[rabbitmq-discuss] Java client 2.1.0 deadlock

[Rob Harrop]

Anton,

I just pushed a fix for this issue on branch bug23360:

http://hg.rabbitmq.com/rabbitmq-java-client/rev/83a89cdc53aa

Let me know if this works for you.

Regards,

Rob

On 12 Oct 2010, at 15:03, mabrek wrote:

> Hello.
> I've got reproducible deadlock while working with java client 2.1.0.
> 
> Steps to follow:
> 1) create connection
> 2) create several threads that use single connection from step 1. Each
> thread does:
> 2.1) create channel
> 2.2) consumes from non-existing queue
> 3) run all threads in parallel.
> It will hang up.
> 
> One thread holds lock on ChannelManager:
> "pool-1-thread-3" prio=10 tid=0x00007f74640e2000 nid=0x4667 in
> Object.wait() [0x00007f7463ffe000]
>   java.lang.Thread.State: WAITING (on object monitor)
> 	at java.lang.Object.wait(Native Method)
> 	- waiting on <0x00007f747339bbe8> (a
> com.rabbitmq.utility.BlockingValueOrException)
> 	at java.lang.Object.wait(Object.java:485)
> 	at com.rabbitmq.utility.BlockingCell.get(BlockingCell.java:64)
> 	- locked <0x00007f747339bbe8> (a com.rabbitmq.utility.BlockingValueOrException)
> 	at com.rabbitmq.utility.BlockingCell.uninterruptibleGet(BlockingCell.java:103)
> 	- locked <0x00007f747339bbe8> (a com.rabbitmq.utility.BlockingValueOrException)
> 	at com.rabbitmq.utility.BlockingValueOrException.uninterruptibleGetValue(BlockingValueOrException.java:47)
> 	at com.rabbitmq.client.impl.AMQChannel$BlockingRpcContinuation.getReply(AMQChannel.java:342)
> 	at com.rabbitmq.client.impl.AMQChannel.rpc(AMQChannel.java:215)
> 	at com.rabbitmq.client.impl.AMQChannel.exnWrappingRpc(AMQChannel.java:139)
> 	at com.rabbitmq.client.impl.ChannelN.open(ChannelN.java:125)
> 	at com.rabbitmq.client.impl.ChannelManager.createChannelInternal(ChannelManager.java:121)
> 	- locked <0x00007f7473af80c8> (a com.rabbitmq.client.impl.ChannelManager)
> 	at com.rabbitmq.client.impl.ChannelManager.createChannel(ChannelManager.java:100)
> 	- locked <0x00007f7473af80c8> (a com.rabbitmq.client.impl.ChannelManager)
> 	at com.rabbitmq.client.impl.AMQConnection.createChannel(AMQConnection.java:382)
> 
> AMQP connection waits for this lock to handle Channel.Close(NOT_FOUND)
> "AMQP Connection localhost:5672" prio=10 tid=0x00007f7464287800
> nid=0x4675 waiting for monitor entry [0x00007f74631f0000]
>   java.lang.Thread.State: BLOCKED (on object monitor)
> 	at com.rabbitmq.client.impl.ChannelManager.disconnectChannel(ChannelManager.java:135)
> 	- waiting to lock <0x00007f7473af80c8> (a
> com.rabbitmq.client.impl.ChannelManager)
> 	at com.rabbitmq.client.impl.AMQConnection.disconnectChannel(AMQConnection.java:130)
> 	at com.rabbitmq.client.impl.ChannelN.releaseChannelNumber(ChannelN.java:205)
> 	at com.rabbitmq.client.impl.ChannelN.processAsync(ChannelN.java:229)
> 	at com.rabbitmq.client.impl.AMQChannel.handleCompleteInboundCommand(AMQChannel.java:165)
> 	at com.rabbitmq.client.impl.AMQChannel.handleFrame(AMQChannel.java:110)
> 	at com.rabbitmq.client.impl.AMQConnection$MainLoop.run(AMQConnection.java:434)
>   Locked ownable synchronizers:
> 	- None
> 
> All other threads wait for this lock:
> "pool-6-thread-1" prio=10 tid=0x00007f74642d4800 nid=0x4698 waiting
> for monitor entry [0x00007f7460ecd000]
>   java.lang.Thread.State: BLOCKED (on object monitor)
> 	at com.rabbitmq.client.impl.ChannelManager.createChannel(ChannelManager.java:96)
> 	- waiting to lock <0x00007f7473af80c8> (a
> com.rabbitmq.client.impl.ChannelManager)
> 	at com.rabbitmq.client.impl.AMQConnection.createChannel(AMQConnection.java:382)
> 
> It looks like something was done around this issue at branch bug22064,
> but it haven't merged into default yet and it's quite old. Do you have
> any plans to use more fine grained locking in ChannelManager?
> 
> Regards,
> Anton Lebedevich.
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