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(<->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(<->dd, m->id)) return; // We already have all edges. 108 SpinMutexLock lk(&mtx); 109 MutexEnsureID(lt, m); 110 if (dd.isHeld(<->dd, m->id)) 111 return; // FIXME: allow this only for recursive locks. 112 if (dd.onLockBefore(<->dd, m->id)) { 113 // Actually add this edge now so that we have all the stack traces. 114 dd.addEdges(<->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(<->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 = <->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(<->dd, m->id, stk)) 154 return; 155 if (dd.onLockFast(<->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(<->dd, m->id)); 162 if (!trylock) 163 dd.addEdges(<->dd, m->id, stk ? stk : cb->Unwind(), cb->UniqueTid()); 164 dd.onLockAfter(<->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 == 1 190
