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();
  42   void DestroyPhysicalThread(DDPhysicalThread *pt);
  43
  44   DDLogicalThread* CreateLogicalThread(u64 ctx);
  45   void DestroyLogicalThread(DDLogicalThread *lt);
  46
  47   void MutexInit(DDCallback *cb, DDMutex *m);
  48   void MutexBeforeLock(DDCallback *cb, DDMutex *m, bool wlock);
  49   void MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock, bool trylock);
  50   void MutexBeforeUnlock(DDCallback *cb, DDMutex *m, bool wlock);
  51   void MutexDestroy(DDCallback *cb, DDMutex *m);
  52
  53   DDReport *GetReport(DDCallback *cb);
  54
  55   void MutexEnsureID(DDLogicalThread *lt, DDMutex *m);
  56   void ReportDeadlock(DDCallback *cb, DDMutex *m);
  57 };
  58
  59 DDetector *DDetector::Create(const DDFlags *flags) {
  60   (void)flags;
  61   void *mem = MmapOrDie(sizeof(DD), "deadlock detector");
  62   return new(mem) DD(flags);
  63 }
  64
  65 DD::DD(const DDFlags *flags)
  66     : flags(*flags) {
  67   dd.clear();
  68 }
  69
  70 DDPhysicalThread* DD::CreatePhysicalThread() {
  71   return 0;
  72 }
  73
  74 void DD::DestroyPhysicalThread(DDPhysicalThread *pt) {
  75 }
  76
  77 DDLogicalThread* DD::CreateLogicalThread(u64 ctx) {
  78   DDLogicalThread *lt = (DDLogicalThread*)InternalAlloc(sizeof(*lt));
  79   lt->ctx = ctx;
  80   lt->dd.clear();
  81   lt->report_pending = false;
  82   return lt;
  83 }
  84
  85 void DD::DestroyLogicalThread(DDLogicalThread *lt) {
  86   lt->~DDLogicalThread();
  87   InternalFree(lt);
  88 }
  89
  90 void DD::MutexInit(DDCallback *cb, DDMutex *m) {
  91   m->id = 0;
  92   m->stk = cb->Unwind();
  93 }
  94
  95 void DD::MutexEnsureID(DDLogicalThread *lt, DDMutex *m) {
  96   if (!dd.nodeBelongsToCurrentEpoch(m->id))
  97     m->id = dd.newNode(reinterpret_cast<uptr>(m));
  98   dd.ensureCurrentEpoch(&lt->dd);
  99 }
 100
 101 void DD::MutexBeforeLock(DDCallback *cb,
 102     DDMutex *m, bool wlock) {
 103   DDLogicalThread *lt = cb->lt;
 104   if (lt->dd.empty()) return;  // This will be the first lock held by lt.
 105   if (dd.hasAllEdges(&lt->dd, m->id)) return;  // We already have all edges.
 106   SpinMutexLock lk(&mtx);
 107   MutexEnsureID(lt, m);
 108   if (dd.isHeld(&lt->dd, m->id))
 109     return;  // FIXME: allow this only for recursive locks.
 110   if (dd.onLockBefore(&lt->dd, m->id)) {
 111     // Actually add this edge now so that we have all the stack traces.
 112     dd.addEdges(&lt->dd, m->id, cb->Unwind(), cb->UniqueTid());
 113     ReportDeadlock(cb, m);
 114   }
 115 }
 116
 117 void DD::ReportDeadlock(DDCallback *cb, DDMutex *m) {
 118   DDLogicalThread *lt = cb->lt;
 119   uptr path[10];
 120   uptr len = dd.findPathToLock(&lt->dd, m->id, path, ARRAY_SIZE(path));
 121   CHECK_GT(len, 0U);  // Hm.. cycle of 10 locks? I'd like to see that.
 122   CHECK_EQ(m->id, path[0]);
 123   lt->report_pending = true;
 124   DDReport *rep = &lt->rep;
 125   rep->n = len;
 126   for (uptr i = 0; i < len; i++) {
 127     uptr from = path[i];
 128     uptr to = path[(i + 1) % len];
 129     DDMutex *m0 = (DDMutex*)dd.getData(from);
 130     DDMutex *m1 = (DDMutex*)dd.getData(to);
 131
 132     u32 stk_from = -1U, stk_to = -1U;
 133     int unique_tid = 0;
 134     dd.findEdge(from, to, &stk_from, &stk_to, &unique_tid);
 135     // Printf("Edge: %zd=>%zd: %u/%u T%d\n", from, to, stk_from, stk_to,
 136     //    unique_tid);
 137     rep->loop[i].thr_ctx = unique_tid;
 138     rep->loop[i].mtx_ctx0 = m0->ctx;
 139     rep->loop[i].mtx_ctx1 = m1->ctx;
 140     rep->loop[i].stk[0] = stk_to;
 141     rep->loop[i].stk[1] = stk_from;
 142   }
 143 }
 144
 145 void DD::MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock, bool trylock) {
 146   DDLogicalThread *lt = cb->lt;
 147   u32 stk = 0;
 148   if (flags.second_deadlock_stack)
 149     stk = cb->Unwind();
 150   // Printf("T%p MutexLock:   %zx stk %u\n", lt, m->id, stk);
 151   if (dd.onFirstLock(&lt->dd, m->id, stk))
 152     return;
 153   if (dd.onLockFast(&lt->dd, m->id, stk))
 154     return;
 155
 156   SpinMutexLock lk(&mtx);
 157   MutexEnsureID(lt, m);
 158   if (wlock)  // Only a recursive rlock may be held.
 159     CHECK(!dd.isHeld(&lt->dd, m->id));
 160   if (!trylock)
 161     dd.addEdges(&lt->dd, m->id, stk ? stk : cb->Unwind(), cb->UniqueTid());
 162   dd.onLockAfter(&lt->dd, m->id, stk);
 163 }
 164
 165 void DD::MutexBeforeUnlock(DDCallback *cb, DDMutex *m, bool wlock) {
 166   // Printf("T%p MutexUnLock: %zx\n", cb->lt, m->id);
 167   dd.onUnlock(&cb->lt->dd, m->id);
 168 }
 169
 170 void DD::MutexDestroy(DDCallback *cb,
 171     DDMutex *m) {
 172   if (!m->id) return;
 173   SpinMutexLock lk(&mtx);
 174   if (dd.nodeBelongsToCurrentEpoch(m->id))
 175     dd.removeNode(m->id);
 176   m->id = 0;
 177 }
 178
 179 DDReport *DD::GetReport(DDCallback *cb) {
 180   if (!cb->lt->report_pending)
 181     return 0;
 182   cb->lt->report_pending = false;
 183   return &cb->lt->rep;
 184 }
 185
 186 }  // namespace __sanitizer
 187 #endif  // #if SANITIZER_DEADLOCK_DETECTOR_VERSION == 1