[jboss-jira] [JBoss JIRA] (WFLY-5596) MessageDrivenComponent startDelivery/stopDelivery is not thread safe

[James Livingston (JIRA)]

     [ https://issues.jboss.org/browse/WFLY-5596?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

James Livingston updated WFLY-5596:
-----------------------------------
    Steps to Reproduce: 
1) Take the helloworld-mdb quickstart, and add @ClusteredSingleton (from jboss-ejb3-exi-api) to a MDB.
2) Add a breakpoint on MessageDrivenBean.activate()
3) Deploy and start the server

Either one or two threads may hit the breakpoint concurrently, depending on whether the first runs "this.deliveryActive = true" before the second does the check:
org.jboss.as.ejb3.component.messagedriven.MessageDrivenComponent.activate() line: 238	
org.jboss.as.ejb3.component.messagedriven.MessageDrivenComponent.startDelivery() line: 265	
org.jboss.as.ejb3.component.messagedriven.MdbDeliveryControllerService.start(org.jboss.msc.service.StartContext) line: 51	
org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(org.jboss.msc.service.Service<? extends S>, org.jboss.msc.service.StartContext) line: 1948	
org.jboss.msc.service.ServiceControllerImpl$StartTask.run() line: 1881	
org.jboss.msc.service.ServiceContainerImpl$ContainerExecutor(java.util.concurrent.ThreadPoolExecutor).runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) line: 1142	
java.util.concurrent.ThreadPoolExecutor$Worker.run() line: 617	
org.jboss.msc.service.ServiceContainerImpl$ServiceThread(java.lang.Thread).run() line: 745	

org.jboss.as.ejb3.component.messagedriven.MessageDrivenComponent.activate() line: 238	
org.jboss.as.ejb3.component.messagedriven.MessageDrivenComponent.start() line: 214	
org.jboss.as.ee.component.ComponentStartService$1.run() line: 54	
java.util.concurrent.Executors$RunnableAdapter<T>.call() line: 511	
java.util.concurrent.FutureTask<V>.run() line: 266	
java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) line: 1142	
java.util.concurrent.ThreadPoolExecutor$Worker.run() line: 617	
org.jboss.threads.JBossThread(java.lang.Thread).run() line: 745	
org.jboss.threads.JBossThread.run() line: 320	


> MessageDrivenComponent startDelivery/stopDelivery is not thread safe
> --------------------------------------------------------------------
>
>                 Key: WFLY-5596
>                 URL: https://issues.jboss.org/browse/WFLY-5596
>             Project: WildFly
>          Issue Type: Bug
>          Components: EJB, JMS
>    Affects Versions: 10.0.0.CR4
>            Reporter: James Livingston
>            Assignee: Jeff Mesnil
>
> WFLY-4470 made a change to prevent MDBs being activated or deactivated multiple times, but it is not thread safe. A volatile boolean is used for the flag, but there is no protection against multiple threads invoking the methods simultaneously.
> Possible effects include:
> * activating the endpoint twice, with (probably) only one deactivation later, leading to not de-registering XA resources from the recovery manager properly
> * activate() and deactivate() running in the wrong order if done by separate threads
> Several simple solutions probably will not work correctly. Using an AtomicBoolean would stop multiple activations/deactivations from concurrent calls, but would mean that startDelivery() could return before the activation was one. Using a synchronized block or other exclusive lock would work, however since it involves invoking non-container code (the resource adapter), there could potentially be a deadlock risk if that invoked some related container functionality.



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