Stack dump shows deadlock:
Name: http-192.168.5.2-8180-5
State: BLOCKED on java.lang.Object@2afbf7 owned by: http-192.168.5.2-8180-4
Total blocked: 35,522 Total waited: 401

Stack trace:
java.lang.Object.wait(Native Method)
org.jgroups.protocols.FC.handleDownMessage(FC.java:360)
org.jgroups.protocols.FC.down(FC.java:300)
org.jgroups.stack.Protocol.receiveDownEvent(Protocol.java:517)
org.jgroups.protocols.FC.receiveDownEvent(FC.java:294)
org.jgroups.stack.Protocol.passDown(Protocol.java:551)
org.jgroups.protocols.FRAG2.down(FRAG2.java:167)
org.jgroups.stack.Protocol.receiveDownEvent(Protocol.java:517)
org.jgroups.stack.Protocol.passDown(Protocol.java:551)
org.jgroups.protocols.pbcast.STATE_TRANSFER.down(STATE_TRANSFER.java:276)
org.jgroups.stack.Protocol.receiveDownEvent(Protocol.java:517)
org.jgroups.stack.ProtocolStack.down(ProtocolStack.java:385)
org.jgroups.JChannel.down(JChannel.java:1175)
org.jgroups.blocks.MessageDispatcher$ProtocolAdapter.down(MessageDispatcher.java:776)
org.jgroups.blocks.MessageDispatcher$ProtocolAdapter.passDown(MessageDispatcher.java:753)
org.jgroups.blocks.RequestCorrelator.sendRequest(RequestCorrelator.java:286)
org.jgroups.blocks.GroupRequest.doExecute(GroupRequest.java:439)
org.jgroups.blocks.GroupRequest.execute(GroupRequest.java:189)
org.jgroups.blocks.MessageDispatcher.castMessage(MessageDispatcher.java:424)
org.jgroups.blocks.RpcDispatcher.callRemoteMethods(RpcDispatcher.java:178)
org.jboss.cache.TreeCache.callRemoteMethods(TreeCache.java:4160)
org.jboss.cache.TreeCache.callRemoteMethods(TreeCache.java:4114)
org.jboss.cache.TreeCache.callRemoteMethods(TreeCache.java:4215)
org.jboss.cache.interceptors.BaseRpcInterceptor.replicateCall(BaseRpcInterceptor.java:110)
org.jboss.cache.interceptors.BaseRpcInterceptor.replicateCall(BaseRpcInterceptor.java:88)
org.jboss.cache.interceptors.ReplicationInterceptor.handleReplicatedMethod(ReplicationInterceptor.java:114)
org.jboss.cache.interceptors.ReplicationInterceptor.invoke(ReplicationInterceptor.java:83)
org.jboss.cache.interceptors.Interceptor.invoke(Interceptor.java:68)
org.jboss.cache.interceptors.TxInterceptor.handleNonTxMethod(TxInterceptor.java:345)
org.jboss.cache.interceptors.TxInterceptor.invoke(TxInterceptor.java:156)
org.jboss.cache.interceptors.Interceptor.invoke(Interceptor.java:68)
org.jboss.cache.interceptors.CacheMgmtInterceptor.invoke(CacheMgmtInterceptor.java:167)
org.jboss.cache.TreeCache.invokeMethod(TreeCache.java:5520)
org.jboss.cache.TreeCache.put(TreeCache.java:3601)
sun.reflect.GeneratedMethodAccessor122.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:585)
org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
org.jboss.system.server.jmx.LazyMBeanServer.invoke(LazyMBeanServer.java:279)
org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210)
$Proxy58.put(Unknown Source)
org.jboss.web.tomcat.tc5.session.JBossCacheWrapper.put(JBossCacheWrapper.java:141)
org.jboss.web.tomcat.tc5.session.JBossCacheService.putSession(JBossCacheService.java:315)
org.jboss.web.tomcat.tc5.session.JBossCacheClusteredSession.processSessionRepl(JBossCacheClusteredSession.java:122)
org.jboss.web.tomcat.tc5.session.JBossCacheManager.processSessionRepl(JBossCacheManager.java:1094)
org.jboss.web.tomcat.tc5.session.JBossCacheManager.storeSession(JBossCacheManager.java:649)
org.jboss.web.tomcat.tc5.session.InstantSnapshotManager.snapshot(InstantSnapshotManager.java:49)
org.jboss.web.tomcat.tc5.session.ClusteredSessionValve.invoke(ClusteredSessionValve.java:98)
org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:74)
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
org.jboss.web.tomcat.tc5.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:153)
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112)
java.lang.Thread.run(Thread.java:595)

Name: http-192.168.5.2-8180-4
State: BLOCKED on org.jgroups.protocols.UNICAST$Entry@13e6987 owned by: IncomingPacketHandler (channel=Tomcat-Cluster)
Total blocked: 39,178 Total waited: 490

Stack trace:
org.jgroups.protocols.UNICAST.down(UNICAST.java:264)
org.jgroups.stack.Protocol.receiveDownEvent(Protocol.java:517)
org.jgroups.stack.Protocol.passDown(Protocol.java:551)
org.jgroups.protocols.pbcast.STABLE.down(STABLE.java:283)
org.jgroups.stack.Protocol.receiveDownEvent(Protocol.java:517)
org.jgroups.stack.Protocol.passDown(Protocol.java:551)
org.jgroups.protocols.pbcast.GMS.down(GMS.java:809)
org.jgroups.stack.Protocol.receiveDownEvent(Protocol.java:517)
org.jgroups.stack.Protocol.passDown(Protocol.java:551)
org.jgroups.protocols.FC.sendCreditRequest(FC.java:528)
org.jgroups.protocols.FC.handleDownMessage(FC.java:365)
org.jgroups.protocols.FC.down(FC.java:300)
org.jgroups.stack.Protocol.receiveDownEvent(Protocol.java:517)
org.jgroups.protocols.FC.receiveDownEvent(FC.java:294)
org.jgroups.stack.Protocol.passDown(Protocol.java:551)
org.jgroups.protocols.FRAG2.down(FRAG2.java:167)
org.jgroups.stack.Protocol.receiveDownEvent(Protocol.java:517)
org.jgroups.stack.Protocol.passDown(Protocol.java:551)
org.jgroups.protocols.pbcast.STATE_TRANSFER.down(STATE_TRANSFER.java:276)
org.jgroups.stack.Protocol.receiveDownEvent(Protocol.java:517)
org.jgroups.stack.ProtocolStack.down(ProtocolStack.java:385)
org.jgroups.JChannel.down(JChannel.java:1175)
org.jgroups.blocks.MessageDispatcher$ProtocolAdapter.down(MessageDispatcher.java:776)
org.jgroups.blocks.MessageDispatcher$ProtocolAdapter.passDown(MessageDispatcher.java:753)
org.jgroups.blocks.RequestCorrelator.sendRequest(RequestCorrelator.java:286)
org.jgroups.blocks.GroupRequest.doExecute(GroupRequest.java:439)
org.jgroups.blocks.GroupRequest.execute(GroupRequest.java:189)
org.jgroups.blocks.MessageDispatcher.castMessage(MessageDispatcher.java:424)
org.jgroups.blocks.RpcDispatcher.callRemoteMethods(RpcDispatcher.java:178)
org.jboss.cache.TreeCache.callRemoteMethods(TreeCache.java:4160)
org.jboss.cache.TreeCache.callRemoteMethods(TreeCache.java:4114)
org.jboss.cache.TreeCache.callRemoteMethods(TreeCache.java:4215)
org.jboss.cache.interceptors.BaseRpcInterceptor.replicateCall(BaseRpcInterceptor.java:110)
org.jboss.cache.interceptors.BaseRpcInterceptor.replicateCall(BaseRpcInterceptor.java:88)
org.jboss.cache.interceptors.ReplicationInterceptor.handleReplicatedMethod(ReplicationInterceptor.java:114)
org.jboss.cache.interceptors.ReplicationInterceptor.invoke(ReplicationInterceptor.java:83)
org.jboss.cache.interceptors.Interceptor.invoke(Interceptor.java:68)
org.jboss.cache.interceptors.TxInterceptor.handleNonTxMethod(TxInterceptor.java:345)
org.jboss.cache.interceptors.TxInterceptor.invoke(TxInterceptor.java:156)
org.jboss.cache.interceptors.Interceptor.invoke(Interceptor.java:68)
org.jboss.cache.interceptors.CacheMgmtInterceptor.invoke(CacheMgmtInterceptor.java:167)
org.jboss.cache.TreeCache.invokeMethod(TreeCache.java:5520)
org.jboss.cache.TreeCache.put(TreeCache.java:3601)
sun.reflect.GeneratedMethodAccessor122.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:585)
org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
org.jboss.system.server.jmx.LazyMBeanServer.invoke(LazyMBeanServer.java:279)
org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210)
$Proxy58.put(Unknown Source)
org.jboss.web.tomcat.tc5.session.JBossCacheWrapper.put(JBossCacheWrapper.java:141)
org.jboss.web.tomcat.tc5.session.JBossCacheService.putSession(JBossCacheService.java:315)
org.jboss.web.tomcat.tc5.session.JBossCacheClusteredSession.processSessionRepl(JBossCacheClusteredSession.java:122)
org.jboss.web.tomcat.tc5.session.JBossCacheManager.processSessionRepl(JBossCacheManager.java:1094)
org.jboss.web.tomcat.tc5.session.JBossCacheManager.storeSession(JBossCacheManager.java:649)
org.jboss.web.tomcat.tc5.session.InstantSnapshotManager.snapshot(InstantSnapshotManager.java:49)
org.jboss.web.tomcat.tc5.session.ClusteredSessionValve.invoke(ClusteredSessionValve.java:98)
org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:74)
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
org.jboss.web.tomcat.tc5.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:153)
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112)
java.lang.Thread.run(Thread.java:595)

Name: IncomingPacketHandler (channel=Tomcat-Cluster)
State: BLOCKED on java.lang.Object@2afbf7 owned by: http-192.168.5.2-8180-4
Total blocked: 85,549 Total waited: 18,813

Stack trace:
org.jgroups.protocols.FC.handleCredit(FC.java:462)
org.jgroups.protocols.FC.up(FC.java:319)
org.jgroups.stack.Protocol.receiveUpEvent(Protocol.java:488)
org.jgroups.stack.Protocol.passUp(Protocol.java:538)
org.jgroups.protocols.pbcast.GMS.up(GMS.java:753)
org.jgroups.stack.Protocol.receiveUpEvent(Protocol.java:488)
org.jgroups.protocols.pbcast.GMS.receiveUpEvent(GMS.java:773)
org.jgroups.stack.Protocol.passUp(Protocol.java:538)
org.jgroups.protocols.pbcast.STABLE.up(STABLE.java:258)
org.jgroups.stack.Protocol.receiveUpEvent(Protocol.java:488)
org.jgroups.stack.Protocol.passUp(Protocol.java:538)
org.jgroups.protocols.UNICAST.handleDataReceived(UNICAST.java:471)
org.jgroups.protocols.UNICAST.up(UNICAST.java:206)
org.jgroups.stack.Protocol.receiveUpEvent(Protocol.java:488)
org.jgroups.stack.Protocol.passUp(Protocol.java:538)
org.jgroups.protocols.pbcast.NAKACK.up(NAKACK.java:569)
org.jgroups.stack.Protocol.receiveUpEvent(Protocol.java:488)
org.jgroups.stack.Protocol.passUp(Protocol.java:538)
org.jgroups.protocols.VERIFY_SUSPECT.up(VERIFY_SUSPECT.java:185)
org.jgroups.stack.Protocol.receiveUpEvent(Protocol.java:488)
org.jgroups.stack.Protocol.passUp(Protocol.java:538)
org.jgroups.protocols.FD.up(FD.java:274)
org.jgroups.stack.Protocol.receiveUpEvent(Protocol.java:488)
org.jgroups.stack.Protocol.passUp(Protocol.java:538)
org.jgroups.protocols.FD_SOCK.up(FD_SOCK.java:303)
org.jgroups.stack.Protocol.receiveUpEvent(Protocol.java:488)
org.jgroups.stack.Protocol.passUp(Protocol.java:538)
org.jgroups.protocols.MERGE2.up(MERGE2.java:163)
org.jgroups.stack.Protocol.receiveUpEvent(Protocol.java:488)
org.jgroups.stack.Protocol.passUp(Protocol.java:538)
org.jgroups.protocols.Discovery.up(Discovery.java:225)
org.jgroups.stack.Protocol.receiveUpEvent(Protocol.java:488)
org.jgroups.stack.Protocol.passUp(Protocol.java:538)
org.jgroups.protocols.TP.handleIncomingMessage(TP.java:918)
org.jgroups.protocols.TP.handleIncomingPacket(TP.java:860)
org.jgroups.protocols.TP.access$200(TP.java:45)
org.jgroups.protocols.TP$IncomingPacketHandler.run(TP.java:1294)
java.lang.Thread.run(Thread.java:595)