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(Tid tid) : ThreadContextBase(tid), thr(), sync() {}
  25
  26 #if !SANITIZER_GO
  27 ThreadContext::~ThreadContext() {
  28 }
  29 #endif
  30
  31 void ThreadContext::OnReset() { CHECK(!sync); }
  32
  33 #if !SANITIZER_GO
  34 struct ThreadLeak {
  35   ThreadContext *tctx;
  36   int count;
  37 };
  38
  39 static void CollectThreadLeaks(ThreadContextBase *tctx_base, void *arg) {
  40   auto &leaks = *static_cast<Vector<ThreadLeak> *>(arg);
  41   auto *tctx = static_cast<ThreadContext *>(tctx_base);
  42   if (tctx->detached || tctx->status != ThreadStatusFinished)
  43     return;
  44   for (uptr i = 0; i < leaks.Size(); i++) {
  45     if (leaks[i].tctx->creation_stack_id == tctx->creation_stack_id) {
  46       leaks[i].count++;
  47       return;
  48     }
  49   }
  50   leaks.PushBack({tctx, 1});
  51 }
  52 #endif
  53
  54 // Disabled on Mac because lldb test TestTsanBasic fails:
  55 // https://reviews.llvm.org/D112603#3163158
  56 #if !SANITIZER_GO && !SANITIZER_APPLE
  57 static void ReportIgnoresEnabled(ThreadContext *tctx, IgnoreSet *set) {
  58   if (tctx->tid == kMainTid) {
  59     Printf("ThreadSanitizer: main thread finished with ignores enabled\n");
  60   } else {
  61     Printf("ThreadSanitizer: thread T%d %s finished with ignores enabled,"
  62       " created at:\n", tctx->tid, tctx->name);
  63     PrintStack(SymbolizeStackId(tctx->creation_stack_id));
  64   }
  65   Printf("  One of the following ignores was not ended"
  66       " (in order of probability)\n");
  67   for (uptr i = 0; i < set->Size(); i++) {
  68     Printf("  Ignore was enabled at:\n");
  69     PrintStack(SymbolizeStackId(set->At(i)));
  70   }
  71   Die();
  72 }
  73
  74 static void ThreadCheckIgnore(ThreadState *thr) {
  75   if (ctx->after_multithreaded_fork)
  76     return;
  77   if (thr->ignore_reads_and_writes)
  78     ReportIgnoresEnabled(thr->tctx, &thr->mop_ignore_set);
  79   if (thr->ignore_sync)
  80     ReportIgnoresEnabled(thr->tctx, &thr->sync_ignore_set);
  81 }
  82 #else
  83 static void ThreadCheckIgnore(ThreadState *thr) {}
  84 #endif
  85
  86 void ThreadFinalize(ThreadState *thr) {
  87   ThreadCheckIgnore(thr);
  88 #if !SANITIZER_GO
  89   if (!ShouldReport(thr, ReportTypeThreadLeak))
  90     return;
  91   ThreadRegistryLock l(&ctx->thread_registry);
  92   Vector<ThreadLeak> leaks;
  93   ctx->thread_registry.RunCallbackForEachThreadLocked(CollectThreadLeaks,
  94                                                       &leaks);
  95   for (uptr i = 0; i < leaks.Size(); i++) {
  96     ScopedReport rep(ReportTypeThreadLeak);
  97     rep.AddThread(leaks[i].tctx, true);
  98     rep.SetCount(leaks[i].count);
  99     OutputReport(thr, rep);
 100   }
 101 #endif
 102 }
 103
 104 int ThreadCount(ThreadState *thr) {
 105   uptr result;
 106   ctx->thread_registry.GetNumberOfThreads(0, 0, &result);
 107   return (int)result;
 108 }
 109
 110 struct OnCreatedArgs {
 111   VectorClock *sync;
 112   uptr sync_epoch;
 113   StackID stack;
 114 };
 115
 116 Tid ThreadCreate(ThreadState *thr, uptr pc, uptr uid, bool detached) {
 117   // The main thread and GCD workers don't have a parent thread.
 118   Tid parent = kInvalidTid;
 119   OnCreatedArgs arg = {nullptr, 0, kInvalidStackID};
 120   if (thr) {
 121     parent = thr->tid;
 122     arg.stack = CurrentStackId(thr, pc);
 123     if (!thr->ignore_sync) {
 124       SlotLocker locker(thr);
 125       thr->clock.ReleaseStore(&arg.sync);
 126       arg.sync_epoch = ctx->global_epoch;
 127       IncrementEpoch(thr);
 128     }
 129   }
 130   Tid tid = ctx->thread_registry.CreateThread(uid, detached, parent, &arg);
 131   DPrintf("#%d: ThreadCreate tid=%d uid=%zu\n", parent, tid, uid);
 132   return tid;
 133 }
 134
 135 void ThreadContext::OnCreated(void *arg) {
 136   OnCreatedArgs *args = static_cast<OnCreatedArgs *>(arg);
 137   sync = args->sync;
 138   sync_epoch = args->sync_epoch;
 139   creation_stack_id = args->stack;
 140 }
 141
 142 extern "C" void __tsan_stack_initialization() {}
 143
 144 struct OnStartedArgs {
 145   ThreadState *thr;
 146   uptr stk_addr;
 147   uptr stk_size;
 148   uptr tls_addr;
 149   uptr tls_size;
 150 };
 151
 152 void ThreadStart(ThreadState *thr, Tid tid, tid_t os_id,
 153                  ThreadType thread_type) {
 154   ctx->thread_registry.StartThread(tid, os_id, thread_type, thr);
 155   if (!thr->ignore_sync) {
 156     SlotAttachAndLock(thr);
 157     if (thr->tctx->sync_epoch == ctx->global_epoch)
 158       thr->clock.Acquire(thr->tctx->sync);
 159     SlotUnlock(thr);
 160   }
 161   Free(thr->tctx->sync);
 162
 163   uptr stk_addr = 0;
 164   uptr stk_size = 0;
 165   uptr tls_addr = 0;
 166   uptr tls_size = 0;
 167 #if !SANITIZER_GO
 168   if (thread_type != ThreadType::Fiber)
 169     GetThreadStackAndTls(tid == kMainTid, &stk_addr, &stk_size, &tls_addr,
 170                          &tls_size);
 171 #endif
 172   thr->stk_addr = stk_addr;
 173   thr->stk_size = stk_size;
 174   thr->tls_addr = tls_addr;
 175   thr->tls_size = tls_size;
 176
 177 #if !SANITIZER_GO
 178   if (ctx->after_multithreaded_fork) {
 179     thr->ignore_interceptors++;
 180     ThreadIgnoreBegin(thr, 0);
 181     ThreadIgnoreSyncBegin(thr, 0);
 182   }
 183 #endif
 184
 185 #if !SANITIZER_GO
 186   // Don't imitate stack/TLS writes for the main thread,
 187   // because its initialization is synchronized with all
 188   // subsequent threads anyway.
 189   if (tid != kMainTid) {
 190     if (stk_addr && stk_size) {
 191       const uptr pc = StackTrace::GetNextInstructionPc(
 192           reinterpret_cast<uptr>(__tsan_stack_initialization));
 193       MemoryRangeImitateWrite(thr, pc, stk_addr, stk_size);
 194     }
 195
 196     if (tls_addr && tls_size)
 197       ImitateTlsWrite(thr, tls_addr, tls_size);
 198   }
 199 #endif
 200 }
 201
 202 void ThreadContext::OnStarted(void *arg) {
 203   thr = static_cast<ThreadState *>(arg);
 204   DPrintf("#%d: ThreadStart\n", tid);
 205   new (thr) ThreadState(tid);
 206   if (common_flags()->detect_deadlocks)
 207     thr->dd_lt = ctx->dd->CreateLogicalThread(tid);
 208   thr->tctx = this;
 209 #if !SANITIZER_GO
 210   thr->is_inited = true;
 211 #endif
 212 }
 213
 214 void ThreadFinish(ThreadState *thr) {
 215   DPrintf("#%d: ThreadFinish\n", thr->tid);
 216   ThreadCheckIgnore(thr);
 217   if (thr->stk_addr && thr->stk_size)
 218     DontNeedShadowFor(thr->stk_addr, thr->stk_size);
 219   if (thr->tls_addr && thr->tls_size)
 220     DontNeedShadowFor(thr->tls_addr, thr->tls_size);
 221   thr->is_dead = true;
 222 #if !SANITIZER_GO
 223   thr->is_inited = false;
 224   thr->ignore_interceptors++;
 225   PlatformCleanUpThreadState(thr);
 226 #endif
 227   if (!thr->ignore_sync) {
 228     SlotLocker locker(thr);
 229     ThreadRegistryLock lock(&ctx->thread_registry);
 230     // Note: detached is protected by the thread registry mutex,
 231     // the thread may be detaching concurrently in another thread.
 232     if (!thr->tctx->detached) {
 233       thr->clock.ReleaseStore(&thr->tctx->sync);
 234       thr->tctx->sync_epoch = ctx->global_epoch;
 235       IncrementEpoch(thr);
 236     }
 237   }
 238 #if !SANITIZER_GO
 239   UnmapOrDie(thr->shadow_stack, kShadowStackSize * sizeof(uptr));
 240 #else
 241   Free(thr->shadow_stack);
 242 #endif
 243   thr->shadow_stack = nullptr;
 244   thr->shadow_stack_pos = nullptr;
 245   thr->shadow_stack_end = nullptr;
 246   if (common_flags()->detect_deadlocks)
 247     ctx->dd->DestroyLogicalThread(thr->dd_lt);
 248   SlotDetach(thr);
 249   ctx->thread_registry.FinishThread(thr->tid);
 250   thr->~ThreadState();
 251 }
 252
 253 void ThreadContext::OnFinished() {
 254   Lock lock(&ctx->slot_mtx);
 255   Lock lock1(&trace.mtx);
 256   // Queue all trace parts into the global recycle queue.
 257   auto parts = &trace.parts;
 258   while (trace.local_head) {
 259     CHECK(parts->Queued(trace.local_head));
 260     ctx->trace_part_recycle.PushBack(trace.local_head);
 261     trace.local_head = parts->Next(trace.local_head);
 262   }
 263   ctx->trace_part_recycle_finished += parts->Size();
 264   if (ctx->trace_part_recycle_finished > Trace::kFinishedThreadHi) {
 265     ctx->trace_part_finished_excess += parts->Size();
 266     trace.parts_allocated = 0;
 267   } else if (ctx->trace_part_recycle_finished > Trace::kFinishedThreadLo &&
 268              parts->Size() > 1) {
 269     ctx->trace_part_finished_excess += parts->Size() - 1;
 270     trace.parts_allocated = 1;
 271   }
 272   // From now on replay will use trace->final_pos.
 273   trace.final_pos = (Event *)atomic_load_relaxed(&thr->trace_pos);
 274   atomic_store_relaxed(&thr->trace_pos, 0);
 275   thr->tctx = nullptr;
 276   thr = nullptr;
 277 }
 278
 279 struct ConsumeThreadContext {
 280   uptr uid;
 281   ThreadContextBase *tctx;
 282 };
 283
 284 Tid ThreadConsumeTid(ThreadState *thr, uptr pc, uptr uid) {
 285   return ctx->thread_registry.ConsumeThreadUserId(uid);
 286 }
 287
 288 struct JoinArg {
 289   VectorClock *sync;
 290   uptr sync_epoch;
 291 };
 292
 293 void ThreadJoin(ThreadState *thr, uptr pc, Tid tid) {
 294   CHECK_GT(tid, 0);
 295   DPrintf("#%d: ThreadJoin tid=%d\n", thr->tid, tid);
 296   JoinArg arg = {};
 297   ctx->thread_registry.JoinThread(tid, &arg);
 298   if (!thr->ignore_sync) {
 299     SlotLocker locker(thr);
 300     if (arg.sync_epoch == ctx->global_epoch)
 301       thr->clock.Acquire(arg.sync);
 302   }
 303   Free(arg.sync);
 304 }
 305
 306 void ThreadContext::OnJoined(void *ptr) {
 307   auto arg = static_cast<JoinArg *>(ptr);
 308   arg->sync = sync;
 309   arg->sync_epoch = sync_epoch;
 310   sync = nullptr;
 311   sync_epoch = 0;
 312 }
 313
 314 void ThreadContext::OnDead() { CHECK_EQ(sync, nullptr); }
 315
 316 void ThreadDetach(ThreadState *thr, uptr pc, Tid tid) {
 317   CHECK_GT(tid, 0);
 318   ctx->thread_registry.DetachThread(tid, thr);
 319 }
 320
 321 void ThreadContext::OnDetached(void *arg) { Free(sync); }
 322
 323 void ThreadNotJoined(ThreadState *thr, uptr pc, Tid tid, uptr uid) {
 324   CHECK_GT(tid, 0);
 325   ctx->thread_registry.SetThreadUserId(tid, uid);
 326 }
 327
 328 void ThreadSetName(ThreadState *thr, const char *name) {
 329   ctx->thread_registry.SetThreadName(thr->tid, name);
 330 }
 331
 332 #if !SANITIZER_GO
 333 void FiberSwitchImpl(ThreadState *from, ThreadState *to) {
 334   Processor *proc = from->proc();
 335   ProcUnwire(proc, from);
 336   ProcWire(proc, to);
 337   set_cur_thread(to);
 338 }
 339
 340 ThreadState *FiberCreate(ThreadState *thr, uptr pc, unsigned flags) {
 341   void *mem = Alloc(sizeof(ThreadState));
 342   ThreadState *fiber = static_cast<ThreadState *>(mem);
 343   internal_memset(fiber, 0, sizeof(*fiber));
 344   Tid tid = ThreadCreate(thr, pc, 0, true);
 345   FiberSwitchImpl(thr, fiber);
 346   ThreadStart(fiber, tid, 0, ThreadType::Fiber);
 347   FiberSwitchImpl(fiber, thr);
 348   return fiber;
 349 }
 350
 351 void FiberDestroy(ThreadState *thr, uptr pc, ThreadState *fiber) {
 352   FiberSwitchImpl(thr, fiber);
 353   ThreadFinish(fiber);
 354   FiberSwitchImpl(fiber, thr);
 355   Free(fiber);
 356 }
 357
 358 void FiberSwitch(ThreadState *thr, uptr pc,
 359                  ThreadState *fiber, unsigned flags) {
 360   if (!(flags & FiberSwitchFlagNoSync))
 361     Release(thr, pc, (uptr)fiber);
 362   FiberSwitchImpl(thr, fiber);
 363   if (!(flags & FiberSwitchFlagNoSync))
 364     Acquire(fiber, pc, (uptr)fiber);
 365 }
 366 #endif
 367
 368 }  // namespace __tsan