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      1 //===-- dd_rtl.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 #include "dd_rtl.h"
     11 #include "sanitizer_common/sanitizer_common.h"
     12 #include "sanitizer_common/sanitizer_placement_new.h"
     13 #include "sanitizer_common/sanitizer_flags.h"
     14 #include "sanitizer_common/sanitizer_stacktrace.h"
     15 #include "sanitizer_common/sanitizer_stackdepot.h"
     16 
     17 namespace __dsan {
     18 
     19 static Context *ctx;
     20 
     21 static u32 CurrentStackTrace(Thread *thr, uptr skip) {
     22   StackTrace trace;
     23   thr->ignore_interceptors = true;
     24   trace.Unwind(1000, 0, 0, 0, 0, 0, false);
     25   thr->ignore_interceptors = false;
     26   if (trace.size <= skip)
     27     return 0;
     28   return StackDepotPut(trace.trace + skip, trace.size - skip);
     29 }
     30 
     31 static void PrintStackTrace(Thread *thr, u32 stk) {
     32   uptr size = 0;
     33   const uptr *trace = StackDepotGet(stk, &size);
     34   thr->ignore_interceptors = true;
     35   StackTrace::PrintStack(trace, size);
     36   thr->ignore_interceptors = false;
     37 }
     38 
     39 static void ReportDeadlock(Thread *thr, DDReport *rep) {
     40   if (rep == 0)
     41     return;
     42   BlockingMutexLock lock(&ctx->report_mutex);
     43   Printf("==============================\n");
     44   Printf("WARNING: lock-order-inversion (potential deadlock)\n");
     45   for (int i = 0; i < rep->n; i++) {
     46     Printf("Thread %d locks mutex %llu while holding mutex %llu:\n",
     47       rep->loop[i].thr_ctx, rep->loop[i].mtx_ctx1, rep->loop[i].mtx_ctx0);
     48     PrintStackTrace(thr, rep->loop[i].stk[1]);
     49     if (rep->loop[i].stk[0]) {
     50       Printf("Mutex %llu was acquired here:\n",
     51         rep->loop[i].mtx_ctx0);
     52       PrintStackTrace(thr, rep->loop[i].stk[0]);
     53     }
     54   }
     55   Printf("==============================\n");
     56 }
     57 
     58 Callback::Callback(Thread *thr)
     59     : thr(thr) {
     60   lt = thr->dd_lt;
     61   pt = thr->dd_pt;
     62 }
     63 
     64 u32 Callback::Unwind() {
     65   return CurrentStackTrace(thr, 3);
     66 }
     67 
     68 void InitializeFlags(Flags *f, const char *env) {
     69   internal_memset(f, 0, sizeof(*f));
     70 
     71   // Default values.
     72   f->second_deadlock_stack = false;
     73 
     74   SetCommonFlagsDefaults(f);
     75   // Override some common flags defaults.
     76   f->allow_addr2line = true;
     77 
     78   // Override from command line.
     79   ParseFlag(env, &f->second_deadlock_stack, "second_deadlock_stack", "");
     80   ParseCommonFlagsFromString(f, env);
     81 
     82   // Copy back to common flags.
     83   *common_flags() = *f;
     84 }
     85 
     86 void Initialize() {
     87   static u64 ctx_mem[sizeof(Context) / sizeof(u64) + 1];
     88   ctx = new(ctx_mem) Context();
     89 
     90   InitializeInterceptors();
     91   InitializeFlags(flags(), GetEnv("DSAN_OPTIONS"));
     92   common_flags()->symbolize = true;
     93   ctx->dd = DDetector::Create(flags());
     94 }
     95 
     96 void ThreadInit(Thread *thr) {
     97   static atomic_uintptr_t id_gen;
     98   uptr id = atomic_fetch_add(&id_gen, 1, memory_order_relaxed);
     99   thr->dd_pt = ctx->dd->CreatePhysicalThread();
    100   thr->dd_lt = ctx->dd->CreateLogicalThread(id);
    101 }
    102 
    103 void ThreadDestroy(Thread *thr) {
    104   ctx->dd->DestroyPhysicalThread(thr->dd_pt);
    105   ctx->dd->DestroyLogicalThread(thr->dd_lt);
    106 }
    107 
    108 void MutexBeforeLock(Thread *thr, uptr m, bool writelock) {
    109   if (thr->ignore_interceptors)
    110     return;
    111   Callback cb(thr);
    112   {
    113     MutexHashMap::Handle h(&ctx->mutex_map, m);
    114     if (h.created())
    115       ctx->dd->MutexInit(&cb, &h->dd);
    116     ctx->dd->MutexBeforeLock(&cb, &h->dd, writelock);
    117   }
    118   ReportDeadlock(thr, ctx->dd->GetReport(&cb));
    119 }
    120 
    121 void MutexAfterLock(Thread *thr, uptr m, bool writelock, bool trylock) {
    122   if (thr->ignore_interceptors)
    123     return;
    124   Callback cb(thr);
    125   {
    126     MutexHashMap::Handle h(&ctx->mutex_map, m);
    127     if (h.created())
    128       ctx->dd->MutexInit(&cb, &h->dd);
    129     ctx->dd->MutexAfterLock(&cb, &h->dd, writelock, trylock);
    130   }
    131   ReportDeadlock(thr, ctx->dd->GetReport(&cb));
    132 }
    133 
    134 void MutexBeforeUnlock(Thread *thr, uptr m, bool writelock) {
    135   if (thr->ignore_interceptors)
    136     return;
    137   Callback cb(thr);
    138   {
    139     MutexHashMap::Handle h(&ctx->mutex_map, m);
    140     ctx->dd->MutexBeforeUnlock(&cb, &h->dd, writelock);
    141   }
    142   ReportDeadlock(thr, ctx->dd->GetReport(&cb));
    143 }
    144 
    145 void MutexDestroy(Thread *thr, uptr m) {
    146   if (thr->ignore_interceptors)
    147     return;
    148   Callback cb(thr);
    149   MutexHashMap::Handle h(&ctx->mutex_map, m, true);
    150   if (!h.exists())
    151     return;
    152   ctx->dd->MutexDestroy(&cb, &h->dd);
    153 }
    154 
    155 }  // namespace __dsan
    156