libsanitizer/tsan/tsan_rtl_thread.cpp

   1 //===-- tsan_rtl_thread.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_placement_new.h"
  14 #include "tsan_rtl.h"
  15 #include "tsan_mman.h"
  16 #include "tsan_platform.h"
  17 #include "tsan_report.h"
  18 #include "tsan_sync.h"
  19
  20 namespace __tsan {
  21
  22 // ThreadContext implementation.
  23
  24 ThreadContext::ThreadContext(int tid)
  25   : ThreadContextBase(tid)
  26   , thr()
  27   , sync()
  28   , epoch0()
  29   , epoch1() {
  30 }
  31
  32 #if !SANITIZER_GO
  33 ThreadContext::~ThreadContext() {
  34 }
  35 #endif
  36
  37 void ThreadContext::OnDead() {
  38   CHECK_EQ(sync.size(), 0);
  39 }
  40
  41 void ThreadContext::OnJoined(void *arg) {
  42   ThreadState *caller_thr = static_cast<ThreadState *>(arg);
  43   AcquireImpl(caller_thr, 0, &sync);
  44   sync.Reset(&caller_thr->proc()->clock_cache);
  45 }
  46
  47 struct OnCreatedArgs {
  48   ThreadState *thr;
  49   uptr pc;
  50 };
  51
  52 void ThreadContext::OnCreated(void *arg) {
  53   thr = 0;
  54   if (tid == 0)
  55     return;
  56   OnCreatedArgs *args = static_cast<OnCreatedArgs *>(arg);
  57   if (!args->thr)  // GCD workers don't have a parent thread.
  58     return;
  59   args->thr->fast_state.IncrementEpoch();
  60   // Can't increment epoch w/o writing to the trace as well.
  61   TraceAddEvent(args->thr, args->thr->fast_state, EventTypeMop, 0);
  62   ReleaseImpl(args->thr, 0, &sync);
  63   creation_stack_id = CurrentStackId(args->thr, args->pc);
  64   if (reuse_count == 0)
  65     StatInc(args->thr, StatThreadMaxTid);
  66 }
  67
  68 void ThreadContext::OnReset() {
  69   CHECK_EQ(sync.size(), 0);
  70   uptr trace_p = GetThreadTrace(tid);
  71   ReleaseMemoryPagesToOS(trace_p, trace_p + TraceSize() * sizeof(Event));
  72   //!!! ReleaseMemoryToOS(GetThreadTraceHeader(tid), sizeof(Trace));
  73 }
  74
  75 void ThreadContext::OnDetached(void *arg) {
  76   ThreadState *thr1 = static_cast<ThreadState*>(arg);
  77   sync.Reset(&thr1->proc()->clock_cache);
  78 }
  79
  80 struct OnStartedArgs {
  81   ThreadState *thr;
  82   uptr stk_addr;
  83   uptr stk_size;
  84   uptr tls_addr;
  85   uptr tls_size;
  86 };
  87
  88 void ThreadContext::OnStarted(void *arg) {
  89   OnStartedArgs *args = static_cast<OnStartedArgs*>(arg);
  90   thr = args->thr;
  91   // RoundUp so that one trace part does not contain events
  92   // from different threads.
  93   epoch0 = RoundUp(epoch1 + 1, kTracePartSize);
  94   epoch1 = (u64)-1;
  95   new(thr) ThreadState(ctx, tid, unique_id, epoch0, reuse_count,
  96       args->stk_addr, args->stk_size, args->tls_addr, args->tls_size);
  97 #if !SANITIZER_GO
  98   thr->shadow_stack = &ThreadTrace(thr->tid)->shadow_stack[0];
  99   thr->shadow_stack_pos = thr->shadow_stack;
 100   thr->shadow_stack_end = thr->shadow_stack + kShadowStackSize;
 101 #else
 102   // Setup dynamic shadow stack.
 103   const int kInitStackSize = 8;
 104   thr->shadow_stack = (uptr*)internal_alloc(MBlockShadowStack,
 105       kInitStackSize * sizeof(uptr));
 106   thr->shadow_stack_pos = thr->shadow_stack;
 107   thr->shadow_stack_end = thr->shadow_stack + kInitStackSize;
 108 #endif
 109   if (common_flags()->detect_deadlocks)
 110     thr->dd_lt = ctx->dd->CreateLogicalThread(unique_id);
 111   thr->fast_state.SetHistorySize(flags()->history_size);
 112   // Commit switch to the new part of the trace.
 113   // TraceAddEvent will reset stack0/mset0 in the new part for us.
 114   TraceAddEvent(thr, thr->fast_state, EventTypeMop, 0);
 115
 116   thr->fast_synch_epoch = epoch0;
 117   AcquireImpl(thr, 0, &sync);
 118   StatInc(thr, StatSyncAcquire);
 119   sync.Reset(&thr->proc()->clock_cache);
 120   thr->is_inited = true;
 121   DPrintf("#%d: ThreadStart epoch=%zu stk_addr=%zx stk_size=%zx "
 122           "tls_addr=%zx tls_size=%zx\n",
 123           tid, (uptr)epoch0, args->stk_addr, args->stk_size,
 124           args->tls_addr, args->tls_size);
 125 }
 126
 127 void ThreadContext::OnFinished() {
 128 #if SANITIZER_GO
 129   internal_free(thr->shadow_stack);
 130   thr->shadow_stack = nullptr;
 131   thr->shadow_stack_pos = nullptr;
 132   thr->shadow_stack_end = nullptr;
 133 #endif
 134   if (!detached) {
 135     thr->fast_state.IncrementEpoch();
 136     // Can't increment epoch w/o writing to the trace as well.
 137     TraceAddEvent(thr, thr->fast_state, EventTypeMop, 0);
 138     ReleaseImpl(thr, 0, &sync);
 139   }
 140   epoch1 = thr->fast_state.epoch();
 141
 142   if (common_flags()->detect_deadlocks)
 143     ctx->dd->DestroyLogicalThread(thr->dd_lt);
 144   thr->clock.ResetCached(&thr->proc()->clock_cache);
 145 #if !SANITIZER_GO
 146   thr->last_sleep_clock.ResetCached(&thr->proc()->clock_cache);
 147 #endif
 148 #if !SANITIZER_GO
 149   PlatformCleanUpThreadState(thr);
 150 #endif
 151   thr->~ThreadState();
 152 #if TSAN_COLLECT_STATS
 153   StatAggregate(ctx->stat, thr->stat);
 154 #endif
 155   thr = 0;
 156 }
 157
 158 #if !SANITIZER_GO
 159 struct ThreadLeak {
 160   ThreadContext *tctx;
 161   int count;
 162 };
 163
 164 static void MaybeReportThreadLeak(ThreadContextBase *tctx_base, void *arg) {
 165   Vector<ThreadLeak> &leaks = *(Vector<ThreadLeak>*)arg;
 166   ThreadContext *tctx = static_cast<ThreadContext*>(tctx_base);
 167   if (tctx->detached || tctx->status != ThreadStatusFinished)
 168     return;
 169   for (uptr i = 0; i < leaks.Size(); i++) {
 170     if (leaks[i].tctx->creation_stack_id == tctx->creation_stack_id) {
 171       leaks[i].count++;
 172       return;
 173     }
 174   }
 175   ThreadLeak leak = {tctx, 1};
 176   leaks.PushBack(leak);
 177 }
 178 #endif
 179
 180 #if !SANITIZER_GO
 181 static void ReportIgnoresEnabled(ThreadContext *tctx, IgnoreSet *set) {
 182   if (tctx->tid == 0) {
 183     Printf("ThreadSanitizer: main thread finished with ignores enabled\n");
 184   } else {
 185     Printf("ThreadSanitizer: thread T%d %s finished with ignores enabled,"
 186       " created at:\n", tctx->tid, tctx->name);
 187     PrintStack(SymbolizeStackId(tctx->creation_stack_id));
 188   }
 189   Printf("  One of the following ignores was not ended"
 190       " (in order of probability)\n");
 191   for (uptr i = 0; i < set->Size(); i++) {
 192     Printf("  Ignore was enabled at:\n");
 193     PrintStack(SymbolizeStackId(set->At(i)));
 194   }
 195   Die();
 196 }
 197
 198 static void ThreadCheckIgnore(ThreadState *thr) {
 199   if (ctx->after_multithreaded_fork)
 200     return;
 201   if (thr->ignore_reads_and_writes)
 202     ReportIgnoresEnabled(thr->tctx, &thr->mop_ignore_set);
 203   if (thr->ignore_sync)
 204     ReportIgnoresEnabled(thr->tctx, &thr->sync_ignore_set);
 205 }
 206 #else
 207 static void ThreadCheckIgnore(ThreadState *thr) {}
 208 #endif
 209
 210 void ThreadFinalize(ThreadState *thr) {
 211   ThreadCheckIgnore(thr);
 212 #if !SANITIZER_GO
 213   if (!flags()->report_thread_leaks)
 214     return;
 215   ThreadRegistryLock l(ctx->thread_registry);
 216   Vector<ThreadLeak> leaks;
 217   ctx->thread_registry->RunCallbackForEachThreadLocked(
 218       MaybeReportThreadLeak, &leaks);
 219   for (uptr i = 0; i < leaks.Size(); i++) {
 220     ScopedReport rep(ReportTypeThreadLeak);
 221     rep.AddThread(leaks[i].tctx, true);
 222     rep.SetCount(leaks[i].count);
 223     OutputReport(thr, rep);
 224   }
 225 #endif
 226 }
 227
 228 int ThreadCount(ThreadState *thr) {
 229   uptr result;
 230   ctx->thread_registry->GetNumberOfThreads(0, 0, &result);
 231   return (int)result;
 232 }
 233
 234 int ThreadCreate(ThreadState *thr, uptr pc, uptr uid, bool detached) {
 235   StatInc(thr, StatThreadCreate);
 236   OnCreatedArgs args = { thr, pc };
 237   u32 parent_tid = thr ? thr->tid : kInvalidTid;  // No parent for GCD workers.
 238   int tid =
 239       ctx->thread_registry->CreateThread(uid, detached, parent_tid, &args);
 240   DPrintf("#%d: ThreadCreate tid=%d uid=%zu\n", parent_tid, tid, uid);
 241   StatSet(thr, StatThreadMaxAlive, ctx->thread_registry->GetMaxAliveThreads());
 242   return tid;
 243 }
 244
 245 void ThreadStart(ThreadState *thr, int tid, tid_t os_id,
 246                  ThreadType thread_type) {
 247   uptr stk_addr = 0;
 248   uptr stk_size = 0;
 249   uptr tls_addr = 0;
 250   uptr tls_size = 0;
 251 #if !SANITIZER_GO
 252   if (thread_type != ThreadType::Fiber)
 253     GetThreadStackAndTls(tid == 0, &stk_addr, &stk_size, &tls_addr, &tls_size);
 254
 255   if (tid) {
 256     if (stk_addr && stk_size)
 257       MemoryRangeImitateWrite(thr, /*pc=*/ 1, stk_addr, stk_size);
 258
 259     if (tls_addr && tls_size) ImitateTlsWrite(thr, tls_addr, tls_size);
 260   }
 261 #endif
 262
 263   ThreadRegistry *tr = ctx->thread_registry;
 264   OnStartedArgs args = { thr, stk_addr, stk_size, tls_addr, tls_size };
 265   tr->StartThread(tid, os_id, thread_type, &args);
 266
 267   tr->Lock();
 268   thr->tctx = (ThreadContext*)tr->GetThreadLocked(tid);
 269   tr->Unlock();
 270
 271 #if !SANITIZER_GO
 272   if (ctx->after_multithreaded_fork) {
 273     thr->ignore_interceptors++;
 274     ThreadIgnoreBegin(thr, 0);
 275     ThreadIgnoreSyncBegin(thr, 0);
 276   }
 277 #endif
 278 }
 279
 280 void ThreadFinish(ThreadState *thr) {
 281   ThreadCheckIgnore(thr);
 282   StatInc(thr, StatThreadFinish);
 283   if (thr->stk_addr && thr->stk_size)
 284     DontNeedShadowFor(thr->stk_addr, thr->stk_size);
 285   if (thr->tls_addr && thr->tls_size)
 286     DontNeedShadowFor(thr->tls_addr, thr->tls_size);
 287   thr->is_dead = true;
 288   ctx->thread_registry->FinishThread(thr->tid);
 289 }
 290
 291 struct ConsumeThreadContext {
 292   uptr uid;
 293   ThreadContextBase *tctx;
 294 };
 295
 296 static bool ConsumeThreadByUid(ThreadContextBase *tctx, void *arg) {
 297   ConsumeThreadContext *findCtx = (ConsumeThreadContext *)arg;
 298   if (tctx->user_id == findCtx->uid && tctx->status != ThreadStatusInvalid) {
 299     if (findCtx->tctx) {
 300       // Ensure that user_id is unique. If it's not the case we are screwed.
 301       // Something went wrong before, but now there is no way to recover.
 302       // Returning a wrong thread is not an option, it may lead to very hard
 303       // to debug false positives (e.g. if we join a wrong thread).
 304       Report("ThreadSanitizer: dup thread with used id 0x%zx\n", findCtx->uid);
 305       Die();
 306     }
 307     findCtx->tctx = tctx;
 308     tctx->user_id = 0;
 309   }
 310   return false;
 311 }
 312
 313 int ThreadConsumeTid(ThreadState *thr, uptr pc, uptr uid) {
 314   ConsumeThreadContext findCtx = {uid, nullptr};
 315   ctx->thread_registry->FindThread(ConsumeThreadByUid, &findCtx);
 316   int tid = findCtx.tctx ? findCtx.tctx->tid : ThreadRegistry::kUnknownTid;
 317   DPrintf("#%d: ThreadTid uid=%zu tid=%d\n", thr->tid, uid, tid);
 318   return tid;
 319 }
 320
 321 void ThreadJoin(ThreadState *thr, uptr pc, int tid) {
 322   CHECK_GT(tid, 0);
 323   CHECK_LT(tid, kMaxTid);
 324   DPrintf("#%d: ThreadJoin tid=%d\n", thr->tid, tid);
 325   ctx->thread_registry->JoinThread(tid, thr);
 326 }
 327
 328 void ThreadDetach(ThreadState *thr, uptr pc, int tid) {
 329   CHECK_GT(tid, 0);
 330   CHECK_LT(tid, kMaxTid);
 331   ctx->thread_registry->DetachThread(tid, thr);
 332 }
 333
 334 void ThreadNotJoined(ThreadState *thr, uptr pc, int tid, uptr uid) {
 335   CHECK_GT(tid, 0);
 336   CHECK_LT(tid, kMaxTid);
 337   ctx->thread_registry->SetThreadUserId(tid, uid);
 338 }
 339
 340 void ThreadSetName(ThreadState *thr, const char *name) {
 341   ctx->thread_registry->SetThreadName(thr->tid, name);
 342 }
 343
 344 void MemoryAccessRange(ThreadState *thr, uptr pc, uptr addr,
 345                        uptr size, bool is_write) {
 346   if (size == 0)
 347     return;
 348
 349   u64 *shadow_mem = (u64*)MemToShadow(addr);
 350   DPrintf2("#%d: MemoryAccessRange: @%p %p size=%d is_write=%d\n",
 351       thr->tid, (void*)pc, (void*)addr,
 352       (int)size, is_write);
 353
 354 #if SANITIZER_DEBUG
 355   if (!IsAppMem(addr)) {
 356     Printf("Access to non app mem %zx\n", addr);
 357     DCHECK(IsAppMem(addr));
 358   }
 359   if (!IsAppMem(addr + size - 1)) {
 360     Printf("Access to non app mem %zx\n", addr + size - 1);
 361     DCHECK(IsAppMem(addr + size - 1));
 362   }
 363   if (!IsShadowMem((uptr)shadow_mem)) {
 364     Printf("Bad shadow addr %p (%zx)\n", shadow_mem, addr);
 365     DCHECK(IsShadowMem((uptr)shadow_mem));
 366   }
 367   if (!IsShadowMem((uptr)(shadow_mem + size * kShadowCnt / 8 - 1))) {
 368     Printf("Bad shadow addr %p (%zx)\n",
 369                shadow_mem + size * kShadowCnt / 8 - 1, addr + size - 1);
 370     DCHECK(IsShadowMem((uptr)(shadow_mem + size * kShadowCnt / 8 - 1)));
 371   }
 372 #endif
 373
 374   StatInc(thr, StatMopRange);
 375
 376   if (*shadow_mem == kShadowRodata) {
 377     DCHECK(!is_write);
 378     // Access to .rodata section, no races here.
 379     // Measurements show that it can be 10-20% of all memory accesses.
 380     StatInc(thr, StatMopRangeRodata);
 381     return;
 382   }
 383
 384   FastState fast_state = thr->fast_state;
 385   if (fast_state.GetIgnoreBit())
 386     return;
 387
 388   fast_state.IncrementEpoch();
 389   thr->fast_state = fast_state;
 390   TraceAddEvent(thr, fast_state, EventTypeMop, pc);
 391
 392   bool unaligned = (addr % kShadowCell) != 0;
 393
 394   // Handle unaligned beginning, if any.
 395   for (; addr % kShadowCell && size; addr++, size--) {
 396     int const kAccessSizeLog = 0;
 397     Shadow cur(fast_state);
 398     cur.SetWrite(is_write);
 399     cur.SetAddr0AndSizeLog(addr & (kShadowCell - 1), kAccessSizeLog);
 400     MemoryAccessImpl(thr, addr, kAccessSizeLog, is_write, false,
 401         shadow_mem, cur);
 402   }
 403   if (unaligned)
 404     shadow_mem += kShadowCnt;
 405   // Handle middle part, if any.
 406   for (; size >= kShadowCell; addr += kShadowCell, size -= kShadowCell) {
 407     int const kAccessSizeLog = 3;
 408     Shadow cur(fast_state);
 409     cur.SetWrite(is_write);
 410     cur.SetAddr0AndSizeLog(0, kAccessSizeLog);
 411     MemoryAccessImpl(thr, addr, kAccessSizeLog, is_write, false,
 412         shadow_mem, cur);
 413     shadow_mem += kShadowCnt;
 414   }
 415   // Handle ending, if any.
 416   for (; size; addr++, size--) {
 417     int const kAccessSizeLog = 0;
 418     Shadow cur(fast_state);
 419     cur.SetWrite(is_write);
 420     cur.SetAddr0AndSizeLog(addr & (kShadowCell - 1), kAccessSizeLog);
 421     MemoryAccessImpl(thr, addr, kAccessSizeLog, is_write, false,
 422         shadow_mem, cur);
 423   }
 424 }
 425
 426 #if !SANITIZER_GO
 427 void FiberSwitchImpl(ThreadState *from, ThreadState *to) {
 428   Processor *proc = from->proc();
 429   ProcUnwire(proc, from);
 430   ProcWire(proc, to);
 431   set_cur_thread(to);
 432 }
 433
 434 ThreadState *FiberCreate(ThreadState *thr, uptr pc, unsigned flags) {
 435   void *mem = internal_alloc(MBlockThreadContex, sizeof(ThreadState));
 436   ThreadState *fiber = static_cast<ThreadState *>(mem);
 437   internal_memset(fiber, 0, sizeof(*fiber));
 438   int tid = ThreadCreate(thr, pc, 0, true);
 439   FiberSwitchImpl(thr, fiber);
 440   ThreadStart(fiber, tid, 0, ThreadType::Fiber);
 441   FiberSwitchImpl(fiber, thr);
 442   return fiber;
 443 }
 444
 445 void FiberDestroy(ThreadState *thr, uptr pc, ThreadState *fiber) {
 446   FiberSwitchImpl(thr, fiber);
 447   ThreadFinish(fiber);
 448   FiberSwitchImpl(fiber, thr);
 449   internal_free(fiber);
 450 }
 451
 452 void FiberSwitch(ThreadState *thr, uptr pc,
 453                  ThreadState *fiber, unsigned flags) {
 454   if (!(flags & FiberSwitchFlagNoSync))
 455     Release(thr, pc, (uptr)fiber);
 456   FiberSwitchImpl(thr, fiber);
 457   if (!(flags & FiberSwitchFlagNoSync))
 458     Acquire(fiber, pc, (uptr)fiber);
 459 }
 460 #endif
 461
 462 }  // namespace __tsan