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https://issues.apache.org/jira/browse/AMQNET-727?focusedWorklogId=917623&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-917623
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ASF GitHub Bot logged work on AMQNET-727:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 04/May/24 11:52
Start Date: 04/May/24 11:52
Worklog Time Spent: 10m
Work Description: AndyDeMauriceGEDigital commented on PR #37:
URL:
https://github.com/apache/activemq-nms-openwire/pull/37#issuecomment-2094135906
@chirino Can you please review this change?
Issue Time Tracking
-------------------
Worklog Id: (was: 917623)
Time Spent: 1h (was: 50m)
> Thread sync error with MessageConsumer.pendingAck
> -------------------------------------------------
>
> Key: AMQNET-727
> URL: https://issues.apache.org/jira/browse/AMQNET-727
> Project: ActiveMQ .Net
> Issue Type: Bug
> Components: OpenWire
> Affects Versions: 1.8.0
> Reporter: Andy DeMaurice
> Priority: Major
> Time Spent: 1h
> Remaining Estimate: 0h
>
> pendingAck is accessed by multiple threads; in most places where it is
> written, it is done along with accessing *deliveredMessages*, so it is
> written within a *lock(this.deliveredMessages)* block.
> However, this call stack shows where pendingAck gets assigned to a new
> MessageAck object, NOT within the lock... and it is subject to being
> overwritten by another thread (usually the other thread is in
> MessageConsumer.Acknowledge() :
>
> Apache.NMS.ActiveMQ.MessageConsumer.AckLater(Apache.NMS.ActiveMQ.Commands.MessageDispatch,
> Apache.NMS.ActiveMQ.AckType)
> Apache.NMS.ActiveMQ.MessageConsumer.AfterMessageIsConsumed(Apache.NMS.ActiveMQ.Commands.MessageDispatch,
> Boolean)
> Apache.NMS.ActiveMQ.MessageConsumer.Dispatch(Apache.NMS.ActiveMQ.Commands.MessageDispatch)
> Apache.NMS.ActiveMQ.SessionExecutor.Dispatch(Apache.NMS.ActiveMQ.Commands.MessageDispatch)
> Apache.NMS.ActiveMQ.SessionExecutor.Iterate()
> Apache.NMS.ActiveMQ.Threads.DedicatedTaskRunner.Run()
>
> The usual symptom I see is a NullReferenceException in this section of code
> within AckLater; because pendingAck has been set to null by another thread:
>
> if(oldPendingAck == null)
> {
> pendingAck.FirstMessageId = pendingAck.LastMessageId;
> }
> else if(oldPendingAck.AckType == pendingAck.AckType)
> {
> pendingAck.FirstMessageId = oldPendingAck.FirstMessageId;
> }
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