forked from OSchip/llvm-project
424 lines
11 KiB
C++
424 lines
11 KiB
C++
//===-- sanitizer_deadlock_detector2.cc -----------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// Deadlock detector implementation based on adjacency lists.
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//
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//===----------------------------------------------------------------------===//
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#include "sanitizer_deadlock_detector_interface.h"
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#include "sanitizer_common.h"
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#include "sanitizer_allocator_internal.h"
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#include "sanitizer_placement_new.h"
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#include "sanitizer_mutex.h"
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#if SANITIZER_DEADLOCK_DETECTOR_VERSION == 2
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namespace __sanitizer {
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const int kMaxNesting = 64;
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const u32 kNoId = -1;
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const u32 kEndId = -2;
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const int kMaxLink = 8;
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const int kL1Size = 1024;
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const int kL2Size = 1024;
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const int kMaxMutex = kL1Size * kL2Size;
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struct Id {
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u32 id;
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u32 seq;
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explicit Id(u32 id = 0, u32 seq = 0)
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: id(id)
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, seq(seq) {
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}
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};
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struct Link {
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u32 id;
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u32 seq;
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u32 tid;
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u32 stk0;
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u32 stk1;
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explicit Link(u32 id = 0, u32 seq = 0, u32 tid = 0, u32 s0 = 0, u32 s1 = 0)
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: id(id)
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, seq(seq)
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, tid(tid)
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, stk0(s0)
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, stk1(s1) {
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}
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};
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struct DDPhysicalThread {
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DDReport rep;
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bool report_pending;
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bool visited[kMaxMutex];
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Link pending[kMaxMutex];
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Link path[kMaxMutex];
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};
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struct ThreadMutex {
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u32 id;
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u32 stk;
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};
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struct DDLogicalThread {
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u64 ctx;
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ThreadMutex locked[kMaxNesting];
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int nlocked;
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};
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struct Mutex {
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StaticSpinMutex mtx;
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u32 seq;
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int nlink;
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Link link[kMaxLink];
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};
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struct DD : public DDetector {
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explicit DD(const DDFlags *flags);
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DDPhysicalThread* CreatePhysicalThread();
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void DestroyPhysicalThread(DDPhysicalThread *pt);
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DDLogicalThread* CreateLogicalThread(u64 ctx);
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void DestroyLogicalThread(DDLogicalThread *lt);
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void MutexInit(DDCallback *cb, DDMutex *m);
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void MutexBeforeLock(DDCallback *cb, DDMutex *m, bool wlock);
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void MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock,
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bool trylock);
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void MutexBeforeUnlock(DDCallback *cb, DDMutex *m, bool wlock);
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void MutexDestroy(DDCallback *cb, DDMutex *m);
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DDReport *GetReport(DDCallback *cb);
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void CycleCheck(DDPhysicalThread *pt, DDLogicalThread *lt, DDMutex *mtx);
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void Report(DDPhysicalThread *pt, DDLogicalThread *lt, int npath);
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u32 allocateId(DDCallback *cb);
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Mutex *getMutex(u32 id);
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u32 getMutexId(Mutex *m);
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DDFlags flags;
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Mutex* mutex[kL1Size];
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SpinMutex mtx;
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InternalMmapVector<u32> free_id;
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int id_gen = 0;
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};
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DDetector *DDetector::Create(const DDFlags *flags) {
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(void)flags;
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void *mem = MmapOrDie(sizeof(DD), "deadlock detector");
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return new(mem) DD(flags);
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}
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DD::DD(const DDFlags *flags) : flags(*flags) { free_id.reserve(1024); }
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DDPhysicalThread* DD::CreatePhysicalThread() {
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DDPhysicalThread *pt = (DDPhysicalThread*)MmapOrDie(sizeof(DDPhysicalThread),
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"deadlock detector (physical thread)");
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return pt;
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}
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void DD::DestroyPhysicalThread(DDPhysicalThread *pt) {
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pt->~DDPhysicalThread();
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UnmapOrDie(pt, sizeof(DDPhysicalThread));
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}
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DDLogicalThread* DD::CreateLogicalThread(u64 ctx) {
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DDLogicalThread *lt = (DDLogicalThread*)InternalAlloc(
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sizeof(DDLogicalThread));
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lt->ctx = ctx;
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lt->nlocked = 0;
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return lt;
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}
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void DD::DestroyLogicalThread(DDLogicalThread *lt) {
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lt->~DDLogicalThread();
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InternalFree(lt);
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}
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void DD::MutexInit(DDCallback *cb, DDMutex *m) {
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VPrintf(2, "#%llu: DD::MutexInit(%p)\n", cb->lt->ctx, m);
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m->id = kNoId;
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m->recursion = 0;
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atomic_store(&m->owner, 0, memory_order_relaxed);
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}
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Mutex *DD::getMutex(u32 id) {
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return &mutex[id / kL2Size][id % kL2Size];
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}
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u32 DD::getMutexId(Mutex *m) {
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for (int i = 0; i < kL1Size; i++) {
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Mutex *tab = mutex[i];
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if (tab == 0)
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break;
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if (m >= tab && m < tab + kL2Size)
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return i * kL2Size + (m - tab);
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}
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return -1;
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}
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u32 DD::allocateId(DDCallback *cb) {
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u32 id = -1;
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SpinMutexLock l(&mtx);
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if (free_id.size() > 0) {
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id = free_id.back();
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free_id.pop_back();
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} else {
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CHECK_LT(id_gen, kMaxMutex);
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if ((id_gen % kL2Size) == 0) {
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mutex[id_gen / kL2Size] = (Mutex*)MmapOrDie(kL2Size * sizeof(Mutex),
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"deadlock detector (mutex table)");
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}
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id = id_gen++;
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}
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CHECK_LE(id, kMaxMutex);
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VPrintf(3, "#%llu: DD::allocateId assign id %d\n", cb->lt->ctx, id);
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return id;
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}
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void DD::MutexBeforeLock(DDCallback *cb, DDMutex *m, bool wlock) {
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VPrintf(2, "#%llu: DD::MutexBeforeLock(%p, wlock=%d) nlocked=%d\n",
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cb->lt->ctx, m, wlock, cb->lt->nlocked);
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DDPhysicalThread *pt = cb->pt;
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DDLogicalThread *lt = cb->lt;
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uptr owner = atomic_load(&m->owner, memory_order_relaxed);
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if (owner == (uptr)cb->lt) {
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VPrintf(3, "#%llu: DD::MutexBeforeLock recursive\n",
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cb->lt->ctx);
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return;
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}
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CHECK_LE(lt->nlocked, kMaxNesting);
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// FIXME(dvyukov): don't allocate id if lt->nlocked == 0?
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if (m->id == kNoId)
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m->id = allocateId(cb);
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ThreadMutex *tm = <->locked[lt->nlocked++];
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tm->id = m->id;
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if (flags.second_deadlock_stack)
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tm->stk = cb->Unwind();
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if (lt->nlocked == 1) {
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VPrintf(3, "#%llu: DD::MutexBeforeLock first mutex\n",
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cb->lt->ctx);
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return;
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}
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bool added = false;
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Mutex *mtx = getMutex(m->id);
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for (int i = 0; i < lt->nlocked - 1; i++) {
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u32 id1 = lt->locked[i].id;
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u32 stk1 = lt->locked[i].stk;
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Mutex *mtx1 = getMutex(id1);
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SpinMutexLock l(&mtx1->mtx);
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if (mtx1->nlink == kMaxLink) {
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// FIXME(dvyukov): check stale links
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continue;
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}
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int li = 0;
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for (; li < mtx1->nlink; li++) {
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Link *link = &mtx1->link[li];
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if (link->id == m->id) {
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if (link->seq != mtx->seq) {
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link->seq = mtx->seq;
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link->tid = lt->ctx;
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link->stk0 = stk1;
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link->stk1 = cb->Unwind();
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added = true;
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VPrintf(3, "#%llu: DD::MutexBeforeLock added %d->%d link\n",
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cb->lt->ctx, getMutexId(mtx1), m->id);
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}
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break;
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}
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}
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if (li == mtx1->nlink) {
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// FIXME(dvyukov): check stale links
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Link *link = &mtx1->link[mtx1->nlink++];
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link->id = m->id;
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link->seq = mtx->seq;
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link->tid = lt->ctx;
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link->stk0 = stk1;
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link->stk1 = cb->Unwind();
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added = true;
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VPrintf(3, "#%llu: DD::MutexBeforeLock added %d->%d link\n",
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cb->lt->ctx, getMutexId(mtx1), m->id);
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}
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}
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if (!added || mtx->nlink == 0) {
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VPrintf(3, "#%llu: DD::MutexBeforeLock don't check\n",
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cb->lt->ctx);
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return;
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}
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CycleCheck(pt, lt, m);
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}
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void DD::MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock,
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bool trylock) {
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VPrintf(2, "#%llu: DD::MutexAfterLock(%p, wlock=%d, try=%d) nlocked=%d\n",
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cb->lt->ctx, m, wlock, trylock, cb->lt->nlocked);
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DDLogicalThread *lt = cb->lt;
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uptr owner = atomic_load(&m->owner, memory_order_relaxed);
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if (owner == (uptr)cb->lt) {
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VPrintf(3, "#%llu: DD::MutexAfterLock recursive\n", cb->lt->ctx);
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CHECK(wlock);
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m->recursion++;
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return;
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}
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CHECK_EQ(owner, 0);
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if (wlock) {
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VPrintf(3, "#%llu: DD::MutexAfterLock set owner\n", cb->lt->ctx);
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CHECK_EQ(m->recursion, 0);
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m->recursion = 1;
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atomic_store(&m->owner, (uptr)cb->lt, memory_order_relaxed);
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}
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if (!trylock)
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return;
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CHECK_LE(lt->nlocked, kMaxNesting);
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if (m->id == kNoId)
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m->id = allocateId(cb);
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ThreadMutex *tm = <->locked[lt->nlocked++];
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tm->id = m->id;
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if (flags.second_deadlock_stack)
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tm->stk = cb->Unwind();
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}
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void DD::MutexBeforeUnlock(DDCallback *cb, DDMutex *m, bool wlock) {
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VPrintf(2, "#%llu: DD::MutexBeforeUnlock(%p, wlock=%d) nlocked=%d\n",
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cb->lt->ctx, m, wlock, cb->lt->nlocked);
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DDLogicalThread *lt = cb->lt;
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uptr owner = atomic_load(&m->owner, memory_order_relaxed);
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if (owner == (uptr)cb->lt) {
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VPrintf(3, "#%llu: DD::MutexBeforeUnlock recursive\n", cb->lt->ctx);
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if (--m->recursion > 0)
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return;
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VPrintf(3, "#%llu: DD::MutexBeforeUnlock reset owner\n", cb->lt->ctx);
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atomic_store(&m->owner, 0, memory_order_relaxed);
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}
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CHECK_NE(m->id, kNoId);
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int last = lt->nlocked - 1;
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for (int i = last; i >= 0; i--) {
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if (cb->lt->locked[i].id == m->id) {
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lt->locked[i] = lt->locked[last];
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lt->nlocked--;
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break;
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}
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}
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}
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void DD::MutexDestroy(DDCallback *cb, DDMutex *m) {
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VPrintf(2, "#%llu: DD::MutexDestroy(%p)\n",
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cb->lt->ctx, m);
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DDLogicalThread *lt = cb->lt;
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if (m->id == kNoId)
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return;
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// Remove the mutex from lt->locked if there.
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int last = lt->nlocked - 1;
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for (int i = last; i >= 0; i--) {
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if (lt->locked[i].id == m->id) {
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lt->locked[i] = lt->locked[last];
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lt->nlocked--;
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break;
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}
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}
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// Clear and invalidate the mutex descriptor.
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{
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Mutex *mtx = getMutex(m->id);
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SpinMutexLock l(&mtx->mtx);
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mtx->seq++;
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mtx->nlink = 0;
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}
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// Return id to cache.
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{
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SpinMutexLock l(&mtx);
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free_id.push_back(m->id);
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}
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}
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void DD::CycleCheck(DDPhysicalThread *pt, DDLogicalThread *lt,
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DDMutex *m) {
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internal_memset(pt->visited, 0, sizeof(pt->visited));
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int npath = 0;
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int npending = 0;
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{
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Mutex *mtx = getMutex(m->id);
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SpinMutexLock l(&mtx->mtx);
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for (int li = 0; li < mtx->nlink; li++)
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pt->pending[npending++] = mtx->link[li];
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}
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while (npending > 0) {
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Link link = pt->pending[--npending];
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if (link.id == kEndId) {
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npath--;
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continue;
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}
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if (pt->visited[link.id])
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continue;
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Mutex *mtx1 = getMutex(link.id);
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SpinMutexLock l(&mtx1->mtx);
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if (mtx1->seq != link.seq)
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continue;
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pt->visited[link.id] = true;
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if (mtx1->nlink == 0)
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continue;
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pt->path[npath++] = link;
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pt->pending[npending++] = Link(kEndId);
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if (link.id == m->id)
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return Report(pt, lt, npath); // Bingo!
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for (int li = 0; li < mtx1->nlink; li++) {
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Link *link1 = &mtx1->link[li];
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// Mutex *mtx2 = getMutex(link->id);
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// FIXME(dvyukov): fast seq check
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// FIXME(dvyukov): fast nlink != 0 check
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// FIXME(dvyukov): fast pending check?
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// FIXME(dvyukov): npending can be larger than kMaxMutex
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pt->pending[npending++] = *link1;
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}
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}
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}
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void DD::Report(DDPhysicalThread *pt, DDLogicalThread *lt, int npath) {
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DDReport *rep = &pt->rep;
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rep->n = npath;
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for (int i = 0; i < npath; i++) {
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Link *link = &pt->path[i];
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Link *link0 = &pt->path[i ? i - 1 : npath - 1];
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rep->loop[i].thr_ctx = link->tid;
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rep->loop[i].mtx_ctx0 = link0->id;
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rep->loop[i].mtx_ctx1 = link->id;
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rep->loop[i].stk[0] = flags.second_deadlock_stack ? link->stk0 : 0;
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rep->loop[i].stk[1] = link->stk1;
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}
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pt->report_pending = true;
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}
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DDReport *DD::GetReport(DDCallback *cb) {
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if (!cb->pt->report_pending)
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return 0;
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cb->pt->report_pending = false;
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return &cb->pt->rep;
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}
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} // namespace __sanitizer
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#endif // #if SANITIZER_DEADLOCK_DETECTOR_VERSION == 2
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