lib/sanitizer_common/sanitizer_deadlock_detector1.cc

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