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Bug 316405

Summary:

Thread deadlock between KernelBundleClassLoader and ChainedClassloader during classloading

Product:

[RT] Virgo

Reporter:

blahb Mising name <dyfxos8d>

Component:

unknown

Assignee:

Project Inbox <virgo-inbox>

Status:

CLOSED FIXED

QA Contact:

Severity:

critical

Priority:

CC:

dyfxos8d, glyn.normington

Version:

unspecified

Target Milestone:

---

Hardware:

All

OS:

All

Whiteboard:

Attachments:

Description	Flags
Stack trace dump.	dyfxos8d: review?

Description blahb Mising name

2010-06-09 22:01:57 EDT

Build Identifier: 2.0.2.RELEASE

Within 10-15 minutes of running our webapp bundle under significant load, we experience a thread deadlock which makes the process unresponsive to any HTTP requests or JMX connections. The deadlock seems to be in platform classloading code before our bundle code has been placed on the stack for responding to the HTTP request.

This is repeatable under SpringSource DM Server 2.0.2.RELEASE, and I've logged it there, but it appears that this issue tracker may be replacing that one; I'm not sure where to log it.  Sorry.

Attached is the thread deadlock information from the automatically generated dumps.

Reproducible: Always

Steps to Reproduce:
1. Deploy webapp bundle.
2. Load it heavily with traffic.
3. Wait for thread deadlock in classloaders.

Comment 1 blahb Mising name

2010-06-09 22:05:01 EDT

Created attachment 171600 [details]
Stack trace dump.

Comment 2 blahb Mising name

2010-06-09 22:19:11 EDT

Cross-reference to bug in SpringSource issue tracker:
https://issuetracker.springsource.com/browse/DMS-2651

Comment 3 Glyn Normington

2010-06-10 10:31:48 EDT

The deadlock is caused by an alien call in ChainedClassLoader. The fix is to remove synchronisation from this class. The class is immutable and therefore thread safe without synchronisation.

This fix should be included in 2.1.0.M1.