[FELIX-3910] Race conditions in DependencyManager

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: dependencymanager-3.0.0
• Fix Version/s: dependencymanager-3.2.0
• Component/s: Dependency Manager
• Environment: jdk1.6, jdk1.7, linux fc16
• Assignee: Pierre De Rop
• Reporter: Pierre De Rop
• Created: 20/Feb/13 13:30
• Updated: 21/Jul/14 22:41
• Resolved: 21/Jul/14 22:40

Description

In a multi threaded context, where dependencies are injected concurrently from different threads, we came across some exceptions which seem to take place from dependencymanager.

I have tried to reproduce the problems using a paxexam test which I will commit.
Not all exceptions are reproduced by the test case, but I think that the testcase really reproduces a problem.

I also have a candidate patch, which I will submit to this jira issue.

Here are the exceptions we have seen:

first stacktrace seen:
===============

ERROR: Bundle test.dm [21] EventDispatcher: Error during dispatch. (java.lang.NullPointerException)
java.lang.NullPointerException
at org.apache.felix.dm.impl.dependencies.ServiceDependencyImpl.addedService(ServiceDependencyImpl.java:481)
at org.apache.felix.dm.tracker.ServiceTracker$Tracked.customizerAdded(ServiceTracker.java:1325)
at org.apache.felix.dm.tracker.AbstractTracked.trackAdding(AbstractTracked.java:290)
at org.apache.felix.dm.tracker.AbstractTracked.track(AbstractTracked.java:236)
at org.apache.felix.dm.tracker.ServiceTracker$Tracked.serviceChangedHideAspects(ServiceTracker.java:1206)
at org.apache.felix.dm.tracker.ServiceTracker$Tracked.serviceChanged(ServiceTracker.java:1101)
at org.apache.felix.framework.util.EventDispatcher.invokeServiceListenerCallback(EventDispatcher.java:932)
at org.apache.felix.framework.util.EventDispatcher.fireEventImmediately(EventDispatcher.java:793)
at org.apache.felix.framework.util.EventDispatcher.fireServiceEvent(EventDispatcher.java:543)
at org.apache.felix.framework.Felix.fireServiceEvent(Felix.java:4260)
at org.apache.felix.framework.Felix.registerService(Felix.java:3275)
at org.apache.felix.framework.BundleContextImpl.registerService(BundleContextImpl.java:346)
at org.apache.felix.framework.BundleContextImpl.registerService(BundleContextImpl.java:320)
at test.dm.race.RaceTest$RegistrationHelper$1.run(RaceTest.java:104)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)

second exceptions:
==============

ERROR: EventDispatcher: Error during dispatch. (java.lang.NullPointerException)
java.lang.NullPointerException
at org.apache.felix.dm.impl.ComponentImpl.invokeCallbackMethod(ComponentImpl.java:686)
at org.apache.felix.dm.impl.dependencies.ServiceDependencyImpl.invoke(ServiceDependencyImpl.java:704)
at org.apache.felix.dm.impl.dependencies.ServiceDependencyImpl.invokeRemoved(ServiceDependencyImpl.java:666)
at org.apache.felix.dm.impl.dependencies.ServiceDependencyImpl.removedService(ServiceDependencyImpl.java:520)
at org.apache.felix.dm.tracker.ServiceTracker$Tracked.customizerRemoved(ServiceTracker.java:1351)
at org.apache.felix.dm.tracker.AbstractTracked.untrack(AbstractTracked.java:359)
at org.apache.felix.dm.tracker.ServiceTracker$Tracked.serviceChangedHideAspects(ServiceTracker.java:1285)
at org.apache.felix.dm.tracker.ServiceTracker$Tracked.serviceChanged(ServiceTracker.java:1101)
at org.apache.felix.framework.util.EventDispatcher.invokeServiceListenerCallback(EventDispatcher.java:878)
at org.apache.felix.framework.util.EventDispatcher.fireEventImmediately(EventDispatcher.java:732)
at org.apache.felix.framework.util.EventDispatcher.fireServiceEvent(EventDispatcher.java:662)
at org.apache.felix.framework.Felix.fireServiceEvent(Felix.java:3587)
at org.apache.felix.framework.Felix.access$000(Felix.java:40)
at org.apache.felix.framework.Felix$1.serviceChanged(Felix.java:625)
at org.apache.felix.framework.ServiceRegistry.unregisterService(ServiceRegistry.java:117)
at org.apache.felix.framework.ServiceRegistrationImpl.unregister(ServiceRegistrationImpl.java:128)
at org.apache.felix.dm.test.RaceTest$AFactory$2.run(RaceTest.java:151)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)