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https://issues.apache.org/jira/browse/FELIX-3687?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13465794#comment-13465794
]
David Jencks commented on FELIX-3687:
-------------------------------------
Looking at the code I think that putting the service registration into
m_lockedRegsMap and then calling ungetService will result in an exception when
ungetService tries to lock the thread.
what about
1. get clients in synchronized block
2. invalidate registration
3. directly call reg.ungetService
4. flush usage (can this be done earlier in the synchronized block?)
I think this would replicate the effect of ungetService without the locking
with presumably wouldn't be so needed if the reg. is invalidated?
> Deadlock potential from ServiceRegistry.unregisterService
> ---------------------------------------------------------
>
> Key: FELIX-3687
> URL: https://issues.apache.org/jira/browse/FELIX-3687
> Project: Felix
> Issue Type: Bug
> Components: Framework
> Affects Versions: framework-4.0.3
> Reporter: David Jencks
> Attachments: FELIX-3687-1.diff
>
>
> At the end of unregisterService there's this block:
> {code}
> // Now forcibly unget the service object for all stubborn clients.
> synchronized (this)
> {
> Bundle[] clients = getUsingBundles(reg.getReference());
> for (int i = 0; (clients != null) && (i < clients.length); i++)
> {
> while (ungetService(clients[i], reg.getReference()))
> ; // Keep removing until it is no longer possible
> }
> ((ServiceRegistrationImpl) reg).invalidate();
> }
> {code}
> Note the call to ungetService from within a synchronized block. ungetService
> itself is very careful to release the lock before calling out to the service
> factory, however this call from unregisterService negates this care.
> This causes problems with DS with thread dumps like:
> {code}
> ThreadId: 16 : name: SCR Component Actor State: RUNNABLE
> LockInfo: null LockOwnerId: -1 LockOwnerName: null
> sun.management.ThreadImpl.dumpThreads0(Native Method)
> sun.management.ThreadImpl.dumpAllThreads(ThreadImpl.java:433)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager.dumpThreads(AbstractComponentManager.java:294)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager.logLockingInfo(AbstractComponentManager.java:240)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager.releaseReadLock(AbstractComponentManager.java:222)
>
> org.apache.felix.scr.impl.manager.ImmediateComponentManager.ungetService(ImmediateComponentManager.java:710)
>
> org.apache.felix.framework.ServiceRegistrationImpl.ungetFactoryUnchecked(ServiceRegistrationImpl.java:349)
>
> org.apache.felix.framework.ServiceRegistrationImpl.ungetService(ServiceRegistrationImpl.java:258)
>
> org.apache.felix.framework.ServiceRegistry.ungetService(ServiceRegistry.java:389)
> org.apache.felix.framework.Felix.ungetService(Felix.java:3432)
>
> org.apache.felix.framework.BundleContextImpl.ungetService(BundleContextImpl.java:486)
>
> org.apache.felix.scr.impl.manager.DependencyManager.ungetService(DependencyManager.java:900)
>
> org.apache.felix.scr.impl.manager.DependencyManager.unbind(DependencyManager.java:1138)
>
> org.apache.felix.scr.impl.manager.DependencyManager.close(DependencyManager.java:970)
>
> org.apache.felix.scr.impl.manager.ImmediateComponentManager.disposeImplementationObject(ImmediateComponentManager.java:276)
>
> org.apache.felix.scr.impl.manager.ImmediateComponentManager.deleteComponent(ImmediateComponentManager.java:148)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager$Active.ungetService(AbstractComponentManager.java:1718)
>
> org.apache.felix.scr.impl.manager.ImmediateComponentManager.ungetService(ImmediateComponentManager.java:695)
>
> org.apache.felix.framework.ServiceRegistrationImpl.ungetFactoryUnchecked(ServiceRegistrationImpl.java:349)
>
> org.apache.felix.framework.ServiceRegistrationImpl.ungetService(ServiceRegistrationImpl.java:258)
>
> org.apache.felix.framework.ServiceRegistry.ungetService(ServiceRegistry.java:389)
> >>>>>>>>inside the lock
> >>>>>>>>org.apache.felix.framework.ServiceRegistry.unregisterService(ServiceRegistry.java:158)
>
> org.apache.felix.framework.ServiceRegistrationImpl.unregister(ServiceRegistrationImpl.java:127)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager.unregisterComponentService(AbstractComponentManager.java:779)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager$State.doDeactivate(AbstractComponentManager.java:1387)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager$Satisfied.deactivate(AbstractComponentManager.java:1665)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager.deactivateInternal(AbstractComponentManager.java:635)
>
> org.apache.felix.scr.impl.manager.DependencyManager.serviceRemoved(DependencyManager.java:375)
>
> org.apache.felix.scr.impl.manager.DependencyManager.serviceChanged(DependencyManager.java:217)
>
> org.apache.felix.framework.util.EventDispatcher.invokeServiceListenerCallback(EventDispatcher.java:932)
>
> org.apache.felix.framework.util.EventDispatcher.fireEventImmediately(EventDispatcher.java:793)
>
> org.apache.felix.framework.util.EventDispatcher.fireServiceEvent(EventDispatcher.java:543)
> org.apache.felix.framework.Felix.fireServiceEvent(Felix.java:4260)
> org.apache.felix.framework.Felix.access$000(Felix.java:74)
> org.apache.felix.framework.Felix$1.serviceChanged(Felix.java:390)
>
> org.apache.felix.framework.ServiceRegistry.unregisterService(ServiceRegistry.java:148)
>
> org.apache.felix.framework.ServiceRegistrationImpl.unregister(ServiceRegistrationImpl.java:127)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager.unregisterComponentService(AbstractComponentManager.java:779)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager$State.doDeactivate(AbstractComponentManager.java:1387)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager$Disabled.deactivate(AbstractComponentManager.java:1461)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager.deactivateInternal(AbstractComponentManager.java:635)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager$2.run(AbstractComponentManager.java:435)
>
> org.apache.felix.scr.impl.ComponentActorThread.run(ComponentActorThread.java:98)
> java.lang.Thread.run(Thread.java:680)
> ThreadId: 67 : name: pool-1-thread-49 State: BLOCKED
> LockInfo: org.apache.felix.framework.ServiceRegistry@26d66426 LockOwnerId:
> 16 LockOwnerName: SCR Component Actor
>
> org.apache.felix.framework.ServiceRegistry.getServiceReferences(ServiceRegistry.java:204)
> org.apache.felix.framework.Felix.getServiceReferences(Felix.java:3310)
>
> org.apache.felix.framework.Felix.getAllowedServiceReferences(Felix.java:3383)
>
> org.apache.felix.framework.BundleContextImpl.getServiceReferences(BundleContextImpl.java:432)
>
> org.apache.felix.scr.impl.manager.DependencyManager.getFrameworkServiceReferences(DependencyManager.java:658)
>
> org.apache.felix.scr.impl.manager.DependencyManager.getFrameworkServiceReferences(DependencyManager.java:634)
>
> org.apache.felix.scr.impl.manager.DependencyManager.enable(DependencyManager.java:551)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager.enableDependencyManagers(AbstractComponentManager.java:1061)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager.access$600(AbstractComponentManager.java:63)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager$Disabled.enable(AbstractComponentManager.java:1445)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager.enableInternal(AbstractComponentManager.java:625)
>
> org.apache.felix.scr.impl.manager.AbstractComponentManager.enable(AbstractComponentManager.java:358)
>
> org.apache.felix.scr.impl.config.ImmediateComponentHolder.enableComponents(ImmediateComponentHolder.java:384)
>
> org.apache.felix.scr.impl.BundleComponentActivator.enableComponent(BundleComponentActivator.java:395)
>
> org.apache.felix.scr.impl.manager.ComponentContextImpl.enableComponent(ComponentContextImpl.java:101)
> test.scr.Main$EnableManager$1.run(Main.java:56)
>
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
>
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
> java.lang.Thread.run(Thread.java:680)
> {code}
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