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-rw-r--r--absl/synchronization/mutex.cc148
1 files changed, 92 insertions, 56 deletions
diff --git a/absl/synchronization/mutex.cc b/absl/synchronization/mutex.cc
index 9f8d6cd7..07f220f5 100644
--- a/absl/synchronization/mutex.cc
+++ b/absl/synchronization/mutex.cc
@@ -4,7 +4,7 @@
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
-// http://www.apache.org/licenses/LICENSE-2.0
+// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
@@ -71,7 +71,7 @@ ABSL_ATTRIBUTE_WEAK void AbslInternalMutexYield() { std::this_thread::yield(); }
} // extern "C"
namespace absl {
-inline namespace lts_2018_12_18 {
+inline namespace lts_2019_08_08 {
namespace {
@@ -119,6 +119,10 @@ ABSL_CONST_INIT absl::base_internal::AtomicHook<
} // namespace
+static inline bool EvalConditionAnnotated(const Condition *cond, Mutex *mu,
+ bool locking, bool trylock,
+ bool read_lock);
+
void RegisterMutexProfiler(void (*fn)(int64_t wait_timestamp)) {
submit_profile_data.Store(fn);
}
@@ -151,7 +155,7 @@ static int Delay(int32_t c, DelayMode mode) {
if (c < limit) {
c++; // spin
} else {
- ABSL_TSAN_MUTEX_PRE_DIVERT(0, 0);
+ ABSL_TSAN_MUTEX_PRE_DIVERT(nullptr, 0);
if (c == limit) { // yield once
AbslInternalMutexYield();
c++;
@@ -159,7 +163,7 @@ static int Delay(int32_t c, DelayMode mode) {
absl::SleepFor(absl::Microseconds(10));
c = 0;
}
- ABSL_TSAN_MUTEX_POST_DIVERT(0, 0);
+ ABSL_TSAN_MUTEX_POST_DIVERT(nullptr, 0);
}
return (c);
}
@@ -234,15 +238,14 @@ enum { // Mutex and CondVar events passed as "ev" to PostSynchEvent
SYNCH_EV_SIGNALALL,
};
-enum { // Event flags
- SYNCH_F_R = 0x01, // reader event
- SYNCH_F_LCK = 0x02, // PostSynchEvent called with mutex held
- SYNCH_F_ACQ = 0x04, // event is an acquire
+enum { // Event flags
+ SYNCH_F_R = 0x01, // reader event
+ SYNCH_F_LCK = 0x02, // PostSynchEvent called with mutex held
+ SYNCH_F_TRY = 0x04, // TryLock or ReaderTryLock
+ SYNCH_F_UNLOCK = 0x08, // Unlock or ReaderUnlock
SYNCH_F_LCK_W = SYNCH_F_LCK,
SYNCH_F_LCK_R = SYNCH_F_LCK | SYNCH_F_R,
- SYNCH_F_ACQ_W = SYNCH_F_ACQ,
- SYNCH_F_ACQ_R = SYNCH_F_ACQ | SYNCH_F_R,
};
} // anonymous namespace
@@ -251,21 +254,22 @@ static const struct {
int flags;
const char *msg;
} event_properties[] = {
- { SYNCH_F_LCK_W|SYNCH_F_ACQ_W, "TryLock succeeded " },
- { 0, "TryLock failed " },
- { SYNCH_F_LCK_R|SYNCH_F_ACQ_R, "ReaderTryLock succeeded " },
- { 0, "ReaderTryLock failed " },
- { SYNCH_F_ACQ_W, "Lock blocking " },
- { SYNCH_F_LCK_W, "Lock returning " },
- { SYNCH_F_ACQ_R, "ReaderLock blocking " },
- { SYNCH_F_LCK_R, "ReaderLock returning " },
- { SYNCH_F_LCK_W, "Unlock " },
- { SYNCH_F_LCK_R, "ReaderUnlock " },
- { 0, "Wait on " },
- { 0, "Wait unblocked " },
- { 0, "Signal on " },
- { 0, "SignalAll on " },
+ {SYNCH_F_LCK_W | SYNCH_F_TRY, "TryLock succeeded "},
+ {0, "TryLock failed "},
+ {SYNCH_F_LCK_R | SYNCH_F_TRY, "ReaderTryLock succeeded "},
+ {0, "ReaderTryLock failed "},
+ {0, "Lock blocking "},
+ {SYNCH_F_LCK_W, "Lock returning "},
+ {0, "ReaderLock blocking "},
+ {SYNCH_F_LCK_R, "ReaderLock returning "},
+ {SYNCH_F_LCK_W | SYNCH_F_UNLOCK, "Unlock "},
+ {SYNCH_F_LCK_R | SYNCH_F_UNLOCK, "ReaderUnlock "},
+ {0, "Wait on "},
+ {0, "Wait unblocked "},
+ {0, "Signal on "},
+ {0, "SignalAll on "},
};
+
static absl::base_internal::SpinLock synch_event_mu(
absl::base_internal::kLinkerInitialized);
// protects synch_event
@@ -415,9 +419,26 @@ static void PostSynchEvent(void *obj, int ev) {
ABSL_RAW_LOG(INFO, "%s%p %s %s", event_properties[ev].msg, obj,
(e == nullptr ? "" : e->name), buffer);
}
- if ((event_properties[ev].flags & SYNCH_F_LCK) != 0 && e != nullptr &&
- e->invariant != nullptr) {
- (*e->invariant)(e->arg);
+ const int flags = event_properties[ev].flags;
+ if ((flags & SYNCH_F_LCK) != 0 && e != nullptr && e->invariant != nullptr) {
+ // Calling the invariant as is causes problems under ThreadSanitizer.
+ // We are currently inside of Mutex Lock/Unlock and are ignoring all
+ // memory accesses and synchronization. If the invariant transitively
+ // synchronizes something else and we ignore the synchronization, we will
+ // get false positive race reports later.
+ // Reuse EvalConditionAnnotated to properly call into user code.
+ struct local {
+ static bool pred(SynchEvent *ev) {
+ (*ev->invariant)(ev->arg);
+ return false;
+ }
+ };
+ Condition cond(&local::pred, e);
+ Mutex *mu = static_cast<Mutex *>(obj);
+ const bool locking = (flags & SYNCH_F_UNLOCK) == 0;
+ const bool trylock = (flags & SYNCH_F_TRY) != 0;
+ const bool read_lock = (flags & SYNCH_F_R) != 0;
+ EvalConditionAnnotated(&cond, mu, locking, trylock, read_lock);
}
UnrefSynchEvent(e);
}
@@ -881,11 +902,15 @@ static PerThreadSynch *Enqueue(PerThreadSynch *head,
// base_internal::CycleClock::Now() is 0.5%.
int policy;
struct sched_param param;
- pthread_getschedparam(pthread_self(), &policy, &param);
- s->priority = param.sched_priority;
- s->next_priority_read_cycles =
- now_cycles +
- static_cast<int64_t>(base_internal::CycleClock::Frequency());
+ const int err = pthread_getschedparam(pthread_self(), &policy, &param);
+ if (err != 0) {
+ ABSL_RAW_LOG(ERROR, "pthread_getschedparam failed: %d", err);
+ } else {
+ s->priority = param.sched_priority;
+ s->next_priority_read_cycles =
+ now_cycles +
+ static_cast<int64_t>(base_internal::CycleClock::Frequency());
+ }
}
if (s->priority > head->priority) { // s's priority is above head's
// try to put s in priority-fifo order, or failing that at the front.
@@ -1080,7 +1105,7 @@ void Mutex::TryRemove(PerThreadSynch *s) {
// if the wait extends past the absolute time specified, even if "s" is still
// on the mutex queue. In this case, remove "s" from the queue and return
// true, otherwise return false.
-void Mutex::Block(PerThreadSynch *s) {
+ABSL_XRAY_LOG_ARGS(1) void Mutex::Block(PerThreadSynch *s) {
while (s->state.load(std::memory_order_acquire) == PerThreadSynch::kQueued) {
if (!DecrementSynchSem(this, s, s->waitp->timeout)) {
// After a timeout, we go into a spin loop until we remove ourselves
@@ -1553,7 +1578,7 @@ bool Mutex::AwaitCommon(const Condition &cond, KernelTimeout t) {
ABSL_TSAN_MUTEX_PRE_LOCK(this, TsanFlags(how));
this->LockSlowLoop(&waitp, flags);
bool res = waitp.cond != nullptr || // => cond known true from LockSlowLoop
- cond.Eval();
+ EvalConditionAnnotated(&cond, this, true, false, how == kShared);
ABSL_TSAN_MUTEX_POST_LOCK(this, TsanFlags(how), 0);
return res;
}
@@ -1731,12 +1756,17 @@ void Mutex::LockSlow(MuHow how, const Condition *cond, int flags) {
// Compute cond->Eval() and tell race detectors that we do it under mutex mu.
static inline bool EvalConditionAnnotated(const Condition *cond, Mutex *mu,
- bool locking, Mutex::MuHow how) {
+ bool locking, bool trylock,
+ bool read_lock) {
// Delicate annotation dance.
// We are currently inside of read/write lock/unlock operation.
// All memory accesses are ignored inside of mutex operations + for unlock
// operation tsan considers that we've already released the mutex.
bool res = false;
+#ifdef THREAD_SANITIZER
+ const int flags = read_lock ? __tsan_mutex_read_lock : 0;
+ const int tryflags = flags | (trylock ? __tsan_mutex_try_lock : 0);
+#endif
if (locking) {
// For lock we pretend that we have finished the operation,
// evaluate the predicate, then unlock the mutex and start locking it again
@@ -1744,24 +1774,26 @@ static inline bool EvalConditionAnnotated(const Condition *cond, Mutex *mu,
// Note: we can't simply do POST_LOCK, Eval, PRE_LOCK, because then tsan
// will think the lock acquisition is recursive which will trigger
// deadlock detector.
- ABSL_TSAN_MUTEX_POST_LOCK(mu, TsanFlags(how), 0);
+ ABSL_TSAN_MUTEX_POST_LOCK(mu, tryflags, 0);
res = cond->Eval();
- ABSL_TSAN_MUTEX_PRE_UNLOCK(mu, TsanFlags(how));
- ABSL_TSAN_MUTEX_POST_UNLOCK(mu, TsanFlags(how));
- ABSL_TSAN_MUTEX_PRE_LOCK(mu, TsanFlags(how));
+ // There is no "try" version of Unlock, so use flags instead of tryflags.
+ ABSL_TSAN_MUTEX_PRE_UNLOCK(mu, flags);
+ ABSL_TSAN_MUTEX_POST_UNLOCK(mu, flags);
+ ABSL_TSAN_MUTEX_PRE_LOCK(mu, tryflags);
} else {
// Similarly, for unlock we pretend that we have unlocked the mutex,
// lock the mutex, evaluate the predicate, and start unlocking it again
// to match the annotation at the end of outer unlock operation.
- ABSL_TSAN_MUTEX_POST_UNLOCK(mu, TsanFlags(how));
- ABSL_TSAN_MUTEX_PRE_LOCK(mu, TsanFlags(how));
- ABSL_TSAN_MUTEX_POST_LOCK(mu, TsanFlags(how), 0);
+ ABSL_TSAN_MUTEX_POST_UNLOCK(mu, flags);
+ ABSL_TSAN_MUTEX_PRE_LOCK(mu, flags);
+ ABSL_TSAN_MUTEX_POST_LOCK(mu, flags, 0);
res = cond->Eval();
- ABSL_TSAN_MUTEX_PRE_UNLOCK(mu, TsanFlags(how));
+ ABSL_TSAN_MUTEX_PRE_UNLOCK(mu, flags);
}
// Prevent unused param warnings in non-TSAN builds.
static_cast<void>(mu);
- static_cast<void>(how);
+ static_cast<void>(trylock);
+ static_cast<void>(read_lock);
return res;
}
@@ -1807,7 +1839,8 @@ bool Mutex::LockSlowWithDeadline(MuHow how, const Condition *cond,
v, (how->fast_or | (v & zap_desig_waker[flags & kMuHasBlocked])) +
how->fast_add,
std::memory_order_acquire, std::memory_order_relaxed)) {
- if (cond == nullptr || EvalConditionAnnotated(cond, this, true, how)) {
+ if (cond == nullptr ||
+ EvalConditionAnnotated(cond, this, true, false, how == kShared)) {
return true;
}
unlock = true;
@@ -1825,7 +1858,8 @@ bool Mutex::LockSlowWithDeadline(MuHow how, const Condition *cond,
}
this->LockSlowLoop(&waitp, flags);
return waitp.cond != nullptr || // => cond known true from LockSlowLoop
- cond == nullptr || EvalConditionAnnotated(cond, this, true, how);
+ cond == nullptr ||
+ EvalConditionAnnotated(cond, this, true, false, how == kShared);
}
// RAW_CHECK_FMT() takes a condition, a printf-style format string, and
@@ -1842,7 +1876,7 @@ static void CheckForMutexCorruption(intptr_t v, const char* label) {
// Test for either of two situations that should not occur in v:
// kMuWriter and kMuReader
// kMuWrWait and !kMuWait
- const intptr_t w = v ^ kMuWait;
+ const uintptr_t w = v ^ kMuWait;
// By flipping that bit, we can now test for:
// kMuWriter and kMuReader in w
// kMuWrWait and kMuWait in w
@@ -1881,7 +1915,8 @@ void Mutex::LockSlowLoop(SynchWaitParams *waitp, int flags) {
waitp->how->fast_add,
std::memory_order_acquire, std::memory_order_relaxed)) {
if (waitp->cond == nullptr ||
- EvalConditionAnnotated(waitp->cond, this, true, waitp->how)) {
+ EvalConditionAnnotated(waitp->cond, this, true, false,
+ waitp->how == kShared)) {
break; // we timed out, or condition true, so return
}
this->UnlockSlow(waitp); // got lock but condition false
@@ -1924,7 +1959,8 @@ void Mutex::LockSlowLoop(SynchWaitParams *waitp, int flags) {
std::memory_order_release,
std::memory_order_relaxed));
if (waitp->cond == nullptr ||
- EvalConditionAnnotated(waitp->cond, this, true, waitp->how)) {
+ EvalConditionAnnotated(waitp->cond, this, true, false,
+ waitp->how == kShared)) {
break; // we timed out, or condition true, so return
}
this->UnlockSlow(waitp); // got lock but condition false
@@ -2552,7 +2588,7 @@ void CondVar::Wakeup(PerThreadSynch *w) {
}
void CondVar::Signal() {
- ABSL_TSAN_MUTEX_PRE_SIGNAL(0, 0);
+ ABSL_TSAN_MUTEX_PRE_SIGNAL(nullptr, 0);
intptr_t v;
int c = 0;
for (v = cv_.load(std::memory_order_relaxed); v != 0;
@@ -2581,17 +2617,17 @@ void CondVar::Signal() {
if ((v & kCvEvent) != 0) {
PostSynchEvent(this, SYNCH_EV_SIGNAL);
}
- ABSL_TSAN_MUTEX_POST_SIGNAL(0, 0);
+ ABSL_TSAN_MUTEX_POST_SIGNAL(nullptr, 0);
return;
} else {
c = Delay(c, GENTLE);
}
}
- ABSL_TSAN_MUTEX_POST_SIGNAL(0, 0);
+ ABSL_TSAN_MUTEX_POST_SIGNAL(nullptr, 0);
}
void CondVar::SignalAll () {
- ABSL_TSAN_MUTEX_PRE_SIGNAL(0, 0);
+ ABSL_TSAN_MUTEX_PRE_SIGNAL(nullptr, 0);
intptr_t v;
int c = 0;
for (v = cv_.load(std::memory_order_relaxed); v != 0;
@@ -2618,13 +2654,13 @@ void CondVar::SignalAll () {
if ((v & kCvEvent) != 0) {
PostSynchEvent(this, SYNCH_EV_SIGNALALL);
}
- ABSL_TSAN_MUTEX_POST_SIGNAL(0, 0);
+ ABSL_TSAN_MUTEX_POST_SIGNAL(nullptr, 0);
return;
} else {
c = Delay(c, GENTLE); // try again after a delay
}
}
- ABSL_TSAN_MUTEX_POST_SIGNAL(0, 0);
+ ABSL_TSAN_MUTEX_POST_SIGNAL(nullptr, 0);
}
void ReleasableMutexLock::Release() {
@@ -2685,5 +2721,5 @@ bool Condition::GuaranteedEqual(const Condition *a, const Condition *b) {
a->arg_ == b->arg_ && a->method_ == b->method_;
}
-} // inline namespace lts_2018_12_18
+} // inline namespace lts_2019_08_08
} // namespace absl
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