[ https://jira.jboss.org/jira/browse/JGRP-1003?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Bela Ban closed JGRP-1003.
--------------------------
Resolution: Done
> deadlock in TP.send - socket write hangs inside a Lock, preventing other threads to do TP.send()
> ------------------------------------------------------------------------------------------------
>
> Key: JGRP-1003
> URL: https://jira.jboss.org/jira/browse/JGRP-1003
> Project: JGroups
> Issue Type: Bug
> Affects Versions: 2.7
> Environment: Linux (Debian), kernel 2.6.x
> Reporter: Victor N
> Assignee: Bela Ban
> Fix For: 2.8
>
> Attachments: j1__.txt, jgroups_s2.txt, stacktrace.txt
>
>
> I am using JGroups 2.7.0 GA with the typical protocols stack based on TCP (taken from tcp.xml).
> Sometimes it occurs that socket write operation hangs inside TP.send() -- this is not so untypical for blocking I/O approach! -- after that JGroups is not working at all because most of threads are blocked inside TP.send() waiting for that first thread releasing "out_stream_lock". Below is a fragment from my stack trace.
> 1) the thread that hangs in socket write until forever (maybe due to a broken socket or something else); this thread owns "out_stream_lock in TP class":
> "Timer-1,name,IP:port" daemon prio=10 tid=0x084e5c00 nid=0x15f0 runnable [0x211c1000..0x211c2040]
> java.lang.Thread.State: RUNNABLE
> at java.net.SocketOutputStream.socketWrite0(Native Method)
> at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
> at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
> at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
> at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
> - locked <0x43427300> (a java.io.BufferedOutputStream)
> at java.io.DataOutputStream.flush(DataOutputStream.java:106)
> at org.jgroups.blocks.TCPConnectionMap$TCPConnection.doSend(TCPConnectionMap.java:472)
> at org.jgroups.blocks.TCPConnectionMap$TCPConnection._send(TCPConnectionMap.java:453)
> at org.jgroups.blocks.TCPConnectionMap$TCPConnection.send(TCPConnectionMap.java:436)
> at org.jgroups.blocks.TCPConnectionMap$TCPConnection.access$100(TCPConnectionMap.java:341)
> at org.jgroups.blocks.TCPConnectionMap.send(TCPConnectionMap.java:137)
> at org.jgroups.protocols.TCP.send(TCP.java:53)
> at org.jgroups.protocols.BasicTCP.sendToSingleMember(BasicTCP.java:141)
> at org.jgroups.protocols.TP.doSend(TP.java:1105)
> at org.jgroups.protocols.TP.send(TP.java:1088)
> at org.jgroups.protocols.TP.down(TP.java:907)
> at org.jgroups.protocols.Discovery.down(Discovery.java:363)
> at org.jgroups.protocols.MERGE2.down(MERGE2.java:169)
> at org.jgroups.protocols.FD_SOCK.down(FD_SOCK.java:333)
> at org.jgroups.protocols.FD.down(FD.java:327)
> at org.jgroups.protocols.VERIFY_SUSPECT.down(VERIFY_SUSPECT.java:72)
> at org.jgroups.protocols.BARRIER.down(BARRIER.java:96)
> at org.jgroups.protocols.pbcast.NAKACK.retransmit(NAKACK.java:1530)
> at org.jgroups.protocols.pbcast.NAKACK.retransmit(NAKACK.java:1476)
> at org.jgroups.stack.Retransmitter$Task.run(Retransmitter.java:207)
> at org.jgroups.util.TimeScheduler$TaskWrapper.run(TimeScheduler.java:218)
> at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
> at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
> at java.util.concurrent.FutureTask.run(FutureTask.java:138)
> at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:98)
> at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:207)
> at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
> at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
> at java.lang.Thread.run(Thread.java:619)
> Locked ownable synchronizers:
> - <0x2b5522e0> (a java.util.concurrent.locks.ReentrantLock$NonfairSync)
> - <0x2b5550f8> (a java.util.concurrent.locks.ReentrantLock$NonfairSync)
> - <0x434273f0> (a java.util.concurrent.locks.ReentrantLock$NonfairSync)
> 2) and there are many threads like this blocked "on out_stream_lock.lock()" call inside TP class:
> "Connection.Receiver [ip:port - ip:port],name,ip:port" prio=10 tid=0x020dc000 nid=0x1fab waiting on condition [0x1365f000..0x1365ffc0]
> java.lang.Thread.State: WAITING (parking)
> at sun.misc.Unsafe.park(Native Method)
> - parking to wait for <0x2b5550f8> (a java.util.concurrent.locks.ReentrantLock$NonfairSync)
> at java.util.concurrent.locks.LockSupport.park(LockSupport.java:158)
> at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:747)
> at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:778)
> at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1114)
> at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:186)
> at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:262)
> at org.jgroups.protocols.TP.send(TP.java:1082)
> at org.jgroups.protocols.TP.down(TP.java:907)
> at org.jgroups.protocols.Discovery.up(Discovery.java:274)
> at org.jgroups.protocols.TP.passMessageUp(TP.java:995)
> at org.jgroups.protocols.TP.access$100(TP.java:52)
> at org.jgroups.protocols.TP$IncomingPacket.handleMyMessage(TP.java:1451)
> at org.jgroups.protocols.TP$IncomingPacket.run(TP.java:1427)
> at java.util.concurrent.ThreadPoolExecutor$CallerRunsPolicy.rejectedExecution(ThreadPoolExecutor.java:1738)
> at org.jgroups.util.ShutdownRejectedExecutionHandler.rejectedExecution(ShutdownRejectedExecutionHandler.java:34)
> at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:767)
> at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:658)
> at org.jgroups.protocols.TP.dispatchToThreadPool(TP.java:1061)
> at org.jgroups.protocols.TP.receive(TP.java:1038)
> at org.jgroups.protocols.BasicTCP.receive(BasicTCP.java:180)
> at org.jgroups.blocks.TCPConnectionMap$TCPConnection$ConnectionPeerReceiver.run(TCPConnectionMap.java:553)
> at java.lang.Thread.run(Thread.java:619)
>
> Locked ownable synchronizers:
> - None
> (Since all threads from JGroups' ThreadPool are locked, you can see "rejectedExecution" in the last stack trace).
> Maybe we could implement some solution for TCP (blocking I/O)? Maybe it is possible to release the lock before socket write?
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