Add native support for FinalizerList.makeCircularListIfUnenqueued
Called from FinalizerReference.enqueueSentinelReference to prevent
a race where the GC updates pendingNext of the sentinel reference
before enqueueSentinelReference.
Bug: 17462553
(cherry picked from commit 3256166df40981f1f1997a5f00303712277c963f)
Change-Id: I7ad2fd250c2715d1aeb919bd548ef9aab24f30a2
diff --git a/runtime/gc/reference_processor.cc b/runtime/gc/reference_processor.cc
index d3641d1..75de623 100644
--- a/runtime/gc/reference_processor.cc
+++ b/runtime/gc/reference_processor.cc
@@ -30,8 +30,13 @@
ReferenceProcessor::ReferenceProcessor()
: process_references_args_(nullptr, nullptr, nullptr),
- preserving_references_(false), lock_("reference processor lock", kReferenceProcessorLock),
- condition_("reference processor condition", lock_) {
+ preserving_references_(false),
+ condition_("reference processor condition", *Locks::reference_processor_lock_) ,
+ soft_reference_queue_(Locks::reference_queue_soft_references_lock_),
+ weak_reference_queue_(Locks::reference_queue_weak_references_lock_),
+ finalizer_reference_queue_(Locks::reference_queue_finalizer_references_lock_),
+ phantom_reference_queue_(Locks::reference_queue_phantom_references_lock_),
+ cleared_references_(Locks::reference_queue_cleared_references_lock_) {
}
void ReferenceProcessor::EnableSlowPath() {
@@ -50,7 +55,7 @@
if (UNLIKELY(!SlowPathEnabled()) || referent == nullptr) {
return referent;
}
- MutexLock mu(self, lock_);
+ MutexLock mu(self, *Locks::reference_processor_lock_);
while (SlowPathEnabled()) {
mirror::HeapReference<mirror::Object>* const referent_addr =
reference->GetReferentReferenceAddr();
@@ -93,12 +98,12 @@
}
void ReferenceProcessor::StartPreservingReferences(Thread* self) {
- MutexLock mu(self, lock_);
+ MutexLock mu(self, *Locks::reference_processor_lock_);
preserving_references_ = true;
}
void ReferenceProcessor::StopPreservingReferences(Thread* self) {
- MutexLock mu(self, lock_);
+ MutexLock mu(self, *Locks::reference_processor_lock_);
preserving_references_ = false;
// We are done preserving references, some people who are blocked may see a marked referent.
condition_.Broadcast(self);
@@ -114,7 +119,7 @@
TimingLogger::ScopedTiming t(concurrent ? __FUNCTION__ : "(Paused)ProcessReferences", timings);
Thread* self = Thread::Current();
{
- MutexLock mu(self, lock_);
+ MutexLock mu(self, *Locks::reference_processor_lock_);
process_references_args_.is_marked_callback_ = is_marked_callback;
process_references_args_.mark_callback_ = mark_object_callback;
process_references_args_.arg_ = arg;
@@ -163,7 +168,7 @@
DCHECK(finalizer_reference_queue_.IsEmpty());
DCHECK(phantom_reference_queue_.IsEmpty());
{
- MutexLock mu(self, lock_);
+ MutexLock mu(self, *Locks::reference_processor_lock_);
// Need to always do this since the next GC may be concurrent. Doing this for only concurrent
// could result in a stale is_marked_callback_ being called before the reference processing
// starts since there is a small window of time where slow_path_enabled_ is enabled but the
@@ -225,5 +230,31 @@
}
}
+bool ReferenceProcessor::MakeCircularListIfUnenqueued(mirror::FinalizerReference* reference) {
+ Thread* self = Thread::Current();
+ MutexLock mu(self, *Locks::reference_processor_lock_);
+ // Wait untul we are done processing reference.
+ while (SlowPathEnabled()) {
+ condition_.Wait(self);
+ }
+ // At this point, since the sentinel of the reference is live, it is guaranteed to not be
+ // enqueued if we just finished processing references. Otherwise, we may be doing the main GC
+ // phase. Since we are holding the reference processor lock, it guarantees that reference
+ // processing can't begin. The GC could have just enqueued the reference one one of the internal
+ // GC queues, but since we hold the lock finalizer_reference_queue_ lock it also prevents this
+ // race.
+ MutexLock mu2(self, *Locks::reference_queue_finalizer_references_lock_);
+ if (!reference->IsEnqueued()) {
+ CHECK(reference->IsFinalizerReferenceInstance());
+ if (Runtime::Current()->IsActiveTransaction()) {
+ reference->SetPendingNext<true>(reference);
+ } else {
+ reference->SetPendingNext<false>(reference);
+ }
+ return true;
+ }
+ return false;
+}
+
} // namespace gc
} // namespace art