Bug 1196228

Summary:	[GSS] (6.4.z) ConsoleAppenders can deadlock if included in application log4j configs
Product:	[JBoss] JBoss Enterprise Application Platform 6	Reporter:	Aaron Ogburn <aogburn>
Component:	Logging	Assignee:	Lin Gao <lgao>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Nikoleta Hlavickova <nziakova>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	6.4.0	CC:	bbaranow, bmaxwell, cdewolf, chaowan, csutherl, jawilson, joallen, lgao, sfikes
Target Milestone:	CR1
Target Release:	EAP 6.4.2
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
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Last Closed:		Type:	Bug
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	1211155, 1219165

Description Aaron Ogburn 2015-02-25 14:24:18 UTC

Description of problem:

While the use of ConsoleAppender in Log4J application logging configurations is discouraged, JBoss could probably do a better job of managing its use.

Currently it's possible to encounter a deadlock if thread A invokes System.out.println() and thread B invokes Logger.info(). Thread A will get the lock on System.out (a java.io.PrintWriter), but then thread B will get the lock on the org.apache.log4j.ConsoleAppender. Then each thread is waiting on the other's lock.

Comment 1 Aaron Ogburn 2015-02-25 14:25:27 UTC

Work around is to not use ConsoleAppenders in app log4js or them in async appender/handlers.

Comment 2 James Perkins 2015-02-25 18:32:40 UTC

We'd have to fork the ConsoleAppender to make this work properly since each append invocation uses System.xxx.write(). We'd need to update it to capture System.out and System.err in a static variable to ensure it would work correctly.

Comment 4 Aaron Ogburn 2015-03-06 15:36:05 UTC

If we don't want to go for a ConsoleAppender fork to resolve the deadlock, perhaps we can at least add a warn to notify that a deadlock is likely with the application level ConsoleAppender?

Comment 12 baranowb 2015-04-13 07:52:59 UTC

PR https://github.com/jboss-logging/log4j-jboss-logmanager/pull/10

MERGED.

Comment 19 Nikoleta Hlavickova 2015-06-23 10:54:52 UTC

Verified with EAP 6.4.2.CP.CR1 using attached reproducer.

Comment 20 Petr Penicka 2017-01-17 10:17:07 UTC

Retroactively bulk-closing issues from released EAP 6.4 cumulative patches.

Comment 21 Petr Penicka 2017-01-17 10:17:13 UTC

Retroactively bulk-closing issues from released EAP 6.4 cumulative patches.