0003620: _attrGetMap instance variable in IntrospectionMBean class should be synchronized

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Category

Severity

Reproducibility

Date Submitted

Last Update

0003620

[Resin]

major

sometimes

08-03-09 12:04

08-12-09 16:33

Reporter

ebarlas

View Status

public

Assigned To

ferg

Priority

normal

Resolution

fixed

Platform

Status

closed

Projection

none

OS Version

ETA

none

Fixed in Version

4.0.2

Product Version

3.0.21

Product Build

Summary

0003620: _attrGetMap instance variable in IntrospectionMBean class should be synchronized

Description

The _attrGetMap field in IntrospectionMBean class should be synchronized, as the same IntrospectionMBean can be accessed by multiple threads. This can result in corruption of the HashMap. In fact, two threads may resize the HashMap at the same time on a put, which can cause a cycle in a linked list of entries in the HashMap. If this occurs, a get on the map for a key that does not exist may enter an infinite loop. We have reproduced this behavior. See excerpt from stack trace below. This thread has been in this state for about 3 days now.

"resin-tcp-connection-lt2fe5.qai.expertcity.com:8080-27" daemon prio=10 tid=0x000000004461c400 nid=0x3fb0 runnable [0x0000000042012000..0x0000000042013d90]
   java.lang.Thread.State: RUNNABLE
        at java.util.HashMap.get(HashMap.java:303)
        at com.caucho.jmx.IntrospectionMBean.getGetMethod(IntrospectionMBean.java:209)
        at com.caucho.jmx.IntrospectionMBean.getAttribute(IntrospectionMBean.java:115)
        at com.caucho.jmx.MBeanWrapper.getAttribute(MBeanWrapper.java:169)
        at com.caucho.jmx.AbstractMBeanServer.getAttribute(AbstractMBeanServer.java:654)
        at
...
org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:875)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:807)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:571)
        at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:501)

Steps To Reproduce

Additional Information

Attached Files

Relationships

Notes
(0004112) ebarlas 08-03-09 12:14	The simplest fix would be to use a Hashtable instead of a HashMap

Issue History
Date Modified	Username	Field	Change
08-03-09 12:04	ebarlas	New Issue
08-03-09 12:14	ebarlas	Note Added: 0004112
08-03-09 12:15	ebarlas	Issue Monitored: ebarlas
08-12-09 16:33	ferg	Assigned To	=> ferg
08-12-09 16:33	ferg	Status	new => closed
08-12-09 16:33	ferg	Resolution	open => fixed
08-12-09 16:33	ferg	Fixed in Version	=> 4.0.2

Mantis 1.0.0rc3[^]

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