1 //===-- sanitizer_deadlock_detector1.cc -----------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Deadlock detector implementation based on NxN adjacency bit matrix.
12 //===----------------------------------------------------------------------===//
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"
20 #if SANITIZER_DEADLOCK_DETECTOR_VERSION == 1
22 namespace __sanitizer {
24 typedef TwoLevelBitVector<> DDBV; // DeadlockDetector's bit vector.
26 struct DDPhysicalThread {
29 struct DDLogicalThread {
31 DeadlockDetectorTLS<DDBV> dd;
36 struct DD : public DDetector {
38 DeadlockDetector<DDBV> dd;
41 explicit DD(const DDFlags *flags);
43 DDPhysicalThread* CreatePhysicalThread();
44 void DestroyPhysicalThread(DDPhysicalThread *pt);
46 DDLogicalThread* CreateLogicalThread(u64 ctx);
47 void DestroyLogicalThread(DDLogicalThread *lt);
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);
55 DDReport *GetReport(DDCallback *cb);
57 void MutexEnsureID(DDLogicalThread *lt, DDMutex *m);
58 void ReportDeadlock(DDCallback *cb, DDMutex *m);
61 DDetector *DDetector::Create(const DDFlags *flags) {
63 void *mem = MmapOrDie(sizeof(DD), "deadlock detector");
64 return new(mem) DD(flags);
67 DD::DD(const DDFlags *flags)
72 DDPhysicalThread* DD::CreatePhysicalThread() {
76 void DD::DestroyPhysicalThread(DDPhysicalThread *pt) {
79 DDLogicalThread* DD::CreateLogicalThread(u64 ctx) {
80 DDLogicalThread *lt = (DDLogicalThread*)InternalAlloc(sizeof(*lt));
83 lt->report_pending = false;
87 void DD::DestroyLogicalThread(DDLogicalThread *lt) {
88 lt->~DDLogicalThread();
92 void DD::MutexInit(DDCallback *cb, DDMutex *m) {
94 m->stk = cb->Unwind();
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);
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);
119 void DD::ReportDeadlock(DDCallback *cb, DDMutex *m) {
120 DDLogicalThread *lt = cb->lt;
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;
128 for (uptr i = 0; i < len; i++) {
130 uptr to = path[(i + 1) % len];
131 DDMutex *m0 = (DDMutex*)dd.getData(from);
132 DDMutex *m1 = (DDMutex*)dd.getData(to);
134 u32 stk_from = -1U, stk_to = -1U;
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,
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;
147 void DD::MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock, bool trylock) {
148 DDLogicalThread *lt = cb->lt;
150 if (flags.second_deadlock_stack)
152 // Printf("T%p MutexLock: %zx stk %u\n", lt, m->id, stk);
153 if (dd.onFirstLock(<->dd, m->id, stk))
155 if (dd.onLockFast(<->dd, m->id, stk))
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));
163 dd.addEdges(<->dd, m->id, stk ? stk : cb->Unwind(), cb->UniqueTid());
164 dd.onLockAfter(<->dd, m->id, stk);
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);
172 void DD::MutexDestroy(DDCallback *cb,
175 SpinMutexLock lk(&mtx);
176 if (dd.nodeBelongsToCurrentEpoch(m->id))
177 dd.removeNode(m->id);
181 DDReport *DD::GetReport(DDCallback *cb) {
182 if (!cb->lt->report_pending)
184 cb->lt->report_pending = false;
188 } // namespace __sanitizer
189 #endif // #if SANITIZER_DEADLOCK_DETECTOR_VERSION == 1