[SNMP4J] thread lock in org.snmp4j.mp.MPv3.prepareResponseMessage

[shangtang wei]

Hello, everyone,





Snmp4j version 1.11.2.

We have 50 threads to process inform msg. we encountered many times this
snmp stack thread state.  Can someone give me some advice?

49 threads stack trace:

"DispatcherPool.5" prio=3 tid=0x02f59800 nid=0x112 waiting for monitor entry
[0x161ef000..0x161efbf0]

    java.lang.Thread.State: BLOCKED (on object monitor)

               at
org.snmp4j.Snmp$NotificationDispatcher.processPdu(Snmp.java:1825)

               - waiting to lock <0x60b6fff8> (a
org.snmp4j.Snmp$NotificationDispatcher)

               at org.snmp4j.Snmp.fireProcessPdu(Snmp.java:1430)

               at org.snmp4j.Snmp.processPdu(Snmp.java:1288)

               at
org.snmp4j.MessageDispatcherImpl.fireProcessPdu(MessageDispatcherImpl.java:616)

               at
org.snmp4j.MessageDispatcherImpl.dispatchMessage(MessageDispatcherImpl.java:287)

               at
org.snmp4j.MessageDispatcherImpl.processMessage(MessageDispatcherImpl.java:347)

               at
org.snmp4j.util.MultiThreadedMessageDispatcher$MessageTask.run(MultiThreadedMessageDispatcher.java:209)

               at
org.snmp4j.util.ThreadPool$TaskManager.run(ThreadPool.java:239)

               - locked <0x56e5e980> (a
org.snmp4j.util.ThreadPool$TaskManager)

1 thread stack trace:

"DispatcherPool.10" prio=3 tid=0x02dfc800 nid=0x117 runnable
[0x1605f000..0x1605fa70]

    java.lang.Thread.State: RUNNABLE

               at java.util.WeakHashMap.get(Unknown Source)

               at org.snmp4j.mp.MPv3$Cache.popEntry(MPv3.java:495)

               - locked <0x565be9c0> (a org.snmp4j.mp.MPv3$Cache)

               at org.snmp4j.mp.MPv3.prepareResponseMessage(MPv3.java:810)

               at
org.snmp4j.MessageDispatcherImpl.returnResponsePdu(MessageDispatcherImpl.java:553)

               at
org.snmp4j.util.MultiThreadedMessageDispatcher.returnResponsePdu(MultiThreadedMessageDispatcher.java:162)

               at
org.snmp4j.Snmp$NotificationDispatcher.sendInformResponse(Snmp.java:1858)

               at
org.snmp4j.Snmp$NotificationDispatcher.processPdu(Snmp.java:1831)

               - locked <0x60b6fff8> (a
org.snmp4j.Snmp$NotificationDispatcher)

               at org.snmp4j.Snmp.fireProcessPdu(Snmp.java:1430)

               at org.snmp4j.Snmp.processPdu(Snmp.java:1288)

               at
org.snmp4j.MessageDispatcherImpl.fireProcessPdu(MessageDispatcherImpl.java:616)

               at
org.snmp4j.MessageDispatcherImpl.dispatchMessage(MessageDispatcherImpl.java:287)

               at
org.snmp4j.MessageDispatcherImpl.processMessage(MessageDispatcherImpl.java:347)

               at
org.snmp4j.util.MultiThreadedMessageDispatcher$MessageTask.run(MultiThreadedMessageDispatcher.java:209)

               at
org.snmp4j.util.ThreadPool$TaskManager.run(ThreadPool.java:239)

               - locked <0x568fdb20> (a
org.snmp4j.util.ThreadPool$TaskManager)



[DispatcherPool.44] Aug 21, 2011 10:16:25 PM org.snmp4j.log.JavaLogAdapter
log

FINE: Fire process PDU event: CommandResponderEvent



[DispatcherPool.44] Aug 21, 2011 10:16:28 PM org.snmp4j.log.JavaLogAdapter
log

FINE: Sending message to 27.184.161.225/34248 with





Regards

-shangtang