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      1 //===-- tsan_rtl_thread.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_placement_new.h"
     15 #include "tsan_rtl.h"
     16 #include "tsan_mman.h"
     17 #include "tsan_platform.h"
     18 #include "tsan_report.h"
     19 #include "tsan_sync.h"
     20 
     21 namespace __tsan {
     22 
     23 // ThreadContext implementation.
     24 
     25 ThreadContext::ThreadContext(int tid)
     26   : ThreadContextBase(tid)
     27   , thr()
     28   , sync()
     29   , epoch0()
     30   , epoch1() {
     31 }
     32 
     33 #ifndef SANITIZER_GO
     34 ThreadContext::~ThreadContext() {
     35 }
     36 #endif
     37 
     38 void ThreadContext::OnDead() {
     39   CHECK_EQ(sync.size(), 0);
     40 }
     41 
     42 void ThreadContext::OnJoined(void *arg) {
     43   ThreadState *caller_thr = static_cast<ThreadState *>(arg);
     44   AcquireImpl(caller_thr, 0, &sync);
     45   sync.Reset(&caller_thr->clock_cache);
     46 }
     47 
     48 struct OnCreatedArgs {
     49   ThreadState *thr;
     50   uptr pc;
     51 };
     52 
     53 void ThreadContext::OnCreated(void *arg) {
     54   thr = 0;
     55   if (tid == 0)
     56     return;
     57   OnCreatedArgs *args = static_cast<OnCreatedArgs *>(arg);
     58   args->thr->fast_state.IncrementEpoch();
     59   // Can't increment epoch w/o writing to the trace as well.
     60   TraceAddEvent(args->thr, args->thr->fast_state, EventTypeMop, 0);
     61   ReleaseImpl(args->thr, 0, &sync);
     62   creation_stack_id = CurrentStackId(args->thr, args->pc);
     63   if (reuse_count == 0)
     64     StatInc(args->thr, StatThreadMaxTid);
     65 }
     66 
     67 void ThreadContext::OnReset() {
     68   CHECK_EQ(sync.size(), 0);
     69   FlushUnneededShadowMemory(GetThreadTrace(tid), TraceSize() * sizeof(Event));
     70   //!!! FlushUnneededShadowMemory(GetThreadTraceHeader(tid), sizeof(Trace));
     71 }
     72 
     73 void ThreadContext::OnDetached(void *arg) {
     74   ThreadState *thr1 = static_cast<ThreadState*>(arg);
     75   sync.Reset(&thr1->clock_cache);
     76 }
     77 
     78 struct OnStartedArgs {
     79   ThreadState *thr;
     80   uptr stk_addr;
     81   uptr stk_size;
     82   uptr tls_addr;
     83   uptr tls_size;
     84 };
     85 
     86 void ThreadContext::OnStarted(void *arg) {
     87   OnStartedArgs *args = static_cast<OnStartedArgs*>(arg);
     88   thr = args->thr;
     89   // RoundUp so that one trace part does not contain events
     90   // from different threads.
     91   epoch0 = RoundUp(epoch1 + 1, kTracePartSize);
     92   epoch1 = (u64)-1;
     93   new(thr) ThreadState(ctx, tid, unique_id, epoch0, reuse_count,
     94       args->stk_addr, args->stk_size, args->tls_addr, args->tls_size);
     95 #ifndef SANITIZER_GO
     96   thr->shadow_stack = &ThreadTrace(thr->tid)->shadow_stack[0];
     97   thr->shadow_stack_pos = thr->shadow_stack;
     98   thr->shadow_stack_end = thr->shadow_stack + kShadowStackSize;
     99 #else
    100   // Setup dynamic shadow stack.
    101   const int kInitStackSize = 8;
    102   thr->shadow_stack = (uptr*)internal_alloc(MBlockShadowStack,
    103       kInitStackSize * sizeof(uptr));
    104   thr->shadow_stack_pos = thr->shadow_stack;
    105   thr->shadow_stack_end = thr->shadow_stack + kInitStackSize;
    106 #endif
    107 #ifndef SANITIZER_GO
    108   AllocatorThreadStart(thr);
    109 #endif
    110   if (common_flags()->detect_deadlocks) {
    111     thr->dd_pt = ctx->dd->CreatePhysicalThread();
    112     thr->dd_lt = ctx->dd->CreateLogicalThread(unique_id);
    113   }
    114   thr->fast_state.SetHistorySize(flags()->history_size);
    115   // Commit switch to the new part of the trace.
    116   // TraceAddEvent will reset stack0/mset0 in the new part for us.
    117   TraceAddEvent(thr, thr->fast_state, EventTypeMop, 0);
    118 
    119   thr->fast_synch_epoch = epoch0;
    120   AcquireImpl(thr, 0, &sync);
    121   StatInc(thr, StatSyncAcquire);
    122   sync.Reset(&thr->clock_cache);
    123   thr->is_inited = true;
    124   DPrintf("#%d: ThreadStart epoch=%zu stk_addr=%zx stk_size=%zx "
    125           "tls_addr=%zx tls_size=%zx\n",
    126           tid, (uptr)epoch0, args->stk_addr, args->stk_size,
    127           args->tls_addr, args->tls_size);
    128 }
    129 
    130 void ThreadContext::OnFinished() {
    131   if (!detached) {
    132     thr->fast_state.IncrementEpoch();
    133     // Can't increment epoch w/o writing to the trace as well.
    134     TraceAddEvent(thr, thr->fast_state, EventTypeMop, 0);
    135     ReleaseImpl(thr, 0, &sync);
    136   }
    137   epoch1 = thr->fast_state.epoch();
    138 
    139   if (common_flags()->detect_deadlocks) {
    140     ctx->dd->DestroyPhysicalThread(thr->dd_pt);
    141     ctx->dd->DestroyLogicalThread(thr->dd_lt);
    142   }
    143   ctx->clock_alloc.FlushCache(&thr->clock_cache);
    144   ctx->metamap.OnThreadIdle(thr);
    145 #ifndef SANITIZER_GO
    146   AllocatorThreadFinish(thr);
    147 #endif
    148   thr->~ThreadState();
    149 #if TSAN_COLLECT_STATS
    150   StatAggregate(ctx->stat, thr->stat);
    151 #endif
    152   thr = 0;
    153 }
    154 
    155 #ifndef SANITIZER_GO
    156 struct ThreadLeak {
    157   ThreadContext *tctx;
    158   int count;
    159 };
    160 
    161 static void MaybeReportThreadLeak(ThreadContextBase *tctx_base, void *arg) {
    162   Vector<ThreadLeak> &leaks = *(Vector<ThreadLeak>*)arg;
    163   ThreadContext *tctx = static_cast<ThreadContext*>(tctx_base);
    164   if (tctx->detached || tctx->status != ThreadStatusFinished)
    165     return;
    166   for (uptr i = 0; i < leaks.Size(); i++) {
    167     if (leaks[i].tctx->creation_stack_id == tctx->creation_stack_id) {
    168       leaks[i].count++;
    169       return;
    170     }
    171   }
    172   ThreadLeak leak = {tctx, 1};
    173   leaks.PushBack(leak);
    174 }
    175 #endif
    176 
    177 #ifndef SANITIZER_GO
    178 static void ReportIgnoresEnabled(ThreadContext *tctx, IgnoreSet *set) {
    179   if (tctx->tid == 0) {
    180     Printf("ThreadSanitizer: main thread finished with ignores enabled\n");
    181   } else {
    182     Printf("ThreadSanitizer: thread T%d %s finished with ignores enabled,"
    183       " created at:\n", tctx->tid, tctx->name);
    184     PrintStack(SymbolizeStackId(tctx->creation_stack_id));
    185   }
    186   Printf("  One of the following ignores was not ended"
    187       " (in order of probability)\n");
    188   for (uptr i = 0; i < set->Size(); i++) {
    189     Printf("  Ignore was enabled at:\n");
    190     PrintStack(SymbolizeStackId(set->At(i)));
    191   }
    192   Die();
    193 }
    194 
    195 static void ThreadCheckIgnore(ThreadState *thr) {
    196   if (ctx->after_multithreaded_fork)
    197     return;
    198   if (thr->ignore_reads_and_writes)
    199     ReportIgnoresEnabled(thr->tctx, &thr->mop_ignore_set);
    200   if (thr->ignore_sync)
    201     ReportIgnoresEnabled(thr->tctx, &thr->sync_ignore_set);
    202 }
    203 #else
    204 static void ThreadCheckIgnore(ThreadState *thr) {}
    205 #endif
    206 
    207 void ThreadFinalize(ThreadState *thr) {
    208   ThreadCheckIgnore(thr);
    209 #ifndef SANITIZER_GO
    210   if (!flags()->report_thread_leaks)
    211     return;
    212   ThreadRegistryLock l(ctx->thread_registry);
    213   Vector<ThreadLeak> leaks(MBlockScopedBuf);
    214   ctx->thread_registry->RunCallbackForEachThreadLocked(
    215       MaybeReportThreadLeak, &leaks);
    216   for (uptr i = 0; i < leaks.Size(); i++) {
    217     ScopedReport rep(ReportTypeThreadLeak);
    218     rep.AddThread(leaks[i].tctx, true);
    219     rep.SetCount(leaks[i].count);
    220     OutputReport(thr, rep);
    221   }
    222 #endif
    223 }
    224 
    225 int ThreadCount(ThreadState *thr) {
    226   uptr result;
    227   ctx->thread_registry->GetNumberOfThreads(0, 0, &result);
    228   return (int)result;
    229 }
    230 
    231 int ThreadCreate(ThreadState *thr, uptr pc, uptr uid, bool detached) {
    232   StatInc(thr, StatThreadCreate);
    233   OnCreatedArgs args = { thr, pc };
    234   int tid = ctx->thread_registry->CreateThread(uid, detached, thr->tid, &args);
    235   DPrintf("#%d: ThreadCreate tid=%d uid=%zu\n", thr->tid, tid, uid);
    236   StatSet(thr, StatThreadMaxAlive, ctx->thread_registry->GetMaxAliveThreads());
    237   return tid;
    238 }
    239 
    240 void ThreadStart(ThreadState *thr, int tid, uptr os_id) {
    241   uptr stk_addr = 0;
    242   uptr stk_size = 0;
    243   uptr tls_addr = 0;
    244   uptr tls_size = 0;
    245 #ifndef SANITIZER_GO
    246   GetThreadStackAndTls(tid == 0, &stk_addr, &stk_size, &tls_addr, &tls_size);
    247 
    248   if (tid) {
    249     if (stk_addr && stk_size)
    250       MemoryRangeImitateWrite(thr, /*pc=*/ 1, stk_addr, stk_size);
    251 
    252     if (tls_addr && tls_size) {
    253       // Check that the thr object is in tls;
    254       const uptr thr_beg = (uptr)thr;
    255       const uptr thr_end = (uptr)thr + sizeof(*thr);
    256       CHECK_GE(thr_beg, tls_addr);
    257       CHECK_LE(thr_beg, tls_addr + tls_size);
    258       CHECK_GE(thr_end, tls_addr);
    259       CHECK_LE(thr_end, tls_addr + tls_size);
    260       // Since the thr object is huge, skip it.
    261       MemoryRangeImitateWrite(thr, /*pc=*/ 2, tls_addr, thr_beg - tls_addr);
    262       MemoryRangeImitateWrite(thr, /*pc=*/ 2,
    263           thr_end, tls_addr + tls_size - thr_end);
    264     }
    265   }
    266 #endif
    267 
    268   ThreadRegistry *tr = ctx->thread_registry;
    269   OnStartedArgs args = { thr, stk_addr, stk_size, tls_addr, tls_size };
    270   tr->StartThread(tid, os_id, &args);
    271 
    272   tr->Lock();
    273   thr->tctx = (ThreadContext*)tr->GetThreadLocked(tid);
    274   tr->Unlock();
    275 
    276 #ifndef SANITIZER_GO
    277   if (ctx->after_multithreaded_fork) {
    278     thr->ignore_interceptors++;
    279     ThreadIgnoreBegin(thr, 0);
    280     ThreadIgnoreSyncBegin(thr, 0);
    281   }
    282 #endif
    283 }
    284 
    285 void ThreadFinish(ThreadState *thr) {
    286   ThreadCheckIgnore(thr);
    287   StatInc(thr, StatThreadFinish);
    288   if (thr->stk_addr && thr->stk_size)
    289     DontNeedShadowFor(thr->stk_addr, thr->stk_size);
    290   if (thr->tls_addr && thr->tls_size)
    291     DontNeedShadowFor(thr->tls_addr, thr->tls_size);
    292   thr->is_dead = true;
    293   ctx->thread_registry->FinishThread(thr->tid);
    294 }
    295 
    296 static bool FindThreadByUid(ThreadContextBase *tctx, void *arg) {
    297   uptr uid = (uptr)arg;
    298   if (tctx->user_id == uid && tctx->status != ThreadStatusInvalid) {
    299     tctx->user_id = 0;
    300     return true;
    301   }
    302   return false;
    303 }
    304 
    305 int ThreadTid(ThreadState *thr, uptr pc, uptr uid) {
    306   int res = ctx->thread_registry->FindThread(FindThreadByUid, (void*)uid);
    307   DPrintf("#%d: ThreadTid uid=%zu tid=%d\n", thr->tid, uid, res);
    308   return res;
    309 }
    310 
    311 void ThreadJoin(ThreadState *thr, uptr pc, int tid) {
    312   CHECK_GT(tid, 0);
    313   CHECK_LT(tid, kMaxTid);
    314   DPrintf("#%d: ThreadJoin tid=%d\n", thr->tid, tid);
    315   ctx->thread_registry->JoinThread(tid, thr);
    316 }
    317 
    318 void ThreadDetach(ThreadState *thr, uptr pc, int tid) {
    319   CHECK_GT(tid, 0);
    320   CHECK_LT(tid, kMaxTid);
    321   ctx->thread_registry->DetachThread(tid, thr);
    322 }
    323 
    324 void ThreadSetName(ThreadState *thr, const char *name) {
    325   ctx->thread_registry->SetThreadName(thr->tid, name);
    326 }
    327 
    328 void MemoryAccessRange(ThreadState *thr, uptr pc, uptr addr,
    329                        uptr size, bool is_write) {
    330   if (size == 0)
    331     return;
    332 
    333   u64 *shadow_mem = (u64*)MemToShadow(addr);
    334   DPrintf2("#%d: MemoryAccessRange: @%p %p size=%d is_write=%d\n",
    335       thr->tid, (void*)pc, (void*)addr,
    336       (int)size, is_write);
    337 
    338 #if SANITIZER_DEBUG
    339   if (!IsAppMem(addr)) {
    340     Printf("Access to non app mem %zx\n", addr);
    341     DCHECK(IsAppMem(addr));
    342   }
    343   if (!IsAppMem(addr + size - 1)) {
    344     Printf("Access to non app mem %zx\n", addr + size - 1);
    345     DCHECK(IsAppMem(addr + size - 1));
    346   }
    347   if (!IsShadowMem((uptr)shadow_mem)) {
    348     Printf("Bad shadow addr %p (%zx)\n", shadow_mem, addr);
    349     DCHECK(IsShadowMem((uptr)shadow_mem));
    350   }
    351   if (!IsShadowMem((uptr)(shadow_mem + size * kShadowCnt / 8 - 1))) {
    352     Printf("Bad shadow addr %p (%zx)\n",
    353                shadow_mem + size * kShadowCnt / 8 - 1, addr + size - 1);
    354     DCHECK(IsShadowMem((uptr)(shadow_mem + size * kShadowCnt / 8 - 1)));
    355   }
    356 #endif
    357 
    358   StatInc(thr, StatMopRange);
    359 
    360   if (*shadow_mem == kShadowRodata) {
    361     // Access to .rodata section, no races here.
    362     // Measurements show that it can be 10-20% of all memory accesses.
    363     StatInc(thr, StatMopRangeRodata);
    364     return;
    365   }
    366 
    367   FastState fast_state = thr->fast_state;
    368   if (fast_state.GetIgnoreBit())
    369     return;
    370 
    371   fast_state.IncrementEpoch();
    372   thr->fast_state = fast_state;
    373   TraceAddEvent(thr, fast_state, EventTypeMop, pc);
    374 
    375   bool unaligned = (addr % kShadowCell) != 0;
    376 
    377   // Handle unaligned beginning, if any.
    378   for (; addr % kShadowCell && size; addr++, size--) {
    379     int const kAccessSizeLog = 0;
    380     Shadow cur(fast_state);
    381     cur.SetWrite(is_write);
    382     cur.SetAddr0AndSizeLog(addr & (kShadowCell - 1), kAccessSizeLog);
    383     MemoryAccessImpl(thr, addr, kAccessSizeLog, is_write, false,
    384         shadow_mem, cur);
    385   }
    386   if (unaligned)
    387     shadow_mem += kShadowCnt;
    388   // Handle middle part, if any.
    389   for (; size >= kShadowCell; addr += kShadowCell, size -= kShadowCell) {
    390     int const kAccessSizeLog = 3;
    391     Shadow cur(fast_state);
    392     cur.SetWrite(is_write);
    393     cur.SetAddr0AndSizeLog(0, kAccessSizeLog);
    394     MemoryAccessImpl(thr, addr, kAccessSizeLog, is_write, false,
    395         shadow_mem, cur);
    396     shadow_mem += kShadowCnt;
    397   }
    398   // Handle ending, if any.
    399   for (; size; addr++, size--) {
    400     int const kAccessSizeLog = 0;
    401     Shadow cur(fast_state);
    402     cur.SetWrite(is_write);
    403     cur.SetAddr0AndSizeLog(addr & (kShadowCell - 1), kAccessSizeLog);
    404     MemoryAccessImpl(thr, addr, kAccessSizeLog, is_write, false,
    405         shadow_mem, cur);
    406   }
    407 }
    408 
    409 }  // namespace __tsan
    410