bool suppressed);
51 #else
52 SANITIZER_WEAK_CXX_DEFAULT_IMPL
OnReport(const ReportDesc * rep,bool suppressed)53 bool OnReport(const ReportDesc *rep, bool suppressed) {
54   (void)rep;
55   return suppressed;
56 }
57 #endif
58 
StackStripMain(SymbolizedStack * frames)59 static void StackStripMain(SymbolizedStack *frames) {
60   SymbolizedStack *last_frame = nullptr;
61   SymbolizedStack *last_frame2 = nullptr;
62   for (SymbolizedStack *cur = frames; cur; cur = cur->next) {
63     last_frame2 = last_frame;
64     last_frame = cur;
65   }
66 
67   if (last_frame2 == 0)
68     return;
69 #ifndef SANITIZER_GO
70   const char *last = last_frame->info.function;
71   const char *last2 = last_frame2->info.function;
72   // Strip frame above 'main'
73   if (last2 && 0 == internal_strcmp(last2, "main")) {
74     last_frame->ClearAll();
75     last_frame2->next = nullptr;
76   // Strip our internal thread start routine.
77   } else if (last && 0 == internal_strcmp(last, "__tsan_thread_start_func")) {
78     last_frame->ClearAll();
79     last_frame2->next = nullptr;
80   // Strip global ctors init.
81   } else if (last && 0 == internal_strcmp(last, "__do_global_ctors_aux")) {
82     last_frame->ClearAll();
83     last_frame2->next = nullptr;
84   // If both are 0, then we probably just failed to symbolize.
85   } else if (last || last2) {
86     // Ensure that we recovered stack completely. Trimmed stack
87     // can actually happen if we do not instrument some code,
88     // so it's only a debug print. However we must try hard to not miss it
89     // due to our fault.
90     DPrintf("Bottom stack frame is missed\n");
91   }
92 #else
93   // The last frame always point into runtime (gosched0, goexit0, runtime.main).
94   last_frame->ClearAll();
95   last_frame2->next = nullptr;
96 #endif
97 }
98 
SymbolizeStackId(u32 stack_id)99 ReportStack *SymbolizeStackId(u32 stack_id) {
100   if (stack_id == 0)
101     return 0;
102   StackTrace stack = StackDepotGet(stack_id);
103   if (stack.trace == nullptr)
104     return nullptr;
105   return SymbolizeStack(stack);
106 }
107 
SymbolizeStack(StackTrace trace)108 static ReportStack *SymbolizeStack(StackTrace trace) {
109   if (trace.size == 0)
110     return 0;
111   SymbolizedStack *top = nullptr;
112   for (uptr si = 0; si < trace.size; si++) {
113     const uptr pc = trace.trace[si];
114     uptr pc1 = pc;
115     // We obtain the return address, but we're interested in the previous
116     // instruction.
117     if ((pc & kExternalPCBit) == 0)
118       pc1 = StackTrace::GetPreviousInstructionPc(pc);
119     SymbolizedStack *ent = SymbolizeCode(pc1);
120     CHECK_NE(ent, 0);
121     SymbolizedStack *last = ent;
122     while (last->next) {
123       last->info.address = pc;  // restore original pc for report
124       last = last->next;
125     }
126     last->info.address = pc;  // restore original pc for report
127     last->next = top;
128     top = ent;
129   }
130   StackStripMain(top);
131 
132   ReportStack *stack = ReportStack::New();
133   stack->frames = top;
134   return stack;
135 }
136 
ScopedReport(ReportType typ)137 ScopedReport::ScopedReport(ReportType typ) {
138   ctx->thread_registry->CheckLocked();
139   void *mem = internal_alloc(MBlockReport, sizeof(ReportDesc));
140   rep_ = new(mem) ReportDesc;
141   rep_->typ = typ;
142   ctx->report_mtx.Lock();
143   CommonSanitizerReportMutex.Lock();
144 }
145 
~ScopedReport()146 ScopedReport::~ScopedReport() {
147   CommonSanitizerReportMutex.Unlock();
148   ctx->report_mtx.Unlock();
149   DestroyAndFree(rep_);
150 }
151 
AddStack(StackTrace stack,bool suppressable)152 void ScopedReport::AddStack(StackTrace stack, bool suppressable) {
153   ReportStack **rs = rep_->stacks.PushBack();
154   *rs = SymbolizeStack(stack);
155   (*rs)->suppressable = suppressable;
156 }
157 
AddMemoryAccess(uptr addr,Shadow s,StackTrace stack,const MutexSet * mset)158 void ScopedReport::AddMemoryAccess(uptr addr, Shadow s, StackTrace stack,
159                                    const MutexSet *mset) {
160   void *mem = internal_alloc(MBlockReportMop, sizeof(ReportMop));
161   ReportMop *mop = new(mem) ReportMop;
162   rep_->mops.PushBack(mop);
163   mop->tid = s.tid();
164   mop->addr = addr + s.addr0();
165   mop->size = s.size();
166   mop->write = s.IsWrite();
167   mop->atomic = s.IsAtomic();
168   mop->stack = SymbolizeStack(stack);
169   if (mop->stack)
170     mop->stack->suppressable = true;
171   for (uptr i = 0; i < mset->Size(); i++) {
172     MutexSet::Desc d = mset->Get(i);
173     u64 mid = this->AddMutex(d.id);
174     ReportMopMutex mtx = {mid, d.write};
175     mop->mset.PushBack(mtx);
176   }
177 }
178 
AddUniqueTid(int unique_tid)179 void ScopedReport::AddUniqueTid(int unique_tid) {
180   rep_->unique_tids.PushBack(unique_tid);
181 }
182 
AddThread(const ThreadContext * tctx,bool suppressable)183 void ScopedReport::AddThread(const ThreadContext *tctx, bool suppressable) {
184   for (uptr i = 0; i < rep_->threads.Size(); i++) {
185     if ((u32)rep_->threads[i]->id == tctx->tid)
186       return;
187   }
188   void *mem = internal_alloc(MBlockReportThread, sizeof(ReportThread));
189   ReportThread *rt = new(mem) ReportThread;
190   rep_->threads.PushBack(rt);
191   rt->id = tctx->tid;
192   rt->pid = tctx->os_id;
193   rt->running = (tctx->status == ThreadStatusRunning);
194   rt->name = internal_strdup(tctx->name);
195   rt->parent_tid = tctx->parent_tid;
196   rt->stack = 0;
197   rt->stack = SymbolizeStackId(tctx->creation_stack_id);
198   if (rt->stack)
199     rt->stack->suppressable = suppressable;
200 }
201 
202 #ifndef SANITIZER_GO
FindThreadByUidLockedCallback(ThreadContextBase * tctx,void * arg)203 static bool FindThreadByUidLockedCallback(ThreadContextBase *tctx, void *arg) {
204   int unique_id = *(int *)arg;
205   return tctx->unique_id == (u32)unique_id;
206 }
207 
FindThreadByUidLocked(int unique_id)208 static ThreadContext *FindThreadByUidLocked(int unique_id) {
209   ctx->thread_registry->CheckLocked();
210   return static_cast<ThreadContext *>(
211       ctx->thread_registry->FindThreadContextLocked(
212           FindThreadByUidLockedCallback, &unique_id));
213 }
214 
FindThreadByTidLocked(int tid)215 static ThreadContext *FindThreadByTidLocked(int tid) {
216   ctx->thread_registry->CheckLocked();
217   return static_cast<ThreadContext*>(
218       ctx->thread_registry->GetThreadLocked(tid));
219 }
220 
IsInStackOrTls(ThreadContextBase * tctx_base,void * arg)221 static bool IsInStackOrTls(ThreadContextBase *tctx_base, void *arg) {
222   uptr addr = (uptr)arg;
223   ThreadContext *tctx = static_cast<ThreadContext*>(tctx_base);
224   if (tctx->status != ThreadStatusRunning)
225     return false;
226   ThreadState *thr = tctx->thr;
227   CHECK(thr);
228   return ((addr >= thr->stk_addr && addr < thr->stk_addr + thr->stk_size) ||
229           (addr >= thr->tls_addr && addr < thr->tls_addr + thr->tls_size));
230 }
231 
IsThreadStackOrTls(uptr addr,bool * is_stack)232 ThreadContext *IsThreadStackOrTls(uptr addr, bool *is_stack) {
233   ctx->thread_registry->CheckLocked();
234   ThreadContext *tctx = static_cast<ThreadContext*>(
235       ctx->thread_registry->FindThreadContextLocked(IsInStackOrTls,
236                                                     (void*)addr));
237   if (!tctx)
238     return 0;
239   ThreadState *thr = tctx->thr;
240   CHECK(thr);
241   *is_stack = (addr >= thr->stk_addr && addr < thr->stk_addr + thr->stk_size);
242   return tctx;
243 }
244 #endif
245 
AddThread(int unique_tid,bool suppressable)246 void ScopedReport::AddThread(int unique_tid, bool suppressable) {
247 #ifndef SANITIZER_GO
248   if (const ThreadContext *tctx = FindThreadByUidLocked(unique_tid))
249     AddThread(tctx, suppressable);
250 #endif
251 }
252 
AddMutex(const SyncVar * s)253 void ScopedReport::AddMutex(const SyncVar *s) {
254   for (uptr i = 0; i < rep_->mutexes.Size(); i++) {
255     if (rep_->mutexes[i]->id == s->uid)
256       return;
257   }
258   void *mem = internal_alloc(MBlockReportMutex, sizeof(ReportMutex));
259   ReportMutex *rm = new(mem) ReportMutex;
260   rep_->mutexes.PushBack(rm);
261   rm->id = s->uid;
262   rm->addr = s->addr;
263   rm->destroyed = false;
264   rm->stack = SymbolizeStackId(s->creation_stack_id);
265 }
266 
AddMutex(u64 id)267 u64 ScopedReport::AddMutex(u64 id) {
268   u64 uid = 0;
269   u64 mid = id;
270   uptr addr = SyncVar::SplitId(id, &uid);
271   SyncVar *s = ctx->metamap.GetIfExistsAndLock(addr);
272   // Check that the mutex is still alive.
273   // Another mutex can be created at the same address,
274   // so check uid as well.
275   if (s && s->CheckId(uid)) {
276     mid = s->uid;
277     AddMutex(s);
278   } else {
279     AddDeadMutex(id);
280   }
281   if (s)
282     s->mtx.Unlock();
283   return mid;
284 }
285 
AddDeadMutex(u64 id)286 void ScopedReport::AddDeadMutex(u64 id) {
287   for (uptr i = 0; i < rep_->mutexes.Size(); i++) {
288     if (rep_->mutexes[i]->id == id)
289       return;
290   }
291   void *mem = internal_alloc(MBlockReportMutex, sizeof(ReportMutex));
292   ReportMutex *rm = new(mem) ReportMutex;
293   rep_->mutexes.PushBack(rm);
294   rm->id = id;
295   rm->addr = 0;
296   rm->destroyed = true;
297   rm->stack = 0;
298 }
299 
AddLocation(uptr addr,uptr size)300 void ScopedReport::AddLocation(uptr addr, uptr size) {
301   if (addr == 0)
302     return;
303 #ifndef SANITIZER_GO
304   int fd = -1;
305   int creat_tid = -1;
306   u32 creat_stack = 0;
307   if (FdLocation(addr, &fd, &creat_tid, &creat_stack)) {
308     ReportLocation *loc = ReportLocation::New(ReportLocationFD);
309     loc->fd = fd;
310     loc->tid = creat_tid;
311     loc->stack = SymbolizeStackId(creat_stack);
312     rep_->locs.PushBack(loc);
313     ThreadContext *tctx = FindThreadByUidLocked(creat_tid);
314     if (tctx)
315       AddThread(tctx);
316     return;
317   }
318   MBlock *b = 0;
319   Allocator *a = allocator();
320   if (a->PointerIsMine((void*)addr)) {
321     void *block_begin = a->GetBlockBegin((void*)addr);
322     if (block_begin)
323       b = ctx->metamap.GetBlock((uptr)block_begin);
324   }
325   if (b != 0) {
326     ThreadContext *tctx = FindThreadByTidLocked(b->tid);
327     ReportLocation *loc = ReportLocation::New(ReportLocationHeap);
328     loc->heap_chunk_start = (uptr)allocator()->GetBlockBegin((void *)addr);
329     loc->heap_chunk_size = b->siz;
330     loc->tid = tctx ? tctx->tid : b->tid;
331     loc->stack = SymbolizeStackId(b->stk);
332     rep_->locs.PushBack(loc);
333     if (tctx)
334       AddThread(tctx);
335     return;
336   }
337   bool is_stack = false;
338   if (ThreadContext *tctx = IsThreadStackOrTls(addr, &is_stack)) {
339     ReportLocation *loc =
340         ReportLocation::New(is_stack ? ReportLocationStack : ReportLocationTLS);
341     loc->tid = tctx->tid;
342     rep_->locs.PushBack(loc);
343     AddThread(tctx);
344   }
345   if (ReportLocation *loc = SymbolizeData(addr)) {
346     loc->suppressable = true;
347     rep_->locs.PushBack(loc);
348     return;
349   }
350 #endif
351 }
352 
353 #ifndef SANITIZER_GO
AddSleep(u32 stack_id)354 void ScopedReport::AddSleep(u32 stack_id) {
355   rep_->sleep = SymbolizeStackId(stack_id);
356 }
357 #endif
358 
SetCount(int count)359 void ScopedReport::SetCount(int count) {
360   rep_->count = count;
361 }
362 
GetReport() const363 const ReportDesc *ScopedReport::GetReport() const {
364   return rep_;
365 }
366 
RestoreStack(int tid,const u64 epoch,VarSizeStackTrace * stk,MutexSet * mset)367 void RestoreStack(int tid, const u64 epoch, VarSizeStackTrace *stk,
368                   MutexSet *mset) {
369   // This function restores stack trace and mutex set for the thread/epoch.
370   // It does so by getting stack trace and mutex set at the beginning of
371   // trace part, and then replaying the trace till the given epoch.
372   Trace* trace = ThreadTrace(tid);
373   ReadLock l(&trace->mtx);
374   const int partidx = (epoch / kTracePartSize) % TraceParts();
375   TraceHeader* hdr = &trace->headers[partidx];
376   if (epoch < hdr->epoch0 || epoch >= hdr->epoch0 + kTracePartSize)
377     return;
378   CHECK_EQ(RoundDown(epoch, kTracePartSize), hdr->epoch0);
379   const u64 epoch0 = RoundDown(epoch, TraceSize());
380   const u64 eend = epoch % TraceSize();
381   const u64 ebegin = RoundDown(eend, kTracePartSize);
382   DPrintf("#%d: RestoreStack epoch=%zu ebegin=%zu eend=%zu partidx=%d\n",
383           tid, (uptr)epoch, (uptr)ebegin, (uptr)eend, partidx);
384   Vector<uptr> stack(MBlockReportStack);
385   stack.Resize(hdr->stack0.size + 64);
386   for (uptr i = 0; i < hdr->stack0.size; i++) {
387     stack[i] = hdr->stack0.trace[i];
388     DPrintf2("  #%02zu: pc=%zx\n", i, stack[i]);
389   }
390   if (mset)
391     *mset = hdr->mset0;
392   uptr pos = hdr->stack0.size;
393   Event *events = (Event*)GetThreadTrace(tid);
394   for (uptr i = ebegin; i <= eend; i++) {
395     Event ev = events[i];
396     EventType typ = (EventType)(ev >> 61);
397     uptr pc = (uptr)(ev & ((1ull << 61) - 1));
398     DPrintf2("  %zu typ=%d pc=%zx\n", i, typ, pc);
399     if (typ == EventTypeMop) {
400       stack[pos] = pc;
401     } else if (typ == EventTypeFuncEnter) {
402       if (stack.Size() < pos + 2)
403         stack.Resize(pos + 2);
404       stack[pos++] = pc;
405     } else if (typ == EventTypeFuncExit) {
406       if (pos > 0)
407         pos--;
408     }
409     if (mset) {
410       if (typ == EventTypeLock) {
411         mset->Add(pc, true, epoch0 + i);
412       } else if (typ == EventTypeUnlock) {
413         mset->Del(pc, true);
414       } else if (typ == EventTypeRLock) {
415         mset->Add(pc, false, epoch0 + i);
416       } else if (typ == EventTypeRUnlock) {
417         mset->Del(pc, false);
418       }
419     }
420     for (uptr j = 0; j <= pos; j++)
421       DPrintf2("      #%zu: %zx\n", j, stack[j]);
422   }
423   if (pos == 0 && stack[0] == 0)
424     return;
425   pos++;
426   stk->Init(&stack[0], pos);
427 }
428 
HandleRacyStacks(ThreadState * thr,VarSizeStackTrace traces[2],uptr addr_min,uptr addr_max)429 static bool HandleRacyStacks(ThreadState *thr, VarSizeStackTrace traces[2],
430                              uptr addr_min, uptr addr_max) {
431   bool equal_stack = false;
432   RacyStacks hash;
433   bool equal_address = false;
434   RacyAddress ra0 = {addr_min, addr_max};
435   {
436     ReadLock lock(&ctx->racy_mtx);
437     if (flags()->suppress_equal_stacks) {
438       hash.hash[0] = md5_hash(traces[0].trace, traces[0].size * sizeof(uptr));
439       hash.hash[1] = md5_hash(traces[1].trace, traces[1].size * sizeof(uptr));
440       for (uptr i = 0; i < ctx->racy_stacks.Size(); i++) {
441         if (hash == ctx->racy_stacks[i]) {
442           VPrintf(2,
443               "ThreadSanitizer: suppressing report as doubled (stack)\n");
444           equal_stack = true;
445           break;
446         }
447       }
448     }
449     if (flags()->suppress_equal_addresses) {
450       for (uptr i = 0; i < ctx->racy_addresses.Size(); i++) {
451         RacyAddress ra2 = ctx->racy_addresses[i];
452         uptr maxbeg = max(ra0.addr_min, ra2.addr_min);
453         uptr minend = min(ra0.addr_max, ra2.addr_max);
454         if (maxbeg < minend) {
455           VPrintf(2, "ThreadSanitizer: suppressing report as doubled (addr)\n");
456           equal_address = true;
457           break;
458         }
459       }
460     }
461   }
462   if (!equal_stack && !equal_address)
463     return false;
464   if (!equal_stack) {
465     Lock lock(&ctx->racy_mtx);
466     ctx->racy_stacks.PushBack(hash);
467   }
468   if (!equal_address) {
469     Lock lock(&ctx->racy_mtx);
470     ctx->racy_addresses.PushBack(ra0);
471   }
472   return true;
473 }
474 
AddRacyStacks(ThreadState * thr,VarSizeStackTrace traces[2],uptr addr_min,uptr addr_max)475 static void AddRacyStacks(ThreadState *thr, VarSizeStackTrace traces[2],
476                           uptr addr_min, uptr addr_max) {
477   Lock lock(&ctx->racy_mtx);
478   if (flags()->suppress_equal_stacks) {
479     RacyStacks hash;
480     hash.hash[0] = md5_hash(traces[0].trace, traces[0].size * sizeof(uptr));
481     hash.hash[1] = md5_hash(traces[1].trace, traces[1].size * sizeof(uptr));
482     ctx->racy_stacks.PushBack(hash);
483   }
484   if (flags()->suppress_equal_addresses) {
485     RacyAddress ra0 = {addr_min, addr_max};
486     ctx->racy_addresses.PushBack(ra0);
487   }
488 }
489 
OutputReport(ThreadState * thr,const ScopedReport & srep)490 bool OutputReport(ThreadState *thr, const ScopedReport &srep) {
491   if (!flags()->report_bugs)
492     return false;
493   atomic_store_relaxed(&ctx->last_symbolize_time_ns, NanoTime());
494   const ReportDesc *rep = srep.GetReport();
495   Suppression *supp = 0;
496   uptr pc_or_addr = 0;
497   for (uptr i = 0; pc_or_addr == 0 && i < rep->mops.Size(); i++)
498     pc_or_addr = IsSuppressed(rep->typ, rep->mops[i]->stack, &supp);
499   for (uptr i = 0; pc_or_addr == 0 && i < rep->stacks.Size(); i++)
500     pc_or_addr = IsSuppressed(rep->typ, rep->stacks[i], &supp);
501   for (uptr i = 0; pc_or_addr == 0 && i < rep->threads.Size(); i++)
502     pc_or_addr = IsSuppressed(rep->typ, rep->threads[i]->stack, &supp);
503   for (uptr i = 0; pc_or_addr == 0 && i < rep->locs.Size(); i++)
504     pc_or_addr = IsSuppressed(rep->typ, rep->locs[i], &supp);
505   if (pc_or_addr != 0) {
506     Lock lock(&ctx->fired_suppressions_mtx);
507     FiredSuppression s = {srep.GetReport()->typ, pc_or_addr, supp};
508     ctx->fired_suppressions.push_back(s);
509   }
510   {
511     bool old_is_freeing = thr->is_freeing;
512     thr->is_freeing = false;
513     bool suppressed = OnReport(rep, pc_or_addr != 0);
514     thr->is_freeing = old_is_freeing;
515     if (suppressed)
516       return false;
517   }
518   PrintReport(rep);
519   ctx->nreported++;
520   if (flags()->halt_on_error)
521     Die();
522   return true;
523 }
524 
IsFiredSuppression(Context * ctx,ReportType type,StackTrace trace)525 bool IsFiredSuppression(Context *ctx, ReportType type, StackTrace trace) {
526   ReadLock lock(&ctx->fired_suppressions_mtx);
527   for (uptr k = 0; k < ctx->fired_suppressions.size(); k++) {
528     if (ctx->fired_suppressions[k].type != type)
529       continue;
530     for (uptr j = 0; j < trace.size; j++) {
531       FiredSuppression *s = &ctx->fired_suppressions[k];
532       if (trace.trace[j] == s->pc_or_addr) {
533         if (s->supp)
534           atomic_fetch_add(&s->supp->hit_count, 1, memory_order_relaxed);
535         return true;
536       }
537     }
538   }
539   return false;
540 }
541 
IsFiredSuppression(Context * ctx,ReportType type,uptr addr)542 static bool IsFiredSuppression(Context *ctx, ReportType type, uptr addr) {
543   ReadLock lock(&ctx->fired_suppressions_mtx);
544   for (uptr k = 0; k < ctx->fired_suppressions.size(); k++) {
545     if (ctx->fired_suppressions[k].type != type)
546       continue;
547     FiredSuppression *s = &ctx->fired_suppressions[k];
548     if (addr == s->pc_or_addr) {
549       if (s->supp)
550         atomic_fetch_add(&s->supp->hit_count, 1, memory_order_relaxed);
551       return true;
552     }
553   }
554   return false;
555 }
556 
RaceBetweenAtomicAndFree(ThreadState * thr)557 static bool RaceBetweenAtomicAndFree(ThreadState *thr) {
558   Shadow s0(thr->racy_state[0]);
559   Shadow s1(thr->racy_state[1]);
560   CHECK(!(s0.IsAtomic() && s1.IsAtomic()));
561   if (!s0.IsAtomic() && !s1.IsAtomic())
562     return true;
563   if (s0.IsAtomic() && s1.IsFreed())
564     return true;
565   if (s1.IsAtomic() && thr->is_freeing)
566     return true;
567   return false;
568 }
569 
ReportRace(ThreadState * thr)570 void ReportRace(ThreadState *thr) {
571   CheckNoLocks(thr);
572 
573   // Symbolizer makes lots of intercepted calls. If we try to process them,
574   // at best it will cause deadlocks on internal mutexes.
575   ScopedIgnoreInterceptors ignore;
576 
577   if (!flags()->report_bugs)
578     return;
579   if (!flags()->report_atomic_races && !RaceBetweenAtomicAndFree(thr))
580     return;
581 
582   bool freed = false;
583   {
584     Shadow s(thr->racy_state[1]);
585     freed = s.GetFreedAndReset();
586     thr->racy_state[1] = s.raw();
587   }
588 
589   uptr addr = ShadowToMem((uptr)thr->racy_shadow_addr);
590   uptr addr_min = 0;
591   uptr addr_max = 0;
592   {
593     uptr a0 = addr + Shadow(thr->racy_state[0]).addr0();
594     uptr a1 = addr + Shadow(thr->racy_state[1]).addr0();
595     uptr e0 = a0 + Shadow(thr->racy_state[0]).size();
596     uptr e1 = a1 + Shadow(thr->racy_state[1]).size();
597     addr_min = min(a0, a1);
598     addr_max = max(e0, e1);
599     if (IsExpectedReport(addr_min, addr_max - addr_min))
600       return;
601   }
602 
603   ReportType typ = ReportTypeRace;
604   if (thr->is_vptr_access && freed)
605     typ = ReportTypeVptrUseAfterFree;
606   else if (thr->is_vptr_access)
607     typ = ReportTypeVptrRace;
608   else if (freed)
609     typ = ReportTypeUseAfterFree;
610 
611   if (IsFiredSuppression(ctx, typ, addr))
612     return;
613 
614   const uptr kMop = 2;
615   VarSizeStackTrace traces[kMop];
616   const uptr toppc = TraceTopPC(thr);
617   ObtainCurrentStack(thr, toppc, &traces[0]);
618   if (IsFiredSuppression(ctx, typ, traces[0]))
619     return;
620 
621   // MutexSet is too large to live on stack.
622   Vector<u64> mset_buffer(MBlockScopedBuf);
623   mset_buffer.Resize(sizeof(MutexSet) / sizeof(u64) + 1);
624   MutexSet *mset2 = new(&mset_buffer[0]) MutexSet();
625 
626   Shadow s2(thr->racy_state[1]);
627   RestoreStack(s2.tid(), s2.epoch(), &traces[1], mset2);
628   if (IsFiredSuppression(ctx, typ, traces[1]))
629     return;
630 
631   if (HandleRacyStacks(thr, traces, addr_min, addr_max))
632     return;
633 
634   ThreadRegistryLock l0(ctx->thread_registry);
635   ScopedReport rep(typ);
636   for (uptr i = 0; i < kMop; i++) {
637     Shadow s(thr->racy_state[i]);
638     rep.AddMemoryAccess(addr, s, traces[i], i == 0 ? &thr->mset : mset2);
639   }
640 
641   for (uptr i = 0; i < kMop; i++) {
642     FastState s(thr->racy_state[i]);
643     ThreadContext *tctx = static_cast<ThreadContext*>(
644         ctx->thread_registry->GetThreadLocked(s.tid()));
645     if (s.epoch() < tctx->epoch0 || s.epoch() > tctx->epoch1)
646       continue;
647     rep.AddThread(tctx);
648   }
649 
650   rep.AddLocation(addr_min, addr_max - addr_min);
651 
652 #ifndef SANITIZER_GO
653   {  // NOLINT
654     Shadow s(thr->racy_state[1]);
655     if (s.epoch() <= thr->last_sleep_clock.get(s.tid()))
656       rep.AddSleep(thr->last_sleep_stack_id);
657   }
658 #endif
659 
660   if (!OutputReport(thr, rep))
661     return;
662 
663   AddRacyStacks(thr, traces, addr_min, addr_max);
664 }
665 
PrintCurrentStack(ThreadState * thr,uptr pc)666 void PrintCurrentStack(ThreadState *thr, uptr pc) {
667   VarSizeStackTrace trace;
668   ObtainCurrentStack(thr, pc, &trace);
669   PrintStack(SymbolizeStack(trace));
670 }
671 
PrintCurrentStackSlow(uptr pc)672 void PrintCurrentStackSlow(uptr pc) {
673 #ifndef SANITIZER_GO
674   BufferedStackTrace *ptrace =
675       new(internal_alloc(MBlockStackTrace, sizeof(BufferedStackTrace)))
676           BufferedStackTrace();
677   ptrace->Unwind(kStackTraceMax, pc, 0, 0, 0, 0, false);
678   for (uptr i = 0; i < ptrace->size / 2; i++) {
679     uptr tmp = ptrace->trace_buffer[i];
680     ptrace->trace_buffer[i] = ptrace->trace_buffer[ptrace->size - i - 1];
681     ptrace->trace_buffer[ptrace->size - i - 1] = tmp;
682   }
683   PrintStack(SymbolizeStack(*ptrace));
684 #endif
685 }
686 
687 }  // namespace __tsan
688 
689 using namespace __tsan;
690 
691 extern "C" {
692 SANITIZER_INTERFACE_ATTRIBUTE
__sanitizer_print_stack_trace()693 void __sanitizer_print_stack_trace() {
694   PrintCurrentStackSlow(StackTrace::GetCurrentPc());
695 }
696 }  // extern "C"
697