Deadlock when using pseudo session clock

Deadlock when using fireUntilHalt in one thread and PseudoClockScheduler.advanceTime() in second thread.

Surroundings:
I read many events from JMS queue, each event has timestamp. I need temporal operations measured by time in timestamps. E.g. SomeEvent() over window:time(10s) means events with timestamps in interval 10s, not events inserted in interval 10s. So, I must use pseudo session clock and advance time before event insert into statefull session. Sometimes deadlock occured or NullPointerException is thrown.

I created test case.

Deadlock stacktraces:

Name: Thread-1
State: BLOCKED on org.drools.time.impl.PseudoClockScheduler@4599d5b owned by: Thread-0
Total blocked: 6 Total waited: 3

Stack trace:
org.drools.time.impl.PseudoClockScheduler.getCurrentTime(PseudoClockScheduler.java:104)
org.drools.common.AbstractWorkingMemory.endOperation(AbstractWorkingMemory.java:1345)
org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1240)

• locked org.drools.common.DefaultAgenda@57e2793d
  org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:1126)
  org.drools.common.DefaultAgenda.fireUntilHalt(DefaultAgenda.java:1327)
  org.drools.common.AbstractWorkingMemory.fireUntilHalt(AbstractWorkingMemory.java:754)
• locked org.drools.reteoo.ReteooStatefulSession@31d8d237
  org.drools.common.AbstractWorkingMemory.fireUntilHalt(AbstractWorkingMemory.java:730)
  org.drools.impl.StatefulKnowledgeSessionImpl.fireUntilHalt(StatefulKnowledgeSessionImpl.java:245)
  org.drools.integrationtests.StreamsTest$1.run(StreamsTest.java:526)
  java.lang.Thread.run(Thread.java:662)

Name: Thread-0
State: BLOCKED on org.drools.common.DefaultAgenda@57e2793d owned by: Thread-1
Total blocked: 2 Total waited: 0

Stack trace:
org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1168)
org.drools.common.Scheduler$ActivationTimerJob.execute(Scheduler.java:86)
org.drools.time.impl.DefaultTimerJobInstance.call(DefaultTimerJobInstance.java:47)
org.drools.time.impl.DefaultTimerJobInstance.call(DefaultTimerJobInstance.java:1)
org.drools.time.impl.PseudoClockScheduler.runCallBacks(PseudoClockScheduler.java:203)
org.drools.time.impl.PseudoClockScheduler.advanceTime(PseudoClockScheduler.java:156)

• locked org.drools.time.impl.PseudoClockScheduler@4599d5b
  org.drools.integrationtests.StreamsTest.processStocks(StreamsTest.java:533)
  org.drools.integrationtests.StreamsTest.testEvenFirePseudoClockRulesAB(StreamsTest.java:500)
  sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
  sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
  java.lang.reflect.Method.invoke(Method.java:597)
  org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
  org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
  org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
  org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
  org.junit.internal.runners.statements.FailOnTimeout$1.run(FailOnTimeout.java:28)