[FELIX-3345] Concurrency problems in SCR

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: scr-1.6.0
• Fix Version/s: scr-1.6.2
• Component/s: Declarative Services (SCR)
• Assignee: Felix Meschberger
• Reporter: David Jencks
• Created: 09/Feb/12 22:49
• Updated: 01/Aug/15 11:25
• Resolved: 28/Nov/12 23:37

Description

We've been encountering several exceptions thrown intermittently from DS. They generally look like ungetting service on a disposed-of SCR BundleComponentActivator, ComponentManager, or DependencyManager. There may be two threads trying to shut down the same bundles at the same time. I'm not sure how to investigate the root cause or if this kind of behavior is expected. The SCR code generally doesn't look very thread safe. It's easy to "fix" the specific problems we see by adding more checks to the SCR code so the NPEs are avoided, or attempted use of closed bundle contexts are caught and ignored. I'd be happy to keep looking into this but could use some hints about what should be happening. Unless someone can come up with a better explanation and fix it would be great meanwhile to patch the code to avoid throwing the exceptions.

Here are some of the typical stack traces we see:

Stack Dump = org.osgi.framework.ServiceException: Exception in org.apache.felix.scr.impl.manager.DelayedComponentManager.ungetService()
at org.eclipse.osgi.internal.serviceregistry.ServiceUse.releaseService(ServiceUse.java:287)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistrationImpl.releaseService(ServiceRegistrationImpl.java:562)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistry.releaseServicesInUse(ServiceRegistry.java:665)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.close(BundleContextImpl.java:91)
at org.eclipse.osgi.framework.internal.core.BundleHost.stopWorker(BundleHost.java:514)
at org.eclipse.osgi.framework.internal.core.AbstractBundle.suspend(AbstractBundle.java:565)
at org.eclipse.osgi.framework.internal.core.Framework.suspendBundle(Framework.java:1161)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.decFWSL(StartLevelManager.java:595)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:257)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.shutdown(StartLevelManager.java:215)
at org.eclipse.osgi.framework.internal.core.InternalSystemBundle.suspend(InternalSystemBundle.java:284)
at org.eclipse.osgi.framework.internal.core.Framework.shutdown(Framework.java:691)
at org.eclipse.osgi.framework.internal.core.Framework.close(Framework.java:598)
at org.eclipse.osgi.framework.internal.core.InternalSystemBundle$1.run(InternalSystemBundle.java:261)
at java.lang.Thread.run(Thread.java:680)
Caused by: java.lang.NullPointerException
at org.apache.felix.scr.impl.BundleComponentActivator.log(BundleComponentActivator.java:614)
at org.apache.felix.scr.impl.BundleComponentActivator.log(BundleComponentActivator.java:589)
at org.apache.felix.scr.impl.manager.AbstractComponentManager.log(AbstractComponentManager.java:633)
at org.apache.felix.scr.impl.manager.AbstractComponentManager$State.log(AbstractComponentManager.java:1000)
at org.apache.felix.scr.impl.manager.AbstractComponentManager$State.ungetService(AbstractComponentManager.java:964)
at org.apache.felix.scr.impl.manager.DelayedComponentManager.ungetService(DelayedComponentManager.java:114)
at org.eclipse.osgi.internal.serviceregistry.ServiceUse$3.run(ServiceUse.java:277)
at java.security.AccessController.doPrivileged(Native Method)
at org.eclipse.osgi.internal.serviceregistry.ServiceUse.releaseService(ServiceUse.java:275)
... 14 more

Stack Dump = org.osgi.framework.ServiceException: Exception in org.apache.felix.scr.impl.manager.DelayedComponentManager.ungetService()
at org.eclipse.osgi.internal.serviceregistry.ServiceUse.releaseService(ServiceUse.java:287)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistrationImpl.releaseService(ServiceRegistrationImpl.java:562)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistrationImpl.unregister(ServiceRegistrationImpl.java:245)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistry.unregisterServices(ServiceRegistry.java:635)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.close(BundleContextImpl.java:88)
at org.eclipse.osgi.framework.internal.core.BundleHost.stopWorker(BundleHost.java:514)
at org.eclipse.osgi.framework.internal.core.AbstractBundle.suspend(AbstractBundle.java:565)
at org.eclipse.osgi.framework.internal.core.Framework.suspendBundle(Framework.java:1161)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.decFWSL(StartLevelManager.java:595)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:257)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.shutdown(StartLevelManager.java:215)
at org.eclipse.osgi.framework.internal.core.InternalSystemBundle.suspend(InternalSystemBundle.java:284)
at org.eclipse.osgi.framework.internal.core.Framework.shutdown(Framework.java:691)
at org.eclipse.osgi.framework.internal.core.Framework.close(Framework.java:598)
at org.eclipse.osgi.framework.internal.core.InternalSystemBundle$1.run(InternalSystemBundle.java:261)
at java.lang.Thread.run(Thread.java:680)
Caused by: java.lang.IllegalStateException: BundleContext is no longer valid
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.checkValid(BundleContextImpl.java:931)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.ungetService(BundleContextImpl.java:634)
at org.apache.felix.scr.impl.manager.DependencyManager.ungetService(DependencyManager.java:819)
at org.apache.felix.scr.impl.manager.DependencyManager.unbind(DependencyManager.java:1000)
at org.apache.felix.scr.impl.manager.DependencyManager.close(DependencyManager.java:880)
at org.apache.felix.scr.impl.manager.ImmediateComponentManager.disposeImplementationObject(ImmediateComponentManager.java:268)
at org.apache.felix.scr.impl.manager.ImmediateComponentManager.deleteComponent(ImmediateComponentManager.java:135)
at org.apache.felix.scr.impl.manager.DelayedComponentManager.deleteComponent(DelayedComponentManager.java:67)
at org.apache.felix.scr.impl.manager.AbstractComponentManager$Active.ungetService(AbstractComponentManager.java:1266)
at org.apache.felix.scr.impl.manager.DelayedComponentManager.ungetService(DelayedComponentManager.java:114)
at org.eclipse.osgi.internal.serviceregistry.ServiceUse$3.run(ServiceUse.java:277)
at java.security.AccessController.doPrivileged(Native Method)
at org.eclipse.osgi.internal.serviceregistry.ServiceUse.releaseService(ServiceUse.java:275)
... 15 more

-------
This one is from FELIX-3307:

java.lang.NullPointerException
at org.apache.felix.scr.impl.manager.DependencyManager.invokeBindMethod(DependencyManager.java:1028)
at org.apache.felix.scr.impl.manager.DependencyManager.serviceAdded(DependencyManager.java:308)
at org.apache.felix.scr.impl.manager.DependencyManager.serviceChanged(DependencyManager.java:170)
at org.eclipse.osgi.internal.serviceregistry.FilteredServiceListener.serviceChanged(FilteredServiceListener.java:104)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.dispatchEvent(BundleContextImpl.java:861)
at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
at org.eclipse.osgi.framework.eventmgr.ListenerQueue.dispatchEventSynchronous(ListenerQueue.java:148)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistry.publishServiceEventPrivileged(ServiceRegistry.java:819)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistry.publishServiceEvent(ServiceRegistry.java:771)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistrationImpl.register(ServiceRegistrationImpl.java:130)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistry.registerService(ServiceRegistry.java:214)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.registerService(BundleContextImpl.java:433)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.registerService(BundleContextImpl.java:451)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.registerService(BundleContextImpl.java:950)

Issue Links

• incorporates: FELIX-3307 NPE in DependencyManager.invokeBindMethod