195 lines · cpp
1//===-- sanitizer_deadlock_detector1.cpp ----------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// Deadlock detector implementation based on NxN adjacency bit matrix.10//11//===----------------------------------------------------------------------===//12 13#include "sanitizer_deadlock_detector_interface.h"14#include "sanitizer_deadlock_detector.h"15#include "sanitizer_allocator_internal.h"16#include "sanitizer_placement_new.h"17#include "sanitizer_mutex.h"18 19#if SANITIZER_DEADLOCK_DETECTOR_VERSION == 120 21namespace __sanitizer {22 23typedef TwoLevelBitVector<> DDBV; // DeadlockDetector's bit vector.24 25struct DDPhysicalThread {26};27 28struct DDLogicalThread {29 u64 ctx;30 DeadlockDetectorTLS<DDBV> dd;31 DDReport rep;32 bool report_pending;33};34 35struct DD final : public DDetector {36 SpinMutex mtx;37 DeadlockDetector<DDBV> dd;38 DDFlags flags;39 40 explicit DD(const DDFlags *flags);41 42 DDPhysicalThread *CreatePhysicalThread() override;43 void DestroyPhysicalThread(DDPhysicalThread *pt) override;44 45 DDLogicalThread *CreateLogicalThread(u64 ctx) override;46 void DestroyLogicalThread(DDLogicalThread *lt) override;47 48 void MutexInit(DDCallback *cb, DDMutex *m) override;49 void MutexBeforeLock(DDCallback *cb, DDMutex *m, bool wlock) override;50 void MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock,51 bool trylock) override;52 void MutexBeforeUnlock(DDCallback *cb, DDMutex *m, bool wlock) override;53 void MutexDestroy(DDCallback *cb, DDMutex *m) override;54 55 DDReport *GetReport(DDCallback *cb) override;56 57 void MutexEnsureID(DDLogicalThread *lt, DDMutex *m);58 void ReportDeadlock(DDCallback *cb, DDMutex *m);59};60 61DDetector *DDetector::Create(const DDFlags *flags) {62 (void)flags;63 void *mem = MmapOrDie(sizeof(DD), "deadlock detector");64 return new(mem) DD(flags);65}66 67DD::DD(const DDFlags *flags)68 : flags(*flags) {69 dd.clear();70}71 72DDPhysicalThread* DD::CreatePhysicalThread() {73 return nullptr;74}75 76void DD::DestroyPhysicalThread(DDPhysicalThread *pt) {77}78 79DDLogicalThread* 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 87void DD::DestroyLogicalThread(DDLogicalThread *lt) {88 lt->~DDLogicalThread();89 InternalFree(lt);90}91 92void DD::MutexInit(DDCallback *cb, DDMutex *m) {93 m->id = 0;94 m->stk = cb->Unwind();95}96 97void 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 103void 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 119void DD::ReportDeadlock(DDCallback *cb, DDMutex *m) {120 DDLogicalThread *lt = cb->lt;121 uptr path[20];122 uptr len = dd.findPathToLock(<->dd, m->id, path, ARRAY_SIZE(path));123 if (len == 0U) {124 // A cycle of 20+ locks? Well, that's a bit odd...125 Printf("WARNING: too long mutex cycle found\n");126 return;127 }128 CHECK_EQ(m->id, path[0]);129 lt->report_pending = true;130 len = Min<uptr>(len, DDReport::kMaxLoopSize);131 DDReport *rep = <->rep;132 rep->n = len;133 for (uptr i = 0; i < len; i++) {134 uptr from = path[i];135 uptr to = path[(i + 1) % len];136 DDMutex *m0 = (DDMutex*)dd.getData(from);137 DDMutex *m1 = (DDMutex*)dd.getData(to);138 139 u32 stk_from = 0, stk_to = 0;140 int unique_tid = 0;141 dd.findEdge(from, to, &stk_from, &stk_to, &unique_tid);142 // Printf("Edge: %zd=>%zd: %u/%u T%d\n", from, to, stk_from, stk_to,143 // unique_tid);144 rep->loop[i].thr_ctx = unique_tid;145 rep->loop[i].mtx_ctx0 = m0->ctx;146 rep->loop[i].mtx_ctx1 = m1->ctx;147 rep->loop[i].stk[0] = stk_to;148 rep->loop[i].stk[1] = stk_from;149 }150}151 152void DD::MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock, bool trylock) {153 DDLogicalThread *lt = cb->lt;154 u32 stk = 0;155 if (flags.second_deadlock_stack)156 stk = cb->Unwind();157 // Printf("T%p MutexLock: %zx stk %u\n", lt, m->id, stk);158 if (dd.onFirstLock(<->dd, m->id, stk))159 return;160 if (dd.onLockFast(<->dd, m->id, stk))161 return;162 163 SpinMutexLock lk(&mtx);164 MutexEnsureID(lt, m);165 if (wlock) // Only a recursive rlock may be held.166 CHECK(!dd.isHeld(<->dd, m->id));167 if (!trylock)168 dd.addEdges(<->dd, m->id, stk ? stk : cb->Unwind(), cb->UniqueTid());169 dd.onLockAfter(<->dd, m->id, stk);170}171 172void DD::MutexBeforeUnlock(DDCallback *cb, DDMutex *m, bool wlock) {173 // Printf("T%p MutexUnLock: %zx\n", cb->lt, m->id);174 dd.onUnlock(&cb->lt->dd, m->id);175}176 177void DD::MutexDestroy(DDCallback *cb,178 DDMutex *m) {179 if (!m->id) return;180 SpinMutexLock lk(&mtx);181 if (dd.nodeBelongsToCurrentEpoch(m->id))182 dd.removeNode(m->id);183 m->id = 0;184}185 186DDReport *DD::GetReport(DDCallback *cb) {187 if (!cb->lt->report_pending)188 return nullptr;189 cb->lt->report_pending = false;190 return &cb->lt->rep;191}192 193} // namespace __sanitizer194#endif // #if SANITIZER_DEADLOCK_DETECTOR_VERSION == 1195