[jboss-jira] [JBoss JIRA] (WFLY-2496) Concurrent access to ModuleSpecification causes race condition

Concurrent access to ModuleSpecification causes race condition -------------------------------------------------------------- Key: WFLY-2496 URL: https://issues.jboss.org/browse/WFLY-2496 Project: WildFly Issue Type: Bug Security Level: Public(Everyone can see) Components: Server Affects Versions: 8.0.0.Beta1 Reporter: Jozef Hartinger Assignee: Jason Greene Priority: Blocker Fix For: 8.0.0.Final [ModuleSpecification|https://github.com/wildfly/wildfly/blob/master/server...] does not use any form of synchronization to protect its mutable state yet may be used from multiple threads in multi-module deployment when a DeploymentUnitProcessor touches ModuleSpecification of a different deployment unit which is processed at that moment. Here is an example of such access: https://github.com/wildfly/wildfly/blob/master/jsf/subsystem/src/main/jav... Here's how I think this problem manifests: {noformat} Caused by: java.lang.NullPointerException at org.jboss.as.server.deployment.module.ModuleSpecProcessor.createDependencies(ModuleSpecProcessor.java:284) [wildfly-server-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT] at org.jboss.as.server.deployment.module.ModuleSpecProcessor.createModuleService(ModuleSpecProcessor.java:220) [wildfly-server-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT] at org.jboss.as.server.deployment.module.ModuleSpecProcessor.deployModuleSpec(ModuleSpecProcessor.java:125) [wildfly-server-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT] at org.jboss.as.server.deployment.module.ModuleSpecProcessor.deploy(ModuleSpecProcessor.java:88) [wildfly-server-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT] at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:159) [wildfly-server-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT] ... 5 more {noformat} and here's my attempt to verify concurrent access by changing the code slightly to deadlock on concurrent access: {noformat} "MSC service thread 1-6": at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000f742ba28> (a java.util.concurrent.locks.ReentrantLock$NonfairSync) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186) at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:834) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:867) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1197) at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:214) at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:290) at org.jboss.as.server.deployment.module.ModuleSpecification.foo(ModuleSpecification.java:170) at org.jboss.as.server.deployment.module.ModuleSpecification.addSystemDependency(ModuleSpecification.java:121) at org.jboss.as.jsf.deployment.JSFDependencyProcessor.addJSFAPI(JSFDependencyProcessor.java:115) at org.jboss.as.jsf.deployment.JSFDependencyProcessor.deploy(JSFDependencyProcessor.java:93) at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:159) - locked <0x00000000f69a8e88> (a org.jboss.as.server.deployment.DeploymentUnitPhaseService) at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1944) at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1877) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:744) "MSC service thread 1-3": at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000f742ba58> (a java.util.concurrent.locks.ReentrantLock$NonfairSync) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186) at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:834) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:867) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1197) at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:214) at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:290) at org.jboss.as.server.deployment.module.ModuleSpecification.foo(ModuleSpecification.java:175) at org.jboss.as.server.deployment.module.ModuleSpecification.addSystemDependency(ModuleSpecification.java:121) at org.jboss.as.jsf.deployment.JSFDependencyProcessor.addJSFAPI(JSFDependencyProcessor.java:115) at org.jboss.as.jsf.deployment.JSFDependencyProcessor.deploy(JSFDependencyProcessor.java:93) at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:159) - locked <0x00000000f6782960> (a org.jboss.as.server.deployment.DeploymentUnitPhaseService) at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1944) at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1877) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:744) {noformat}