Bug 54497

Summary:	RuntimeException in WebappClassLoader.checkThreadLocalMapForLeaks() causes LifecycleException
Product:	Tomcat 8	Reporter:	Konstantin Kolinko <knst.kolinko>
Component:	Catalina	Assignee:	Tomcat Developers Mailing List <dev>
Status:	RESOLVED FIXED
Severity:	normal	CC:	sktg84
Priority:	P2
Version:	8.0.x-trunk
Target Milestone:	----
Hardware:	PC
OS:	Windows XP

Description Konstantin Kolinko 2013-01-25 23:16:17 UTC

Observed this when testing Tomcat trunk at r1438747, at WinXP 32-bit, JDK 7u11.
(running TestWsWebSocketContainer with APR, Tomcat-Native 1.1.26 RC)

There occurred an NPE in WebappClassLoader.checkThreadLocalMapForLeaks(). It was uncaught and caused LifecycleException and ultimately a failure to stop Tomcat.

===============
In stderr:
SEVERE: A child container failed during stop
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to stop component [StandardEngine[Tomcat].StandardHost[localhost].StandardContext[]]
	at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:252)
	at java.util.concurrent.FutureTask.get(FutureTask.java:111)
	at org.apache.catalina.core.ContainerBase.stopInternal(ContainerBase.java:974)
	at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:232)
	at org.apache.catalina.core.ContainerBase$StopChild.call(ContainerBase.java:1404)
	at org.apache.catalina.core.ContainerBase$StopChild.call(ContainerBase.java:1393)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
	at java.util.concurrent.FutureTask.run(FutureTask.java:166)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
	at java.lang.Thread.run(Thread.java:722)
Caused by: org.apache.catalina.LifecycleException: Failed to stop component [StandardEngine[Tomcat].StandardHost[localhost].StandardContext[]]
	at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:236)
	... 7 more
Caused by: org.apache.catalina.LifecycleException: Failed to stop component [WebappLoader[]]
	at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:236)
	at org.apache.catalina.core.StandardContext.stopInternal(StandardContext.java:5365)
	at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:232)
	... 7 more
Caused by: java.lang.NullPointerException
	at sun.reflect.UnsafeFieldAccessorImpl.ensureObj(UnsafeFieldAccessorImpl.java:54)
	at sun.reflect.UnsafeObjectFieldAccessorImpl.get(UnsafeObjectFieldAccessorImpl.java:36)
	at java.lang.reflect.Field.get(Field.java:372)
	at org.apache.catalina.loader.WebappClassLoader.checkThreadLocalMapForLeaks(WebappClassLoader.java:2247)
	at org.apache.catalina.loader.WebappClassLoader.checkThreadLocalsForLeaks(WebappClassLoader.java:2188)
	at org.apache.catalina.loader.WebappClassLoader.clearReferences(WebappClassLoader.java:1731)
	at org.apache.catalina.loader.WebappClassLoader.stop(WebappClassLoader.java:1641)
	at org.apache.catalina.loader.WebappLoader.stopInternal(WebappLoader.java:491)
	at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:232)
	... 9 more
===============
In testcase:
Testcase: testSmallTextBufferClientTextMessage took 2,328 sec
	Caused an ERROR
Failed to stop component [StandardServer[-1]]
org.apache.catalina.LifecycleException: Failed to stop component [StandardServer[-1]]
	at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:236)
	at org.apache.catalina.startup.Tomcat.stop(Tomcat.java:336)
	at org.apache.catalina.startup.TomcatBaseTest.tearDown(TomcatBaseTest.java:163)
Caused by: org.apache.catalina.LifecycleException: Failed to stop component [StandardService[Tomcat]]
	at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:236)
	at org.apache.catalina.core.StandardServer.stopInternal(StandardServer.java:766)
	at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:232)
Caused by: org.apache.catalina.LifecycleException: Failed to stop component [StandardEngine[Tomcat]]
	at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:236)
	at org.apache.catalina.core.StandardService.stopInternal(StandardService.java:501)
	at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:232)
Caused by: org.apache.catalina.LifecycleException: A child container failed during stop
	at org.apache.catalina.core.ContainerBase.stopInternal(ContainerBase.java:981)
	at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:232)
===============

Thoughts:
1. We should catch throwables in those checkFor**Leaks methods. It should not cause a "failed to stop component" failure.
2. In that method there are many calls to "table[j]". The array member should be evaluated only once, so that it does not become null unexpectedly.

Comment 1 Mark Thomas 2013-02-01 12:41:49 UTC

Looks like I fixed the multiple references to table[j] and committed it accidentally as part of r1440622. I'll look at adding the try/catch.

Comment 2 Mark Thomas 2013-02-01 12:52:21 UTC

Fixed in trunk and 7.0.x. Will be in 7.0.26 onwards.

Comment 3 Chuck Caldarale 2013-02-01 14:19:22 UTC

(In reply to comment #2)
> Fixed in trunk and 7.0.x. Will be in 7.0.26 onwards.

That would be 7.0.36 onwards.

Comment 4 Violeta Georgieva 2013-04-17 04:53:58 UTC

*** Bug 54831 has been marked as a duplicate of this bug. ***