libsanitizer/sanitizer_common/sanitizer_deadlock_detector1.cc

   1 //===-- sanitizer_deadlock_detector1.cc -----------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // Deadlock detector implementation based on NxN adjacency bit matrix.
   9 //
  10 //===----------------------------------------------------------------------===//
  11
  12 #include "sanitizer_deadlock_detector_interface.h"
  13 #include "sanitizer_deadlock_detector.h"
  14 #include "sanitizer_allocator_internal.h"
  15 #include "sanitizer_placement_new.h"
  16 #include "sanitizer_mutex.h"
  17
  18 #if SANITIZER_DEADLOCK_DETECTOR_VERSION == 1
  19
  20 namespace __sanitizer {
  21
  22 typedef TwoLevelBitVector<> DDBV;  // DeadlockDetector's bit vector.
  23
  24 struct DDPhysicalThread {
  25 };
  26
  27 struct DDLogicalThread {
  28   u64 ctx;
  29   DeadlockDetectorTLS<DDBV> dd;
  30   DDReport rep;
  31   bool report_pending;
  32 };
  33
  34 struct DD : public DDetector {
  35   SpinMutex mtx;
  36   DeadlockDetector<DDBV> dd;
  37   DDFlags flags;
  38
  39   explicit DD(const DDFlags *flags);
  40
  41   DDPhysicalThread *CreatePhysicalThread() override;
  42   void DestroyPhysicalThread(DDPhysicalThread *pt) override;
  43
  44   DDLogicalThread *CreateLogicalThread(u64 ctx) override;
  45   void DestroyLogicalThread(DDLogicalThread *lt) override;
  46
  47   void MutexInit(DDCallback *cb, DDMutex *m) override;
  48   void MutexBeforeLock(DDCallback *cb, DDMutex *m, bool wlock) override;
  49   void MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock,
  50                       bool trylock) override;
  51   void MutexBeforeUnlock(DDCallback *cb, DDMutex *m, bool wlock) override;
  52   void MutexDestroy(DDCallback *cb, DDMutex *m) override;
  53
  54   DDReport *GetReport(DDCallback *cb) override;
  55
  56   void MutexEnsureID(DDLogicalThread *lt, DDMutex *m);
  57   void ReportDeadlock(DDCallback *cb, DDMutex *m);
  58 };
  59
  60 DDetector *DDetector::Create(const DDFlags *flags) {
  61   (void)flags;
  62   void *mem = MmapOrDie(sizeof(DD), "deadlock detector");
  63   return new(mem) DD(flags);
  64 }
  65
  66 DD::DD(const DDFlags *flags)
  67     : flags(*flags) {
  68   dd.clear();
  69 }
  70
  71 DDPhysicalThread* DD::CreatePhysicalThread() {
  72   return nullptr;
  73 }
  74
  75 void DD::DestroyPhysicalThread(DDPhysicalThread *pt) {
  76 }
  77
  78 DDLogicalThread* DD::CreateLogicalThread(u64 ctx) {
  79   DDLogicalThread *lt = (DDLogicalThread*)InternalAlloc(sizeof(*lt));
  80   lt->ctx = ctx;
  81   lt->dd.clear();
  82   lt->report_pending = false;
  83   return lt;
  84 }
  85
  86 void DD::DestroyLogicalThread(DDLogicalThread *lt) {
  87   lt->~DDLogicalThread();
  88   InternalFree(lt);
  89 }
  90
  91 void DD::MutexInit(DDCallback *cb, DDMutex *m) {
  92   m->id = 0;
  93   m->stk = cb->Unwind();
  94 }
  95
  96 void DD::MutexEnsureID(DDLogicalThread *lt, DDMutex *m) {
  97   if (!dd.nodeBelongsToCurrentEpoch(m->id))
  98     m->id = dd.newNode(reinterpret_cast<uptr>(m));
  99   dd.ensureCurrentEpoch(&lt->dd);
 100 }
 101
 102 void DD::MutexBeforeLock(DDCallback *cb,
 103     DDMutex *m, bool wlock) {
 104   DDLogicalThread *lt = cb->lt;
 105   if (lt->dd.empty()) return;  // This will be the first lock held by lt.
 106   if (dd.hasAllEdges(&lt->dd, m->id)) return;  // We already have all edges.
 107   SpinMutexLock lk(&mtx);
 108   MutexEnsureID(lt, m);
 109   if (dd.isHeld(&lt->dd, m->id))
 110     return;  // FIXME: allow this only for recursive locks.
 111   if (dd.onLockBefore(&lt->dd, m->id)) {
 112     // Actually add this edge now so that we have all the stack traces.
 113     dd.addEdges(&lt->dd, m->id, cb->Unwind(), cb->UniqueTid());
 114     ReportDeadlock(cb, m);
 115   }
 116 }
 117
 118 void DD::ReportDeadlock(DDCallback *cb, DDMutex *m) {
 119   DDLogicalThread *lt = cb->lt;
 120   uptr path[20];
 121   uptr len = dd.findPathToLock(&lt->dd, m->id, path, ARRAY_SIZE(path));
 122   if (len == 0U) {
 123     // A cycle of 20+ locks? Well, that's a bit odd...
 124     Printf("WARNING: too long mutex cycle found\n");
 125     return;
 126   }
 127   CHECK_EQ(m->id, path[0]);
 128   lt->report_pending = true;
 129   len = Min<uptr>(len, DDReport::kMaxLoopSize);
 130   DDReport *rep = &lt->rep;
 131   rep->n = len;
 132   for (uptr i = 0; i < len; i++) {
 133     uptr from = path[i];
 134     uptr to = path[(i + 1) % len];
 135     DDMutex *m0 = (DDMutex*)dd.getData(from);
 136     DDMutex *m1 = (DDMutex*)dd.getData(to);
 137
 138     u32 stk_from = -1U, stk_to = -1U;
 139     int unique_tid = 0;
 140     dd.findEdge(from, to, &stk_from, &stk_to, &unique_tid);
 141     // Printf("Edge: %zd=>%zd: %u/%u T%d\n", from, to, stk_from, stk_to,
 142     //    unique_tid);
 143     rep->loop[i].thr_ctx = unique_tid;
 144     rep->loop[i].mtx_ctx0 = m0->ctx;
 145     rep->loop[i].mtx_ctx1 = m1->ctx;
 146     rep->loop[i].stk[0] = stk_to;
 147     rep->loop[i].stk[1] = stk_from;
 148   }
 149 }
 150
 151 void DD::MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock, bool trylock) {
 152   DDLogicalThread *lt = cb->lt;
 153   u32 stk = 0;
 154   if (flags.second_deadlock_stack)
 155     stk = cb->Unwind();
 156   // Printf("T%p MutexLock:   %zx stk %u\n", lt, m->id, stk);
 157   if (dd.onFirstLock(&lt->dd, m->id, stk))
 158     return;
 159   if (dd.onLockFast(&lt->dd, m->id, stk))
 160     return;
 161
 162   SpinMutexLock lk(&mtx);
 163   MutexEnsureID(lt, m);
 164   if (wlock)  // Only a recursive rlock may be held.
 165     CHECK(!dd.isHeld(&lt->dd, m->id));
 166   if (!trylock)
 167     dd.addEdges(&lt->dd, m->id, stk ? stk : cb->Unwind(), cb->UniqueTid());
 168   dd.onLockAfter(&lt->dd, m->id, stk);
 169 }
 170
 171 void DD::MutexBeforeUnlock(DDCallback *cb, DDMutex *m, bool wlock) {
 172   // Printf("T%p MutexUnLock: %zx\n", cb->lt, m->id);
 173   dd.onUnlock(&cb->lt->dd, m->id);
 174 }
 175
 176 void DD::MutexDestroy(DDCallback *cb,
 177     DDMutex *m) {
 178   if (!m->id) return;
 179   SpinMutexLock lk(&mtx);
 180   if (dd.nodeBelongsToCurrentEpoch(m->id))
 181     dd.removeNode(m->id);
 182   m->id = 0;
 183 }
 184
 185 DDReport *DD::GetReport(DDCallback *cb) {
 186   if (!cb->lt->report_pending)
 187     return nullptr;
 188   cb->lt->report_pending = false;
 189   return &cb->lt->rep;
 190 }
 191
 192 } // namespace __sanitizer
 193 #endif // #if SANITIZER_DEADLOCK_DETECTOR_VERSION == 1