NPE or AssertionError if op is cancelled on slave between sending prepare and receiving commit/rollback ------------------------------------------------------------------------------------------------------- Key: WFCORE-1016 URL: https://issues.jboss.org/browse/WFCORE-1016 Project: WildFly Core Issue Type: Bug Components: Domain Management Affects Versions: 2.0.0.CR5 Reporter: Brian Stansberry Assignee: Brian Stansberry Fix For: 2.0.0.CR7 OperationCancellationTestCase showed this failure: {code} 2015-09-23 06:43:40,147 INFO [org.jboss.as.test.integration.management.extension.blocker.BlockerExtension] (Host Controller Service Threads - 82) block requested by testSlaveBlockCompletionCancelSlave for slave/undefined(COMMIT) 2015-09-23 06:43:40,147 INFO [org.jboss.as.test.integration.management.extension.blocker.BlockerExtension] (Host Controller Service Threads - 82) will block at COMMIT for 20000 2015-09-23 06:43:40,164 INFO [org.jboss.as.controller.management-operation] (Host Controller Service Threads - 71) WFLYCTL0352: Cancelling operation 'block' with id '1900489784' running on thread 'Host Controller Service Threads - 82' 2015-09-23 06:43:40,185 ERROR [stderr] (Host Controller Service Threads - 82) Exception in thread "Host Controller Service Threads - 82" java.lang.AssertionError 2015-09-23 06:43:40,185 ERROR [stderr] (Host Controller Service Threads - 82) at org.jboss.as.controller.remote.TransactionalProtocolOperationHandler$ExecuteRequestContext.completed(TransactionalProtocolOperationHandler.java:475) 2015-09-23 06:43:40,186 ERROR [stderr] (Host Controller Service Threads - 82) at org.jboss.as.controller.remote.TransactionalProtocolOperationHandler$ExecuteRequestHandler.doExecute(TransactionalProtocolOperationHandler.java:190) 2015-09-23 06:43:40,186 ERROR [stderr] (Host Controller Service Threads - 82) at org.jboss.as.controller.remote.TransactionalProtocolOperationHandler$ExecuteRequestHandler$1.run(TransactionalProtocolOperationHandler.java:136) 2015-09-23 06:43:40,186 ERROR [stderr] (Host Controller Service Threads - 82) at org.jboss.as.controller.remote.TransactionalProtocolOperationHandler$ExecuteRequestHandler$1.run(TransactionalProtocolOperationHandler.java:132) 2015-09-23 06:43:40,186 ERROR [stderr] (Host Controller Service Threads - 82) at java.security.AccessController.doPrivileged(Native Method) 2015-09-23 06:43:40,186 ERROR [stderr] (Host Controller Service Threads - 82) at javax.security.auth.Subject.doAs(Subject.java:360) 2015-09-23 06:43:40,186 ERROR [stderr] (Host Controller Service Threads - 82) at org.jboss.as.controller.AccessAuditContext.doAs(AccessAuditContext.java:81) 2015-09-23 06:43:40,186 ERROR [stderr] (Host Controller Service Threads - 82) at org.jboss.as.controller.remote.TransactionalProtocolOperationHandler$ExecuteRequestHandler$2$1.run(TransactionalProtocolOperationHandler.java:152) 2015-09-23 06:43:40,186 ERROR [stderr] (Host Controller Service Threads - 82) at org.jboss.as.controller.remote.TransactionalProtocolOperationHandler$ExecuteRequestHandler$2$1.run(TransactionalProtocolOperationHandler.java:148) 2015-09-23 06:43:40,187 ERROR [stderr] (Host Controller Service Threads - 82) at java.security.AccessController.doPrivileged(Native Method) 2015-09-23 06:43:40,187 ERROR [stderr] (Host Controller Service Threads - 82) at org.jboss.as.controller.remote.TransactionalProtocolOperationHandler$ExecuteRequestHandler$2.execute(TransactionalProtocolOperationHandler.java:148) 2015-09-23 06:43:40,187 ERROR [stderr] (Host Controller Service Threads - 82) at org.jboss.as.protocol.mgmt.AbstractMessageHandler$2$1.doExecute(AbstractMessageHandler.java:299) 2015-09-23 06:43:40,187 ERROR [stderr] (Host Controller Service Threads - 82) at org.jboss.as.protocol.mgmt.AbstractMessageHandler$AsyncTaskRunner.run(AbstractMessageHandler.java:519) 2015-09-23 06:43:40,187 ERROR [stderr] (Host Controller Service Threads - 82) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) 2015-09-23 06:43:40,187 ERROR [stderr] (Host Controller Service Threads - 82) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) 2015-09-23 06:43:40,187 ERROR [stderr] (Host Controller Service Threads - 82) at java.lang.Thread.run(Thread.java:745) 2015-09-23 06:43:40,187 ERROR [stderr] (Host Controller Service Threads - 82) at org.jboss.threads.JBossThread.run(JBossThread.java:320) {code} What happens here is the slave HC executing the 'block' op has sent a prepare message to the master, and then when the commit has not come back yet the test driver triggers a cancel on the slave. At this point the thread running the 'block' op returns and tries to send the final result to the master. But it fails because the prepare logic has nulled out the responseChannel field, and the commit message has not arrived yet to restore a new one. If assertions weren't enabled, the result would be an NPE when the null responseChannel is used. I don't see any reason for null out the responseChannel.