Bug Summary

File:projects/compiler-rt/lib/tsan/../sanitizer_common/sanitizer_vector.h
Warning:line 47, column 5
Returning null reference

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name tsan_rtl_report.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -pic-is-pie -mthread-model posix -mframe-pointer=none -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -target-feature +sse3 -dwarf-column-info -debugger-tuning=gdb -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-10/lib/clang/10.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-10~svn374814/build-llvm/projects/compiler-rt/lib/tsan -I /build/llvm-toolchain-snapshot-10~svn374814/projects/compiler-rt/lib/tsan -I /build/llvm-toolchain-snapshot-10~svn374814/build-llvm/include -I /build/llvm-toolchain-snapshot-10~svn374814/include -I /build/llvm-toolchain-snapshot-10~svn374814/projects/compiler-rt/lib/tsan/.. -U NDEBUG -isysroot . -internal-isystem ./usr/local/include -internal-isystem /usr/lib/llvm-10/lib/clang/10.0.0/include -internal-externc-isystem ./include -internal-externc-isystem ./usr/include -O3 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -Wno-unused-parameter -Wno-variadic-macros -Wno-non-virtual-dtor -std=c++14 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-10~svn374814/build-llvm/projects/compiler-rt/lib/tsan -fdebug-prefix-map=/build/llvm-toolchain-snapshot-10~svn374814=. -ferror-limit 19 -fmessage-length 0 -fvisibility hidden -fvisibility-inlines-hidden -fno-builtin -fno-rtti -fgnuc-version=4.2.1 -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -o /tmp/scan-build-2019-10-15-035155-28452-1 -x c++ /build/llvm-toolchain-snapshot-10~svn374814/projects/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp

/build/llvm-toolchain-snapshot-10~svn374814/projects/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp

→
1//===-- tsan_rtl_report.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//===----------------------------------------------------------------------===//
12
13#include "sanitizer_common/sanitizer_libc.h"
14#include "sanitizer_common/sanitizer_placement_new.h"
15#include "sanitizer_common/sanitizer_stackdepot.h"
16#include "sanitizer_common/sanitizer_common.h"
17#include "sanitizer_common/sanitizer_stacktrace.h"
18#include "tsan_platform.h"
19#include "tsan_rtl.h"
20#include "tsan_suppressions.h"
21#include "tsan_symbolize.h"
22#include "tsan_report.h"
23#include "tsan_sync.h"
24#include "tsan_mman.h"
25#include "tsan_flags.h"
26#include "tsan_fd.h"
27
28namespace __tsan {
29
30using namespace __sanitizer;
31
32static ReportStack *SymbolizeStack(StackTrace trace);
33
34void TsanCheckFailed(const char *file, int line, const char *cond,
35 u64 v1, u64 v2) {
36 // There is high probability that interceptors will check-fail as well,
37 // on the other hand there is no sense in processing interceptors
38 // since we are going to die soon.
39 ScopedIgnoreInterceptors ignore;
40#if !SANITIZER_GO0
41 cur_thread()->ignore_sync++;
42 cur_thread()->ignore_reads_and_writes++;
43#endif
44 Printf("FATAL: ThreadSanitizer CHECK failed: "
45 "%s:%d \"%s\" (0x%zx, 0x%zx)\n",
46 file, line, cond, (uptr)v1, (uptr)v2);
47 PrintCurrentStackSlow(StackTrace::GetCurrentPc());
48 Die();
49}
50
51// Can be overriden by an application/test to intercept reports.
52#ifdef TSAN_EXTERNAL_HOOKS
53bool OnReport(const ReportDesc *rep, bool suppressed);
54#else
55SANITIZER_WEAK_CXX_DEFAULT_IMPLextern "C++" __attribute__((visibility("default"))) __attribute__
((weak)) __attribute__((noinline))
56bool OnReport(const ReportDesc *rep, bool suppressed) {
57 (void)rep;
58 return suppressed;
59}
60#endif
61
62SANITIZER_WEAK_DEFAULT_IMPLextern "C" __attribute__((visibility("default"))) __attribute__
((weak)) __attribute__((noinline))
63void __tsan_on_report(const ReportDesc *rep) {
64 (void)rep;
65}
66
67static void StackStripMain(SymbolizedStack *frames) {
68 SymbolizedStack *last_frame = nullptr;
69 SymbolizedStack *last_frame2 = nullptr;
70 for (SymbolizedStack *cur = frames; cur; cur = cur->next) {
71 last_frame2 = last_frame;
72 last_frame = cur;
73 }
74
75 if (last_frame2 == 0)
76 return;
77#if !SANITIZER_GO0
78 const char *last = last_frame->info.function;
79 const char *last2 = last_frame2->info.function;
80 // Strip frame above 'main'
81 if (last2 && 0 == internal_strcmp(last2, "main")) {
82 last_frame->ClearAll();
83 last_frame2->next = nullptr;
84 // Strip our internal thread start routine.
85 } else if (last && 0 == internal_strcmp(last, "__tsan_thread_start_func")) {
86 last_frame->ClearAll();
87 last_frame2->next = nullptr;
88 // Strip global ctors init.
89 } else if (last && 0 == internal_strcmp(last, "__do_global_ctors_aux")) {
90 last_frame->ClearAll();
91 last_frame2->next = nullptr;
92 // If both are 0, then we probably just failed to symbolize.
93 } else if (last || last2) {
94 // Ensure that we recovered stack completely. Trimmed stack
95 // can actually happen if we do not instrument some code,
96 // so it's only a debug print. However we must try hard to not miss it
97 // due to our fault.
98 DPrintf("Bottom stack frame is missed\n");
99 }
100#else
101 // The last frame always point into runtime (gosched0, goexit0, runtime.main).
102 last_frame->ClearAll();
103 last_frame2->next = nullptr;
104#endif
105}
106
107ReportStack *SymbolizeStackId(u32 stack_id) {
108 if (stack_id == 0)
109 return 0;
110 StackTrace stack = StackDepotGet(stack_id);
111 if (stack.trace == nullptr)
112 return nullptr;
113 return SymbolizeStack(stack);
114}
115
116static ReportStack *SymbolizeStack(StackTrace trace) {
117 if (trace.size == 0)
118 return 0;
119 SymbolizedStack *top = nullptr;
120 for (uptr si = 0; si < trace.size; si++) {
121 const uptr pc = trace.trace[si];
122 uptr pc1 = pc;
123 // We obtain the return address, but we're interested in the previous
124 // instruction.
125 if ((pc & kExternalPCBit) == 0)
126 pc1 = StackTrace::GetPreviousInstructionPc(pc);
127 SymbolizedStack *ent = SymbolizeCode(pc1);
128 CHECK_NE(ent, 0)do { __sanitizer::u64 v1 = (__sanitizer::u64)((ent)); __sanitizer
::u64 v2 = (__sanitizer::u64)((0)); if (__builtin_expect(!!(!
(v1 != v2)), 0)) __sanitizer::CheckFailed("/build/llvm-toolchain-snapshot-10~svn374814/projects/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp"
, 128, "(" "(ent)" ") " "!=" " (" "(0)" ")", v1, v2); } while
(false);
129 SymbolizedStack *last = ent;
130 while (last->next) {
131 last->info.address = pc; // restore original pc for report
132 last = last->next;
133 }
134 last->info.address = pc; // restore original pc for report
135 last->next = top;
136 top = ent;
137 }
138 StackStripMain(top);
139
140 ReportStack *stack = ReportStack::New();
141 stack->frames = top;
142 return stack;
143}
144
145ScopedReportBase::ScopedReportBase(ReportType typ, uptr tag) {
146 ctx->thread_registry->CheckLocked();
147 void *mem = internal_alloc(MBlockReport, sizeof(ReportDesc));
148 rep_ = new(mem) ReportDesc;
149 rep_->typ = typ;
150 rep_->tag = tag;
151 ctx->report_mtx.Lock();
152}
153
154ScopedReportBase::~ScopedReportBase() {
155 ctx->report_mtx.Unlock();
156 DestroyAndFree(rep_);
157 rep_ = nullptr;
158}
159
160void ScopedReportBase::AddStack(StackTrace stack, bool suppressable) {
161 ReportStack **rs = rep_->stacks.PushBack();
162 *rs = SymbolizeStack(stack);
163 (*rs)->suppressable = suppressable;
164}
165
166void ScopedReportBase::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
188void ScopedReportBase::AddUniqueTid(int unique_tid) {
189 rep_->unique_tids.PushBack(unique_tid);
190}
191
192void ScopedReportBase::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->thread_type = tctx->thread_type;
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_GO0
213static bool FindThreadByUidLockedCallback(ThreadContextBase *tctx, void *arg) {
214 int unique_id = *(int *)arg;
215 return tctx->unique_id == (u32)unique_id;
216}
217
218static 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
225static ThreadContext *FindThreadByTidLocked(int tid) {
226 ctx->thread_registry->CheckLocked();
227 return static_cast<ThreadContext*>(
228 ctx->thread_registry->GetThreadLocked(tid));
229}
230
231static 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)do { __sanitizer::u64 v1 = (__sanitizer::u64)((thr)); __sanitizer
::u64 v2 = (__sanitizer::u64)(0); if (__builtin_expect(!!(!(v1
!= v2)), 0)) __sanitizer::CheckFailed("/build/llvm-toolchain-snapshot-10~svn374814/projects/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp"
, 237, "(" "(thr)" ") " "!=" " (" "0" ")", v1, v2); } while (
false);
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
242ThreadContext *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)do { __sanitizer::u64 v1 = (__sanitizer::u64)((thr)); __sanitizer
::u64 v2 = (__sanitizer::u64)(0); if (__builtin_expect(!!(!(v1
!= v2)), 0)) __sanitizer::CheckFailed("/build/llvm-toolchain-snapshot-10~svn374814/projects/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp"
, 250, "(" "(thr)" ") " "!=" " (" "0" ")", v1, v2); } while (
false);
251 *is_stack = (addr >= thr->stk_addr && addr < thr->stk_addr + thr->stk_size);
252 return tctx;
253}
254#endif
255
256void ScopedReportBase::AddThread(int unique_tid, bool suppressable) {
257#if !SANITIZER_GO0
258 if (const ThreadContext *tctx = FindThreadByUidLocked(unique_tid))
259 AddThread(tctx, suppressable);
260#endif
261}
262
263void ScopedReportBase::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
277u64 ScopedReportBase::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
296void ScopedReportBase::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
310void ScopedReportBase::AddLocation(uptr addr, uptr size) {
311 if (addr == 0)
312 return;
313#if !SANITIZER_GO0
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_GO0
365void ScopedReportBase::AddSleep(u32 stack_id) {
366 rep_->sleep = SymbolizeStackId(stack_id);
367}
368#endif
369
370void ScopedReportBase::SetCount(int count) { rep_->count = count; }
371
372const ReportDesc *ScopedReportBase::GetReport() const { return rep_; }
373
374ScopedReport::ScopedReport(ReportType typ, uptr tag)
375 : ScopedReportBase(typ, tag) {}
376
377ScopedReport::~ScopedReport() {}
378
379void RestoreStack(int tid, const u64 epoch, VarSizeStackTrace *stk,
380 MutexSet *mset, uptr *tag) {
381 // This function restores stack trace and mutex set for the thread/epoch.
382 // It does so by getting stack trace and mutex set at the beginning of
383 // trace part, and then replaying the trace till the given epoch.
384 Trace* trace = ThreadTrace(tid);
385 ReadLock l(&trace->mtx);
386 const int partidx = (epoch / kTracePartSize) % TraceParts();
387 TraceHeader* hdr = &trace->headers[partidx];
388 if (epoch < hdr->epoch0 || epoch >= hdr->epoch0 + kTracePartSize)
17
←
Assuming 'epoch' is >= field 'epoch0'
→
18
←
Assuming the condition is false
→
19
←
Taking false branch
→
389 return;
390 CHECK_EQ(RoundDown(epoch, kTracePartSize), hdr->epoch0)do { __sanitizer::u64 v1 = (__sanitizer::u64)((RoundDown(epoch
, kTracePartSize))); __sanitizer::u64 v2 = (__sanitizer::u64)
((hdr->epoch0)); if (__builtin_expect(!!(!(v1 == v2)), 0))
__sanitizer::CheckFailed("/build/llvm-toolchain-snapshot-10~svn374814/projects/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp"
, 390, "(" "(RoundDown(epoch, kTracePartSize))" ") " "==" " ("
"(hdr->epoch0)" ")", v1, v2); } while (false);
20
←
Assuming 'v1' is equal to 'v2'
→
21
←
Taking false branch
→
22
←
Loop condition is false. Exiting loop
→
391 const u64 epoch0 = RoundDown(epoch, TraceSize());
392 const u64 eend = epoch % TraceSize();
393 const u64 ebegin = RoundDown(eend, kTracePartSize);
394 DPrintf("#%d: RestoreStack epoch=%zu ebegin=%zu eend=%zu partidx=%d\n",
395 tid, (uptr)epoch, (uptr)ebegin, (uptr)eend, partidx);
396 Vector<uptr> stack;
23
←
Calling default constructor for 'Vector<unsigned long>'
→
25
←
Returning from default constructor for 'Vector<unsigned long>'
→
397 stack.Resize(hdr->stack0.size + 64);
398 for (uptr i = 0; i < hdr->stack0.size; i++) {
26
←
Loop condition is true. Entering loop body
→
399 stack[i] = hdr->stack0.trace[i];
27
←
Calling 'Vector::operator[]'
→
400 DPrintf2(" #%02zu: pc=%zx\n", i, stack[i]);
401 }
402 if (mset)
403 *mset = hdr->mset0;
404 uptr pos = hdr->stack0.size;
405 Event *events = (Event*)GetThreadTrace(tid);
406 for (uptr i = ebegin; i <= eend; i++) {
407 Event ev = events[i];
408 EventType typ = (EventType)(ev >> kEventPCBits);
409 uptr pc = (uptr)(ev & ((1ull << kEventPCBits) - 1));
410 DPrintf2(" %zu typ=%d pc=%zx\n", i, typ, pc);
411 if (typ == EventTypeMop) {
412 stack[pos] = pc;
413 } else if (typ == EventTypeFuncEnter) {
414 if (stack.Size() < pos + 2)
415 stack.Resize(pos + 2);
416 stack[pos++] = pc;
417 } else if (typ == EventTypeFuncExit) {
418 if (pos > 0)
419 pos--;
420 }
421 if (mset) {
422 if (typ == EventTypeLock) {
423 mset->Add(pc, true, epoch0 + i);
424 } else if (typ == EventTypeUnlock) {
425 mset->Del(pc, true);
426 } else if (typ == EventTypeRLock) {
427 mset->Add(pc, false, epoch0 + i);
428 } else if (typ == EventTypeRUnlock) {
429 mset->Del(pc, false);
430 }
431 }
432 for (uptr j = 0; j <= pos; j++)
433 DPrintf2(" #%zu: %zx\n", j, stack[j]);
434 }
435 if (pos == 0 && stack[0] == 0)
436 return;
437 pos++;
438 stk->Init(&stack[0], pos);
439 ExtractTagFromStack(stk, tag);
440}
441
442static bool HandleRacyStacks(ThreadState *thr, VarSizeStackTrace traces[2],
443 uptr addr_min, uptr addr_max) {
444 bool equal_stack = false;
445 RacyStacks hash;
446 bool equal_address = false;
447 RacyAddress ra0 = {addr_min, addr_max};
448 {
449 ReadLock lock(&ctx->racy_mtx);
450 if (flags()->suppress_equal_stacks) {
451 hash.hash[0] = md5_hash(traces[0].trace, traces[0].size * sizeof(uptr));
452 hash.hash[1] = md5_hash(traces[1].trace, traces[1].size * sizeof(uptr));
453 for (uptr i = 0; i < ctx->racy_stacks.Size(); i++) {
454 if (hash == ctx->racy_stacks[i]) {
455 VPrintf(2,do { if ((uptr)Verbosity() >= (2)) Printf("ThreadSanitizer: suppressing report as doubled (stack)\n"
); } while (0)
456 "ThreadSanitizer: suppressing report as doubled (stack)\n")do { if ((uptr)Verbosity() >= (2)) Printf("ThreadSanitizer: suppressing report as doubled (stack)\n"
); } while (0);
457 equal_stack = true;
458 break;
459 }
460 }
461 }
462 if (flags()->suppress_equal_addresses) {
463 for (uptr i = 0; i < ctx->racy_addresses.Size(); i++) {
464 RacyAddress ra2 = ctx->racy_addresses[i];
465 uptr maxbeg = max(ra0.addr_min, ra2.addr_min);
466 uptr minend = min(ra0.addr_max, ra2.addr_max);
467 if (maxbeg < minend) {
468 VPrintf(2, "ThreadSanitizer: suppressing report as doubled (addr)\n")do { if ((uptr)Verbosity() >= (2)) Printf("ThreadSanitizer: suppressing report as doubled (addr)\n"
); } while (0);
469 equal_address = true;
470 break;
471 }
472 }
473 }
474 }
475 if (!equal_stack && !equal_address)
476 return false;
477 if (!equal_stack) {
478 Lock lock(&ctx->racy_mtx);
479 ctx->racy_stacks.PushBack(hash);
480 }
481 if (!equal_address) {
482 Lock lock(&ctx->racy_mtx);
483 ctx->racy_addresses.PushBack(ra0);
484 }
485 return true;
486}
487
488static void AddRacyStacks(ThreadState *thr, VarSizeStackTrace traces[2],
489 uptr addr_min, uptr addr_max) {
490 Lock lock(&ctx->racy_mtx);
491 if (flags()->suppress_equal_stacks) {
492 RacyStacks hash;
493 hash.hash[0] = md5_hash(traces[0].trace, traces[0].size * sizeof(uptr));
494 hash.hash[1] = md5_hash(traces[1].trace, traces[1].size * sizeof(uptr));
495 ctx->racy_stacks.PushBack(hash);
496 }
497 if (flags()->suppress_equal_addresses) {
498 RacyAddress ra0 = {addr_min, addr_max};
499 ctx->racy_addresses.PushBack(ra0);
500 }
501}
502
503bool OutputReport(ThreadState *thr, const ScopedReport &srep) {
504 if (!flags()->report_bugs || thr->suppress_reports)
505 return false;
506 atomic_store_relaxed(&ctx->last_symbolize_time_ns, NanoTime());
507 const ReportDesc *rep = srep.GetReport();
508 CHECK_EQ(thr->current_report, nullptr)do { __sanitizer::u64 v1 = (__sanitizer::u64)((thr->current_report
)); __sanitizer::u64 v2 = (__sanitizer::u64)((nullptr)); if (
__builtin_expect(!!(!(v1 == v2)), 0)) __sanitizer::CheckFailed
("/build/llvm-toolchain-snapshot-10~svn374814/projects/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp"
, 508, "(" "(thr->current_report)" ") " "==" " (" "(nullptr)"
")", v1, v2); } while (false);
509 thr->current_report = rep;
510 Suppression *supp = 0;
511 uptr pc_or_addr = 0;
512 for (uptr i = 0; pc_or_addr == 0 && i < rep->mops.Size(); i++)
513 pc_or_addr = IsSuppressed(rep->typ, rep->mops[i]->stack, &supp);
514 for (uptr i = 0; pc_or_addr == 0 && i < rep->stacks.Size(); i++)
515 pc_or_addr = IsSuppressed(rep->typ, rep->stacks[i], &supp);
516 for (uptr i = 0; pc_or_addr == 0 && i < rep->threads.Size(); i++)
517 pc_or_addr = IsSuppressed(rep->typ, rep->threads[i]->stack, &supp);
518 for (uptr i = 0; pc_or_addr == 0 && i < rep->locs.Size(); i++)
519 pc_or_addr = IsSuppressed(rep->typ, rep->locs[i], &supp);
520 if (pc_or_addr != 0) {
521 Lock lock(&ctx->fired_suppressions_mtx);
522 FiredSuppression s = {srep.GetReport()->typ, pc_or_addr, supp};
523 ctx->fired_suppressions.push_back(s);
524 }
525 {
526 bool old_is_freeing = thr->is_freeing;
527 thr->is_freeing = false;
528 bool suppressed = OnReport(rep, pc_or_addr != 0);
529 thr->is_freeing = old_is_freeing;
530 if (suppressed) {
531 thr->current_report = nullptr;
532 return false;
533 }
534 }
535 PrintReport(rep);
536 __tsan_on_report(rep);
537 ctx->nreported++;
538 if (flags()->halt_on_error)
539 Die();
540 thr->current_report = nullptr;
541 return true;
542}
543
544bool IsFiredSuppression(Context *ctx, ReportType type, StackTrace trace) {
545 ReadLock lock(&ctx->fired_suppressions_mtx);
546 for (uptr k = 0; k < ctx->fired_suppressions.size(); k++) {
547 if (ctx->fired_suppressions[k].type != type)
548 continue;
549 for (uptr j = 0; j < trace.size; j++) {
550 FiredSuppression *s = &ctx->fired_suppressions[k];
551 if (trace.trace[j] == s->pc_or_addr) {
552 if (s->supp)
553 atomic_fetch_add(&s->supp->hit_count, 1, memory_order_relaxed);
554 return true;
555 }
556 }
557 }
558 return false;
559}
560
561static bool IsFiredSuppression(Context *ctx, ReportType type, uptr addr) {
562 ReadLock lock(&ctx->fired_suppressions_mtx);
563 for (uptr k = 0; k < ctx->fired_suppressions.size(); k++) {
564 if (ctx->fired_suppressions[k].type != type)
565 continue;
566 FiredSuppression *s = &ctx->fired_suppressions[k];
567 if (addr == s->pc_or_addr) {
568 if (s->supp)
569 atomic_fetch_add(&s->supp->hit_count, 1, memory_order_relaxed);
570 return true;
571 }
572 }
573 return false;
574}
575
576static bool RaceBetweenAtomicAndFree(ThreadState *thr) {
577 Shadow s0(thr->racy_state[0]);
578 Shadow s1(thr->racy_state[1]);
579 CHECK(!(s0.IsAtomic() && s1.IsAtomic()))do { __sanitizer::u64 v1 = (__sanitizer::u64)((!(s0.IsAtomic(
) && s1.IsAtomic()))); __sanitizer::u64 v2 = (__sanitizer
::u64)(0); if (__builtin_expect(!!(!(v1 != v2)), 0)) __sanitizer
::CheckFailed("/build/llvm-toolchain-snapshot-10~svn374814/projects/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp"
, 579, "(" "(!(s0.IsAtomic() && s1.IsAtomic()))" ") "
"!=" " (" "0" ")", v1, v2); } while (false);
580 if (!s0.IsAtomic() && !s1.IsAtomic())
581 return true;
582 if (s0.IsAtomic() && s1.IsFreed())
583 return true;
584 if (s1.IsAtomic() && thr->is_freeing)
585 return true;
586 return false;
587}
588
589void ReportRace(ThreadState *thr) {
590 CheckNoLocks(thr);
591
592 // Symbolizer makes lots of intercepted calls. If we try to process them,
593 // at best it will cause deadlocks on internal mutexes.
594 ScopedIgnoreInterceptors ignore;
595
596 if (!flags()->report_bugs)
1
Assuming field 'report_bugs' is true
→
2
←
Taking false branch
→
597 return;
598 if (!flags()->report_atomic_races && !RaceBetweenAtomicAndFree(thr))
3
←
Assuming field 'report_atomic_races' is true
→
599 return;
600
601 bool freed = false;
602 {
603 Shadow s(thr->racy_state[1]);
604 freed = s.GetFreedAndReset();
605 thr->racy_state[1] = s.raw();
606 }
607
608 uptr addr = ShadowToMem((uptr)thr->racy_shadow_addr);
609 uptr addr_min = 0;
610 uptr addr_max = 0;
611 {
612 uptr a0 = addr + Shadow(thr->racy_state[0]).addr0();
613 uptr a1 = addr + Shadow(thr->racy_state[1]).addr0();
614 uptr e0 = a0 + Shadow(thr->racy_state[0]).size();
615 uptr e1 = a1 + Shadow(thr->racy_state[1]).size();
616 addr_min = min(a0, a1);
617 addr_max = max(e0, e1);
618 if (IsExpectedReport(addr_min, addr_max - addr_min))
4
←
Assuming the condition is false
→
5
←
Taking false branch
→
619 return;
620 }
621
622 ReportType typ = ReportTypeRace;
623 if (thr->is_vptr_access && freed)
6
←
Assuming field 'is_vptr_access' is false
→
624 typ = ReportTypeVptrUseAfterFree;
625 else if (thr->is_vptr_access
6.1
Field 'is_vptr_access' is false
6.1
Field 'is_vptr_access' is false
)
7
←
Taking false branch
→
626 typ = ReportTypeVptrRace;
627 else if (freed)
8
←
Assuming 'freed' is false
→
9
←
Taking false branch
→
628 typ = ReportTypeUseAfterFree;
629
630 if (IsFiredSuppression(ctx, typ, addr))
10
←
Assuming the condition is false
→
11
←
Taking false branch
→
631 return;
632
633 const uptr kMop = 2;
634 VarSizeStackTrace traces[kMop];
635 uptr tags[kMop] = {kExternalTagNone};
636 uptr toppc = TraceTopPC(thr);
637 if (toppc >> kEventPCBits) {
12
←
Assuming the condition is false
→
13
←
Taking false branch
→
638 // This is a work-around for a known issue.
639 // The scenario where this happens is rather elaborate and requires
640 // an instrumented __sanitizer_report_error_summary callback and
641 // a __tsan_symbolize_external callback and a race during a range memory
642 // access larger than 8 bytes. MemoryAccessRange adds the current PC to
643 // the trace and starts processing memory accesses. A first memory access
644 // triggers a race, we report it and call the instrumented
645 // __sanitizer_report_error_summary, which adds more stuff to the trace
646 // since it is intrumented. Then a second memory access in MemoryAccessRange
647 // also triggers a race and we get here and call TraceTopPC to get the
648 // current PC, however now it contains some unrelated events from the
649 // callback. Most likely, TraceTopPC will now return a EventTypeFuncExit
650 // event. Later we subtract -1 from it (in GetPreviousInstructionPc)
651 // and the resulting PC has kExternalPCBit set, so we pass it to
652 // __tsan_symbolize_external_ex. __tsan_symbolize_external_ex is within its
653 // rights to crash since the PC is completely bogus.
654 // test/tsan/double_race.cpp contains a test case for this.
655 toppc = 0;
656 }
657 ObtainCurrentStack(thr, toppc, &traces[0], &tags[0]);
658 if (IsFiredSuppression(ctx, typ, traces[0]))
14
←
Assuming the condition is false
→
15
←
Taking false branch
→
659 return;
660
661 // MutexSet is too large to live on stack.
662 Vector<u64> mset_buffer;
663 mset_buffer.Resize(sizeof(MutexSet) / sizeof(u64) + 1);
664 MutexSet *mset2 = new(&mset_buffer[0]) MutexSet();
665
666 Shadow s2(thr->racy_state[1]);
667 RestoreStack(s2.tid(), s2.epoch(), &traces[1], mset2, &tags[1]);
16
←
Calling 'RestoreStack'
→
668 if (IsFiredSuppression(ctx, typ, traces[1]))
669 return;
670
671 if (HandleRacyStacks(thr, traces, addr_min, addr_max))
672 return;
673
674 // If any of the accesses has a tag, treat this as an "external" race.
675 uptr tag = kExternalTagNone;
676 for (uptr i = 0; i < kMop; i++) {
677 if (tags[i] != kExternalTagNone) {
678 typ = ReportTypeExternalRace;
679 tag = tags[i];
680 break;
681 }
682 }
683
684 ThreadRegistryLock l0(ctx->thread_registry);
685 ScopedReport rep(typ, tag);
686 for (uptr i = 0; i < kMop; i++) {
687 Shadow s(thr->racy_state[i]);
688 rep.AddMemoryAccess(addr, tags[i], s, traces[i],
689 i == 0 ? &thr->mset : mset2);
690 }
691
692 for (uptr i = 0; i < kMop; i++) {
693 FastState s(thr->racy_state[i]);
694 ThreadContext *tctx = static_cast<ThreadContext*>(
695 ctx->thread_registry->GetThreadLocked(s.tid()));
696 if (s.epoch() < tctx->epoch0 || s.epoch() > tctx->epoch1)
697 continue;
698 rep.AddThread(tctx);
699 }
700
701 rep.AddLocation(addr_min, addr_max - addr_min);
702
703#if !SANITIZER_GO0
704 {
705 Shadow s(thr->racy_state[1]);
706 if (s.epoch() <= thr->last_sleep_clock.get(s.tid()))
707 rep.AddSleep(thr->last_sleep_stack_id);
708 }
709#endif
710
711 if (!OutputReport(thr, rep))
712 return;
713
714 AddRacyStacks(thr, traces, addr_min, addr_max);
715}
716
717void PrintCurrentStack(ThreadState *thr, uptr pc) {
718 VarSizeStackTrace trace;
719 ObtainCurrentStack(thr, pc, &trace);
720 PrintStack(SymbolizeStack(trace));
721}
722
723// Always inlining PrintCurrentStackSlow, because LocatePcInTrace assumes
724// __sanitizer_print_stack_trace exists in the actual unwinded stack, but
725// tail-call to PrintCurrentStackSlow breaks this assumption because
726// __sanitizer_print_stack_trace disappears after tail-call.
727// However, this solution is not reliable enough, please see dvyukov's comment
728// http://reviews.llvm.org/D19148#406208
729// Also see PR27280 comment 2 and 3 for breaking examples and analysis.
730ALWAYS_INLINEinline __attribute__((always_inline))
731void PrintCurrentStackSlow(uptr pc) {
732#if !SANITIZER_GO0
733 uptr bp = GET_CURRENT_FRAME()(__sanitizer::uptr) __builtin_frame_address(0);
734 BufferedStackTrace *ptrace =
735 new(internal_alloc(MBlockStackTrace, sizeof(BufferedStackTrace)))
736 BufferedStackTrace();
737 ptrace->Unwind(pc, bp, nullptr, false);
738
739 for (uptr i = 0; i < ptrace->size / 2; i++) {
740 uptr tmp = ptrace->trace_buffer[i];
741 ptrace->trace_buffer[i] = ptrace->trace_buffer[ptrace->size - i - 1];
742 ptrace->trace_buffer[ptrace->size - i - 1] = tmp;
743 }
744 PrintStack(SymbolizeStack(*ptrace));
745#endif
746}
747
748} // namespace __tsan
749
750using namespace __tsan;
751
752extern "C" {
753SANITIZER_INTERFACE_ATTRIBUTE__attribute__((visibility("default")))
754void __sanitizer_print_stack_trace() {
755 PrintCurrentStackSlow(StackTrace::GetCurrentPc());
756}
757} // extern "C"
←

/build/llvm-toolchain-snapshot-10~svn374814/projects/compiler-rt/lib/tsan/../sanitizer_common/sanitizer_vector.h

1//===-- sanitizer_vector.h -------------------------------------*- C++ -*-===//
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 shared between sanitizers run-time libraries.
10//
11//===----------------------------------------------------------------------===//
12
13// Low-fat STL-like vector container.
14
15#ifndef SANITIZER_VECTOR_H
16#define SANITIZER_VECTOR_H
17
18#include "sanitizer_common/sanitizer_allocator_internal.h"
19#include "sanitizer_common/sanitizer_libc.h"
20
21namespace __sanitizer {
22
23template<typename T>
24class Vector {
25 public:
26 Vector() : begin_(), end_(), last_() {}
24
←
Null pointer value stored to 'stack.begin_'
→
27
28 ~Vector() {
29 if (begin_)
30 InternalFree(begin_);
31 }
32
33 void Reset() {
34 if (begin_)
35 InternalFree(begin_);
36 begin_ = 0;
37 end_ = 0;
38 last_ = 0;
39 }
40
41 uptr Size() const {
42 return end_ - begin_;
43 }
44
45 T &operator[](uptr i) {
46 DCHECK_LT(i, end_ - begin_);
47 return begin_[i];
28
←
Returning null reference
48 }
49
50 const T &operator[](uptr i) const {
51 DCHECK_LT(i, end_ - begin_);
52 return begin_[i];
53 }
54
55 T *PushBack() {
56 EnsureSize(Size() + 1);
57 T *p = &end_[-1];
58 internal_memset(p, 0, sizeof(*p));
59 return p;
60 }
61
62 T *PushBack(const T& v) {
63 EnsureSize(Size() + 1);
64 T *p = &end_[-1];
65 internal_memcpy(p, &v, sizeof(*p));
66 return p;
67 }
68
69 void PopBack() {
70 DCHECK_GT(end_, begin_);
71 end_--;
72 }
73
74 void Resize(uptr size) {
75 if (size == 0) {
76 end_ = begin_;
77 return;
78 }
79 uptr old_size = Size();
80 if (size <= old_size) {
81 end_ = begin_ + size;
82 return;
83 }
84 EnsureSize(size);
85 if (old_size < size) {
86 for (uptr i = old_size; i < size; i++)
87 internal_memset(&begin_[i], 0, sizeof(begin_[i]));
88 }
89 }
90
91 private:
92 T *begin_;
93 T *end_;
94 T *last_;
95
96 void EnsureSize(uptr size) {
97 if (size <= Size())
98 return;
99 if (size <= (uptr)(last_ - begin_)) {
100 end_ = begin_ + size;
101 return;
102 }
103 uptr cap0 = last_ - begin_;
104 uptr cap = cap0 * 5 / 4; // 25% growth
105 if (cap == 0)
106 cap = 16;
107 if (cap < size)
108 cap = size;
109 T *p = (T*)InternalAlloc(cap * sizeof(T));
110 if (cap0) {
111 internal_memcpy(p, begin_, cap0 * sizeof(T));
112 InternalFree(begin_);
113 }
114 begin_ = p;
115 end_ = begin_ + size;
116 last_ = begin_ + cap;
117 }
118
119 Vector(const Vector&);
120 void operator=(const Vector&);
121};
122} // namespace __sanitizer
123
124#endif // #ifndef SANITIZER_VECTOR_H