| //===-- sanitizer_deadlock_detector1.cpp ----------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Deadlock detector implementation based on NxN adjacency bit matrix. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "sanitizer_deadlock_detector_interface.h" |
| #include "sanitizer_deadlock_detector.h" |
| #include "sanitizer_allocator_internal.h" |
| #include "sanitizer_placement_new.h" |
| #include "sanitizer_mutex.h" |
| |
| #if SANITIZER_DEADLOCK_DETECTOR_VERSION == 1 |
| |
| namespace __sanitizer { |
| |
| typedef TwoLevelBitVector<> DDBV; // DeadlockDetector's bit vector. |
| |
| struct DDPhysicalThread { |
| }; |
| |
| struct DDLogicalThread { |
| u64 ctx; |
| DeadlockDetectorTLS<DDBV> dd; |
| DDReport rep; |
| bool report_pending; |
| }; |
| |
| struct DD final : public DDetector { |
| SpinMutex mtx; |
| DeadlockDetector<DDBV> dd; |
| DDFlags flags; |
| |
| explicit DD(const DDFlags *flags); |
| |
| DDPhysicalThread *CreatePhysicalThread() override; |
| void DestroyPhysicalThread(DDPhysicalThread *pt) override; |
| |
| DDLogicalThread *CreateLogicalThread(u64 ctx) override; |
| void DestroyLogicalThread(DDLogicalThread *lt) override; |
| |
| void MutexInit(DDCallback *cb, DDMutex *m) override; |
| void MutexBeforeLock(DDCallback *cb, DDMutex *m, bool wlock) override; |
| void MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock, |
| bool trylock) override; |
| void MutexBeforeUnlock(DDCallback *cb, DDMutex *m, bool wlock) override; |
| void MutexDestroy(DDCallback *cb, DDMutex *m) override; |
| |
| DDReport *GetReport(DDCallback *cb) override; |
| |
| void MutexEnsureID(DDLogicalThread *lt, DDMutex *m); |
| void ReportDeadlock(DDCallback *cb, DDMutex *m); |
| }; |
| |
| DDetector *DDetector::Create(const DDFlags *flags) { |
| (void)flags; |
| void *mem = MmapOrDie(sizeof(DD), "deadlock detector"); |
| return new(mem) DD(flags); |
| } |
| |
| DD::DD(const DDFlags *flags) |
| : flags(*flags) { |
| dd.clear(); |
| } |
| |
| DDPhysicalThread* DD::CreatePhysicalThread() { |
| return nullptr; |
| } |
| |
| void DD::DestroyPhysicalThread(DDPhysicalThread *pt) { |
| } |
| |
| DDLogicalThread* DD::CreateLogicalThread(u64 ctx) { |
| DDLogicalThread *lt = (DDLogicalThread*)InternalAlloc(sizeof(*lt)); |
| lt->ctx = ctx; |
| lt->dd.clear(); |
| lt->report_pending = false; |
| return lt; |
| } |
| |
| void DD::DestroyLogicalThread(DDLogicalThread *lt) { |
| lt->~DDLogicalThread(); |
| InternalFree(lt); |
| } |
| |
| void DD::MutexInit(DDCallback *cb, DDMutex *m) { |
| m->id = 0; |
| m->stk = cb->Unwind(); |
| } |
| |
| void DD::MutexEnsureID(DDLogicalThread *lt, DDMutex *m) { |
| if (!dd.nodeBelongsToCurrentEpoch(m->id)) |
| m->id = dd.newNode(reinterpret_cast<uptr>(m)); |
| dd.ensureCurrentEpoch(<->dd); |
| } |
| |
| void DD::MutexBeforeLock(DDCallback *cb, |
| DDMutex *m, bool wlock) { |
| DDLogicalThread *lt = cb->lt; |
| if (lt->dd.empty()) return; // This will be the first lock held by lt. |
| if (dd.hasAllEdges(<->dd, m->id)) return; // We already have all edges. |
| SpinMutexLock lk(&mtx); |
| MutexEnsureID(lt, m); |
| if (dd.isHeld(<->dd, m->id)) |
| return; // FIXME: allow this only for recursive locks. |
| if (dd.onLockBefore(<->dd, m->id)) { |
| // Actually add this edge now so that we have all the stack traces. |
| dd.addEdges(<->dd, m->id, cb->Unwind(), cb->UniqueTid()); |
| ReportDeadlock(cb, m); |
| } |
| } |
| |
| void DD::ReportDeadlock(DDCallback *cb, DDMutex *m) { |
| DDLogicalThread *lt = cb->lt; |
| uptr path[20]; |
| uptr len = dd.findPathToLock(<->dd, m->id, path, ARRAY_SIZE(path)); |
| if (len == 0U) { |
| // A cycle of 20+ locks? Well, that's a bit odd... |
| Printf("WARNING: too long mutex cycle found\n"); |
| return; |
| } |
| CHECK_EQ(m->id, path[0]); |
| lt->report_pending = true; |
| len = Min<uptr>(len, DDReport::kMaxLoopSize); |
| DDReport *rep = <->rep; |
| rep->n = len; |
| for (uptr i = 0; i < len; i++) { |
| uptr from = path[i]; |
| uptr to = path[(i + 1) % len]; |
| DDMutex *m0 = (DDMutex*)dd.getData(from); |
| DDMutex *m1 = (DDMutex*)dd.getData(to); |
| |
| u32 stk_from = -1U, stk_to = -1U; |
| int unique_tid = 0; |
| dd.findEdge(from, to, &stk_from, &stk_to, &unique_tid); |
| // Printf("Edge: %zd=>%zd: %u/%u T%d\n", from, to, stk_from, stk_to, |
| // unique_tid); |
| rep->loop[i].thr_ctx = unique_tid; |
| rep->loop[i].mtx_ctx0 = m0->ctx; |
| rep->loop[i].mtx_ctx1 = m1->ctx; |
| rep->loop[i].stk[0] = stk_to; |
| rep->loop[i].stk[1] = stk_from; |
| } |
| } |
| |
| void DD::MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock, bool trylock) { |
| DDLogicalThread *lt = cb->lt; |
| u32 stk = 0; |
| if (flags.second_deadlock_stack) |
| stk = cb->Unwind(); |
| // Printf("T%p MutexLock: %zx stk %u\n", lt, m->id, stk); |
| if (dd.onFirstLock(<->dd, m->id, stk)) |
| return; |
| if (dd.onLockFast(<->dd, m->id, stk)) |
| return; |
| |
| SpinMutexLock lk(&mtx); |
| MutexEnsureID(lt, m); |
| if (wlock) // Only a recursive rlock may be held. |
| CHECK(!dd.isHeld(<->dd, m->id)); |
| if (!trylock) |
| dd.addEdges(<->dd, m->id, stk ? stk : cb->Unwind(), cb->UniqueTid()); |
| dd.onLockAfter(<->dd, m->id, stk); |
| } |
| |
| void DD::MutexBeforeUnlock(DDCallback *cb, DDMutex *m, bool wlock) { |
| // Printf("T%p MutexUnLock: %zx\n", cb->lt, m->id); |
| dd.onUnlock(&cb->lt->dd, m->id); |
| } |
| |
| void DD::MutexDestroy(DDCallback *cb, |
| DDMutex *m) { |
| if (!m->id) return; |
| SpinMutexLock lk(&mtx); |
| if (dd.nodeBelongsToCurrentEpoch(m->id)) |
| dd.removeNode(m->id); |
| m->id = 0; |
| } |
| |
| DDReport *DD::GetReport(DDCallback *cb) { |
| if (!cb->lt->report_pending) |
| return nullptr; |
| cb->lt->report_pending = false; |
| return &cb->lt->rep; |
| } |
| |
| } // namespace __sanitizer |
| #endif // #if SANITIZER_DEADLOCK_DETECTOR_VERSION == 1 |