src/compiler-rt/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() override;
  44   void DestroyPhysicalThread(DDPhysicalThread *pt) override;
  45
  46   DDLogicalThread *CreateLogicalThread(u64 ctx) override;
  47   void DestroyLogicalThread(DDLogicalThread *lt) override;
  48
  49   void MutexInit(DDCallback *cb, DDMutex *m) override;
  50   void MutexBeforeLock(DDCallback *cb, DDMutex *m, bool wlock) override;
  51   void MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock,
  52                       bool trylock) override;
  53   void MutexBeforeUnlock(DDCallback *cb, DDMutex *m, bool wlock) override;
  54   void MutexDestroy(DDCallback *cb, DDMutex *m) override;
  55
  56   DDReport *GetReport(DDCallback *cb) override;
  57
  58   void MutexEnsureID(DDLogicalThread *lt, DDMutex *m);
  59   void ReportDeadlock(DDCallback *cb, DDMutex *m);
  60 };
  61
  62 DDetector *DDetector::Create(const DDFlags *flags) {
  63   (void)flags;
  64   void *mem = MmapOrDie(sizeof(DD), "deadlock detector");
  65   return new(mem) DD(flags);
  66 }
  67
  68 DD::DD(const DDFlags *flags)
  69     : flags(*flags) {
  70   dd.clear();
  71 }
  72
  73 DDPhysicalThread* DD::CreatePhysicalThread() {
  74   return nullptr;
  75 }
  76
  77 void DD::DestroyPhysicalThread(DDPhysicalThread *pt) {
  78 }
  79
  80 DDLogicalThread* DD::CreateLogicalThread(u64 ctx) {
  81   DDLogicalThread *lt = (DDLogicalThread*)InternalAlloc(sizeof(*lt));
  82   lt->ctx = ctx;
  83   lt->dd.clear();
  84   lt->report_pending = false;
  85   return lt;
  86 }
  87
  88 void DD::DestroyLogicalThread(DDLogicalThread *lt) {
  89   lt->~DDLogicalThread();
  90   InternalFree(lt);
  91 }
  92
  93 void DD::MutexInit(DDCallback *cb, DDMutex *m) {
  94   m->id = 0;
  95   m->stk = cb->Unwind();
  96 }
  97
  98 void DD::MutexEnsureID(DDLogicalThread *lt, DDMutex *m) {
  99   if (!dd.nodeBelongsToCurrentEpoch(m->id))
 100     m->id = dd.newNode(reinterpret_cast<uptr>(m));
 101   dd.ensureCurrentEpoch(&lt->dd);
 102 }
 103
 104 void DD::MutexBeforeLock(DDCallback *cb,
 105     DDMutex *m, bool wlock) {
 106   DDLogicalThread *lt = cb->lt;
 107   if (lt->dd.empty()) return;  // This will be the first lock held by lt.
 108   if (dd.hasAllEdges(&lt->dd, m->id)) return;  // We already have all edges.
 109   SpinMutexLock lk(&mtx);
 110   MutexEnsureID(lt, m);
 111   if (dd.isHeld(&lt->dd, m->id))
 112     return;  // FIXME: allow this only for recursive locks.
 113   if (dd.onLockBefore(&lt->dd, m->id)) {
 114     // Actually add this edge now so that we have all the stack traces.
 115     dd.addEdges(&lt->dd, m->id, cb->Unwind(), cb->UniqueTid());
 116     ReportDeadlock(cb, m);
 117   }
 118 }
 119
 120 void DD::ReportDeadlock(DDCallback *cb, DDMutex *m) {
 121   DDLogicalThread *lt = cb->lt;
 122   uptr path[20];
 123   uptr len = dd.findPathToLock(&lt->dd, m->id, path, ARRAY_SIZE(path));
 124   if (len == 0U) {
 125     // A cycle of 20+ locks? Well, that's a bit odd...
 126     Printf("WARNING: too long mutex cycle found\n");
 127     return;
 128   }
 129   CHECK_EQ(m->id, path[0]);
 130   lt->report_pending = true;
 131   len = Min<uptr>(len, DDReport::kMaxLoopSize);
 132   DDReport *rep = &lt->rep;
 133   rep->n = len;
 134   for (uptr i = 0; i < len; i++) {
 135     uptr from = path[i];
 136     uptr to = path[(i + 1) % len];
 137     DDMutex *m0 = (DDMutex*)dd.getData(from);
 138     DDMutex *m1 = (DDMutex*)dd.getData(to);
 139
 140     u32 stk_from = -1U, stk_to = -1U;
 141     int unique_tid = 0;
 142     dd.findEdge(from, to, &stk_from, &stk_to, &unique_tid);
 143     // Printf("Edge: %zd=>%zd: %u/%u T%d\n", from, to, stk_from, stk_to,
 144     //    unique_tid);
 145     rep->loop[i].thr_ctx = unique_tid;
 146     rep->loop[i].mtx_ctx0 = m0->ctx;
 147     rep->loop[i].mtx_ctx1 = m1->ctx;
 148     rep->loop[i].stk[0] = stk_to;
 149     rep->loop[i].stk[1] = stk_from;
 150   }
 151 }
 152
 153 void DD::MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock, bool trylock) {
 154   DDLogicalThread *lt = cb->lt;
 155   u32 stk = 0;
 156   if (flags.second_deadlock_stack)
 157     stk = cb->Unwind();
 158   // Printf("T%p MutexLock:   %zx stk %u\n", lt, m->id, stk);
 159   if (dd.onFirstLock(&lt->dd, m->id, stk))
 160     return;
 161   if (dd.onLockFast(&lt->dd, m->id, stk))
 162     return;
 163
 164   SpinMutexLock lk(&mtx);
 165   MutexEnsureID(lt, m);
 166   if (wlock)  // Only a recursive rlock may be held.
 167     CHECK(!dd.isHeld(&lt->dd, m->id));
 168   if (!trylock)
 169     dd.addEdges(&lt->dd, m->id, stk ? stk : cb->Unwind(), cb->UniqueTid());
 170   dd.onLockAfter(&lt->dd, m->id, stk);
 171 }
 172
 173 void DD::MutexBeforeUnlock(DDCallback *cb, DDMutex *m, bool wlock) {
 174   // Printf("T%p MutexUnLock: %zx\n", cb->lt, m->id);
 175   dd.onUnlock(&cb->lt->dd, m->id);
 176 }
 177
 178 void DD::MutexDestroy(DDCallback *cb,
 179     DDMutex *m) {
 180   if (!m->id) return;
 181   SpinMutexLock lk(&mtx);
 182   if (dd.nodeBelongsToCurrentEpoch(m->id))
 183     dd.removeNode(m->id);
 184   m->id = 0;
 185 }
 186
 187 DDReport *DD::GetReport(DDCallback *cb) {
 188   if (!cb->lt->report_pending)
 189     return nullptr;
 190   cb->lt->report_pending = false;
 191   return &cb->lt->rep;
 192 }
 193
 194 } // namespace __sanitizer
 195 #endif // #if SANITIZER_DEADLOCK_DETECTOR_VERSION == 1