diff options
| -rw-r--r-- | runtime/debugger.cc | 9 | ||||
| -rw-r--r-- | runtime/jdwp/object_registry.cc | 15 |
2 files changed, 21 insertions, 3 deletions
diff --git a/runtime/debugger.cc b/runtime/debugger.cc index fe1e3a4aa5..229a1af6b1 100644 --- a/runtime/debugger.cc +++ b/runtime/debugger.cc @@ -819,10 +819,15 @@ void Dbg::Disconnected() { } gDebuggerActive = false; } - gRegistry->Clear(); - gDebuggerConnected = false; CHECK_EQ(self->SetStateUnsafe(old_state), kRunnable); runtime->GetThreadList()->ResumeAll(); + + { + ScopedObjectAccess soa(self); + gRegistry->Clear(); + } + + gDebuggerConnected = false; } bool Dbg::IsDebuggerActive() { diff --git a/runtime/jdwp/object_registry.cc b/runtime/jdwp/object_registry.cc index 20db368c21..e415c3d1cd 100644 --- a/runtime/jdwp/object_registry.cc +++ b/runtime/jdwp/object_registry.cc @@ -104,7 +104,20 @@ bool ObjectRegistry::ContainsLocked(Thread* self, mirror::Object* o, int32_t ide } void ObjectRegistry::Clear() { - Thread* self = Thread::Current(); + Thread* const self = Thread::Current(); + + // We must not hold the mutator lock exclusively if we want to delete weak global + // references. Otherwise this can lead to a deadlock with a running GC: + // 1. GC thread disables access to weak global references, then releases + // mutator lock. + // 2. JDWP thread takes mutator lock exclusively after suspending all + // threads. + // 3. GC thread waits for shared mutator lock which is held by JDWP + // thread. + // 4. JDWP thread clears weak global references but need to wait for GC + // thread to re-enable access to them. + Locks::mutator_lock_->AssertNotExclusiveHeld(self); + MutexLock mu(self, lock_); VLOG(jdwp) << "Object registry contained " << object_to_entry_.size() << " entries"; // Delete all the JNI references. |