After user logout from the XWiki, following exception occurs: 2013-07-11 12:38:47,440 [http://localhost:8080/xwiki/bin/logout/XWiki/XWikiLogout?xredirect=/xwiki/b…] ERROR c.x.x.w.XWikiAction - Cannot send action notifications for document [XWiki.XWikiLogout using action [logout] java.lang.StackOverflowError: null at java.net.AbstractPlainSocketImpl.available(AbstractPlainSocketImpl.java:455) ~[na:1.6.0_27] at java.net.SocketInputStream.available(SocketInputStream.java:234) ~[na:1.6.0_27] at com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:72) ~[mysql-connector-java-5.1.25-bin.jar:na] at com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:161) ~[mysql-connector-java-5.1.25-bin.jar:na] at com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:189) ~[mysql-connector-java-5.1.25-bin.jar:na] at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3116) ~[mysql-connector-java-5.1.25-bin.jar:na] at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3570) ~[mysql-connector-java-5.1.25-bin.jar:na] at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3559) ~[mysql-connector-java-5.1.25-bin.jar:na] at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4110) ~[mysql-connector-java-5.1.25-bin.jar:na] at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2570) ~[mysql-connector-java-5.1.25-bin.jar:na] at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2731) ~[mysql-connector-java-5.1.25-bin.jar:na] at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2809) ~[mysql-connector-java-5.1.25-bin.jar:na] at com.mysql.jdbc.ConnectionImpl.rollbackNoChecks(ConnectionImpl.java:5165) ~[mysql-connector-java-5.1.25-bin.jar:na] at com.mysql.jdbc.ConnectionImpl.rollback(ConnectionImpl.java:5048) ~[mysql-connector-java-5.1.25-bin.jar:na] at org.apache.commons.dbcp.DelegatingConnection.rollback(DelegatingConnection.java:368) ~[commons-dbcp-1.3.jar:1.3] at org.apache.commons.dbcp.DelegatingConnection.rollback(DelegatingConnection.java:368) ~[commons-dbcp-1.3.jar:1.3] at org.apache.commons.dbcp.PoolableConnectionFactory.passivateObject(PoolableConnectionFactory.java:685) ~[commons-dbcp-1.3.jar:1.3] at org.apache.commons.pool.impl.GenericObjectPool.addObjectToPool(GenericObjectPool.java:1379) ~[commons-pool-1.5.4.jar:1.5.4] at org.apache.commons.pool.impl.GenericObjectPool.returnObject(GenericObjectPool.java:1342) ~[commons-pool-1.5.4.jar:1.5.4] at org.apache.commons.dbcp.PoolableConnection.close(PoolableConnection.java:90) ~[commons-dbcp-1.3.jar:1.3] at org.apache.commons.dbcp.PoolingDataSource $PoolGuardConnectionWrapper.close(PoolingDataSource.java:191) ~[commons-dbcp-1.3.jar:1.3] at com.xpn.xwiki.store.DBCPConnectionProvider.closeConnection(DBCPConnectionProvider.java:236) ~[xwiki-platform-legacy-oldcore-4.5.3.jar:na] at org.hibernate.jdbc.ConnectionManager.closeConnection(ConnectionManager.java:474) ~[hibernate-core-3.6.9.Final.jar:3.6.9.Final] at org.hibernate.jdbc.ConnectionManager.cleanup(ConnectionManager.java:408) ~[hibernate-core-3.6.9.Final.jar:3.6.9.Final] at org.hibernate.jdbc.ConnectionManager.close(ConnectionManager.java:347) ~[hibernate-core-3.6.9.Final.jar:3.6.9.Final] at org.hibernate.impl.SessionImpl.close(SessionImpl.java:343) ~[hibernate-core-3.6.9.Final.jar:3.6.9.Final] at com.xpn.xwiki.store.XWikiHibernateBaseStore.closeSession(XWikiHibernateBaseStore.java:993) ~[xwiki-platform-legacy-oldcore-4.5.3.jar:na] at com.xpn.xwiki.store.XWikiHibernateBaseStore.endTransaction(XWikiHibernateBaseStore.java:954) ~[xwiki-platform-legacy-oldcore-4.5.3.jar:na] at com.xpn.xwiki.store.XWikiHibernateStore.releaseAllLocksForCurrentUser(XWikiHibernateStore.java:1749) ~[xwiki-platform-legacy-oldcore-4.5.3.jar:na] ... few hundred lines here ... at com.xpn.xwiki.store.XWikiHibernateStore.releaseAllLocksForCurrentUser(XWikiHibernateStore.java:1768) ~[xwiki-platform-legacy-oldcore-4.5.3.jar:na] Maybe there is something wrong with used SAML STS authentcation (suspected code can be found at https://github.com/ValdisVitolins/munixwiki/blob/master/tools/xwiki-authent… ) though I didn't find any reasonable differences from https://github.com/xwiki-contrib/sandbox/blob/master/authenticators/xwiki-a… ... Thanks in advance for any idea! Valdis