RocketMQ Netty NioSocketChannel stuck on read fd 0

[ChangingFond]

Before Creating the Bug Report

• I found a bug, not just asking a question, which should be created in GitHub Discussions.

• I have searched the GitHub Issues and GitHub Discussions of this repository and believe that this is not a duplicate.

• I have confirmed that this bug belongs to the current repository, not other repositories of RocketMQ.

Runtime platform environment

Both CentOS and OpenEuler met

RocketMQ version

RocketMQ 4.9.x

JDK Version

OpenJDK 17.0.2, we use ZGC.

Describe the Bug

We met a extremely strange problem in rocketmq, a netty workerGroup thread hung on sun.nio.ch.SocketDispatcher.read0(workerGroup thread we set 3), then this server's 1/3 another tcp events can't be processed. See details in netty/netty#15746, I wonder if anyone met this.

Then we rollback our production cluster to rocketmq 4.8 & jdk 8, problem is not reproduced.

Environment: rocketmq 4.9.4 on jdk 17.0.2

Steps to Reproduce

we dont't know how to reproduce

What Did You Expect to See?

What Did You See Instead?

Additional Context

No response

[salmaloel657-dotcom]

Thanks for reporting this

…

On Mon, Apr 6, 2026, 10:33 PM ChangingFond ***@***.***> wrote: *ChangingFond* created an issue (apache/rocketmq#10246) <#10246> Before Creating the Bug Report - I found a bug, not just asking a question, which should be created in GitHub Discussions <https://github.com/apache/rocketmq/discussions>. - I have searched the GitHub Issues <https://github.com/apache/rocketmq/issues> and GitHub Discussions <https://github.com/apache/rocketmq/discussions> of this repository and believe that this is not a duplicate. - I have confirmed that this bug belongs to the current repository, not other repositories of RocketMQ. Runtime platform environment CentOS 7.3 RocketMQ version RocketMQ 4.9.4 JDK Version OpenJDK 17.0.2 Describe the Bug We met a strange problem in rocketmq, see details in netty/netty#15746 <netty/netty#15746>, I wonder if anyone met this. Environment: rocketmq 4.9.4 on jdk 17.0.2 Steps to Reproduce we dont't know how to reproduce What Did You Expect to See? - What Did You See Instead? - Additional Context *No response* — Reply to this email directly, view it on GitHub <#10246>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/CABFFMIFO544OHTPDOOAYWD4URZJ5AVCNFSM6AAAAACXO4B6R6VHI2DSMVQWIX3LMV43ASLTON2WKOZUGIYTKMRTGMZTONY> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>