0001719: Thread race when com.caucho.quercus.env.DefinitionState

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Category

Severity

Reproducibility

Date Submitted

Last Update

0001719

[Quercus]

crash

always

04-27-07 08:44

04-29-07 02:53

Reporter

salishev

View Status

public

Assigned To

nam

Priority

normal

Resolution

fixed

Status

closed

Product Version

3.1.1

Summary

0001719: Thread race when com.caucho.quercus.env.DefinitionState

Description

I've checked with latest resin-3.1.s070425 snapshot

The following exception is always thrown when requesting 64K pages from 2 or more threads simultanously

[19:31:33.820] java.util.ConcurrentModificationException
[19:31:33.820] at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
[19:31:33.820] at java.util.HashMap$EntryIterator.next(HashMap.java:833)
[19:31:33.820] at java.util.HashMap$EntryIterator.next(HashMap.java:831)
[19:31:33.820] at java.util.HashMap.putAll(HashMap.java:523)
[19:31:33.820] at com.caucho.quercus.env.DefinitionState.<init>(DefinitionState.java:98)
[19:31:33.820] at com.caucho.quercus.env.DefinitionState.copy(DefinitionState.java:357)
[19:31:33.820] at com.caucho.quercus.Quercus.putDefinitionCache(Quercus.java:673)
[19:31:33.820] at com.caucho.quercus.env.Env.importPage(Env.java:3317)
[19:31:33.820] at com.caucho.quercus.env.Env.include(Env.java:3295)
[19:31:33.820] at com.caucho.quercus.expr.IncludeExpr.eval(IncludeExpr.java:86)
[19:31:33.820] at com.caucho.quercus.program.ExprStatement.execute(ExprStatement.java:64)
[19:31:33.820] at com.caucho.quercus.program.BlockStatement.execute(BlockStatement.java:99)
[19:31:33.820] at com.caucho.quercus.program.Function.callImpl(Function.java:316)
[19:31:33.820] at com.caucho.quercus.program.Function.call(Function.java:264)
[19:31:33.820] at com.caucho.quercus.expr.FunctionExpr.evalImpl(FunctionExpr.java:180)
[19:31:33.820] at com.caucho.quercus.expr.FunctionExpr.eval(FunctionExpr.java:125)
[19:31:33.820] at com.caucho.quercus.program.ExprStatement.execute(ExprStatement.java:64)
[19:31:33.820] at com.caucho.quercus.program.BlockStatement.execute(BlockStatement.java:99)
[19:31:33.820] at com.caucho.quercus.program.QuercusProgram.execute(QuercusProgram.java:239)
[19:31:33.820] at com.caucho.quercus.page.InterpretedPage.execute(InterpretedPage.java:61)
[19:31:33.820] at com.caucho.quercus.page.QuercusPage.executeTop(QuercusPage.java:115)
[19:31:33.820] at com.caucho.quercus.servlet.ResinQuercusServlet.service(ResinQuercusServlet.java:125)
[19:31:33.820] at com.caucho.quercus.servlet.QuercusServlet.service(QuercusServlet.java:341)
[19:31:33.820] at javax.servlet.http.HttpServlet.service(HttpServlet.java:92)
[19:31:33.820] at com.caucho.server.dispatch.ServletFilterChain.doFilter(ServletFilterChain.java:103)
[19:31:33.820] at com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:175)
[19:31:33.820] at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:240)
[19:31:33.820] at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:263)
[19:31:33.820] at com.caucho.server.port.TcpConnection.run(TcpConnection.java:477)
[19:31:33.820] at com.caucho.util.ThreadPool$Item.runTasks(ThreadPool.java:600)
[19:31:33.820] at com.caucho.util.ThreadPool$Item.run(ThreadPool.java:522)
[19:31:33.820] at java.lang.Thread.run(Thread.java:619)

Additional Information

Can't provide the test case as it's proprietary software.

It uses DokuWiki as a backend and creates an exhaustive multi-threaded request stream through http with page size of 64K.

Synchronizing access to com.caucho.quercus.env.DefinitionState solves the problem.

Attached Files

Relationships

Notes
(0001873) salishev 04-28-07 04:10	The root cause is incorrect implementation of copyLazy. It supposes the original is immutable which is not true. So it's possible to concurrently mutate the original while creating non lazy copy in copy/copyOnWrite method. So copyLazy should ensure the original is lazy.

(0001874) salishev 04-28-07 04:13	Also Method findFunction mutates the object without creating the lazy copy.

(0001877) nam 04-29-07 02:53	Thanks for the detailed report. DefinitionState.findFunction() was missing the copyOnWrite()'s, thus allowing a lazy copy to modify the original's HashMap.

Issue History
Date Modified	Username	Field	Change
04-27-07 08:44	salishev	New Issue
04-28-07 04:10	salishev	Note Added: 0001873
04-28-07 04:13	salishev	Note Added: 0001874
04-29-07 02:49	nam	Status	new => assigned
04-29-07 02:49	nam	Assigned To	=> nam
04-29-07 02:53	nam	Status	assigned => closed
04-29-07 02:53	nam	Note Added: 0001877
04-29-07 02:53	nam	Resolution	open => fixed
04-29-07 02:53	nam	Fixed in Version	=> 3.1.1

Mantis 1.0.0rc3[^]

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