zig/lib/tsan/sanitizer_common/sanitizer_deadlock_detector2.cpp
2020-12-24 01:18:47 -07:00

424 lines
11 KiB
C++

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