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