[jboss-jira] [JBoss JIRA] Resolved: (JGRP-447) Non-thread-safe access to FC.creditors

Non-thread-safe access to FC.creditors -------------------------------------- Key: JGRP-447 URL: http://jira.jboss.com/jira/browse/JGRP-447 Project: JGroups Issue Type: Bug Affects Versions: 2.4.1 SP1 Reporter: Brian Stansberry Assigned To: Bela Ban Fix For: 2.4.1 SP2 During load testing of AS HttpSession repl, QE saw RPC transmission errors with the following root cause: [JBoss] Caused by: java.lang.IndexOutOfBoundsException: Index: 1, Size: 1 [JBoss] at java.util.ArrayList.RangeCheck(ArrayList.java:546) [JBoss] at java.util.ArrayList.get(ArrayList.java:321) [JBoss] at org.jgroups.protocols.FC.handleDownMessage(FC.java:390) [JBoss] at org.jgroups.protocols.FC.down(FC.java:320) [JBoss] at org.jgroups.stack.Protocol.receiveDownEvent(Protocol.java:517) [JBoss] at org.jgroups.protocols.FC.receiveDownEvent(FC.java:314) [JBoss] at org.jgroups.stack.Protocol.passDown(Protocol.java:551) [JBoss] at org.jgroups.protocols.FRAG2.down(FRAG2.java:167) [JBoss] at org.jgroups.stack.Protocol.receiveDownEvent(Protocol.java:517) [JBoss] at org.jgroups.stack.Protocol.passDown(Protocol.java:551) [JBoss] at org.jgroups.protocols.pbcast.STATE_TRANSFER.down(STATE_TRANSFER.java:294) [JBoss] at org.jgroups.stack.Protocol.receiveDownEvent(Protocol.java:517) [JBoss] at org.jgroups.stack.ProtocolStack.down(ProtocolStack.java:385) [JBoss] at org.jgroups.JChannel.down(JChannel.java:1231) [JBoss] at org.jgroups.blocks.MessageDispatcher$ProtocolAdapter.down(MessageDispatcher.java:788) [JBoss] at org.jgroups.blocks.MessageDispatcher$ProtocolAdapter.passDown(MessageDispatcher.java:765) [JBoss] at org.jgroups.blocks.RequestCorrelator.sendRequest(RequestCorrelator.java:299) [JBoss] at org.jgroups.blocks.GroupRequest.doExecute(GroupRequest.java:444) [JBoss] at org.jgroups.blocks.GroupRequest.execute(GroupRequest.java:193) [JBoss] at org.jgroups.blocks.MessageDispatcher.castMessage(MessageDispatcher.java:429) Having a look at FC, in handleDownMessage(), where the problem occurred, there's this: Util.release(lock); try { ... for(int i=0; i < creditors.size(); i++) { sendCreditRequest((Address)creditors.get(i)); } } .... in handleCredit() there's: if(Util.acquire(lock)) { ... if(creditors.size() > 0) { // we are blocked because we expect credit from one or more members creditors.remove(sender); ... } ... } If the creditors.remove(sender) call is invoked while the handleDownMessage for loop is looping, there's a possibility of IndexOutOfBoundsException.