[jboss-jira] [JBoss JIRA] Closed: (JBAS-5880) Synchronization Problem in TxServerClientInterceptor

Synchronization Problem in TxServerClientInterceptor ----------------------------------------------------- Key: JBAS-5880 URL: https://jira.jboss.org/jira/browse/JBAS-5880 Project: JBoss Application Server Issue Type: Bug Security Level: Public(Everyone can see) Components: IIOP service Affects Versions: JBossAS-4.2.2.GA Reporter: Justin Bertram Assignee: Adrian Brock Fix For: JBossAS-5.0.0.CR2, JBossAS-4.2.4.GA We found a synchronization problem when starting JBoss under load. In class TxServerClientInterceptor method getEmptyPropagationContext a static member is initialized without being synchronized. While one thread is still initializing the otid member in line 100, an other thread assigns a new object to the "current" member so that otid is null. ... BINGO sniplet from TxServerClientInterceptor 090 static PropagationContext getEmptyPropagationContext() 091 { 092 if (emptyPC == null) 093 { 094 // According to the spec, this should all be ignored 095 // But we get NPEs if it doesn't contain some content 096 emptyPC = new PropagationContext(); 097 emptyPC.parents = new TransIdentity[0]; 098 emptyPC.current = new TransIdentity(); 099 emptyPC.current.otid = new otid_t(); 100 emptyPC.current.otid.formatID = 666; 101 emptyPC.current.otid.bqual_length = 1; 102 emptyPC.current.otid.tid = new byte[] { (byte) 1 }; 103 emptyPC.implementation_specific_data = ORB.init().create_any(); 104 emptyPC.implementation_specific_data.insert_boolean(false); 105 } 106 return emptyPC; The problem is that a second thread could see emptyPC as not null while the first thread is still initialising the data. The fix is to contruct a "temp" propagation context that is only assigned to emptyPC once it is fully initialised. SInce this is just a cached object, it doesn't really matter if a few threads at the start of processing initialise emptyPC multiple times, the method is "idempotent".