Fixes are available
9.0.0.10: WebSphere Application Server traditional V9.0 Fix Pack 10
8.5.5.15: WebSphere Application Server V8.5.5 Fix Pack 15
9.0.0.11: WebSphere Application Server traditional V9.0 Fix Pack 11
9.0.5.0: WebSphere Application Server traditional Version 9.0.5 Refresh Pack
9.0.5.1: WebSphere Application Server traditional Version 9.0.5 Fix Pack 1
9.0.5.2: WebSphere Application Server traditional Version 9.0.5 Fix Pack 2
8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
9.0.5.3: WebSphere Application Server traditional Version 9.0.5 Fix Pack 3
8.5.5.20: WebSphere Application Server V8.5.5.20
8.5.5.18: WebSphere Application Server V8.5.5 Fix Pack 18
8.5.5.19: WebSphere Application Server V8.5.5 Fix Pack 19
8.5.5.16: WebSphere Application Server V8.5.5 Fix Pack 16
8.5.5.21: WebSphere Application Server V8.5.5.21
APAR status
Closed as program error.
Error description
There exists the potential for deadlock with the ORM XML processing function in an environment with multiple threads. Xerces calls Thread.currentThread().getContextClassloader() during its execution to construct the SAXParser (via ObjectFactory.createObject()). This means that within the call to Xerces, a ClassLoader lock will be attempted on the Thread's ContextClassLoader. If there is already a lock with a ClassLoader higher in the heirarchy, and another thread with a lock on the same ContextClassLoader that is waiting to acquire a lock on a higher level ClassLoader, then a deadlock will occur. This issue was revealed in a Liberty build break: RTC238000, but we maintain common code with tWAS.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of IBM WebSphere Application * * Server - Java Persistence APA - * * JPA 2.0 & OpenJPA * **************************************************************** * PROBLEM DESCRIPTION: There exists the potential for * * deadlock with the ORM XMLprocessing * * function in an environment with * * multiple threads. * **************************************************************** * RECOMMENDATION: * **************************************************************** There exists the potential for deadlock with the ORM XMLprocessing function in an environment with multiple threads. Xerces calls Thread.currentThread().getContextClassloader() during its execution to construct the SAXParser (via ObjectFactory.createObject()). This means that within the call to Xerces, a ClassLoader lock will be attempted on the Thread's ContextClassLoader. If there is already a lock with a ClassLoader higher in the heirarchy, and another thread with a lock on the same ContextClassLoader that is waiting to acquire a lock on a higher level ClassLoader, then a deadlock will occur. Exception: 00000036 SystemOut O | DEADLOCK DETECTED BY THE JVM, thread details: 00000036 SystemOut O LargeThreadPool-thread-23 64 BLOCKED java.lang.ClassLoader.loadClass(ClassLoader.java:763) com.ibm.ws.classloading.internal.UnifiedClassLoader.loadClass0(U nifiedClassLoader.java:108) com.ibm.ws.classloading.internal.UnifiedClassLoader$Delegation.l oadClass(UnifiedClassLoader.java:79) com.ibm.ws.classloading.internal.UnifiedClassLoader.loadClass(Un ifiedClassLoader.java:103) com.ibm.ws.classloading.internal.ThreadContextClassLoader.loadCl ass(ThreadContextClassLoader.java:112) java.lang.ClassLoader.loadClass(ClassLoader.java:741)
Problem conclusion
The fix for this APAR changes the OpenJPA implementation and involves an update to the thirdparty source. See https://issues.apache.org/jira/browse/OPENJPA-1993 This fix is currently targeted for WebSphere Application Server 9.0.0.10, 8.5.5.15, and WebSphere Liberty 18.0.0.3. Please refer to the Recommended Updates page for delivery information: http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
Temporary fix
Comments
APAR Information
APAR number
PH01768
Reported component name
WEBSPHERE APP S
Reported component ID
5724J0800
Reported release
900
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2018-08-16
Closed date
2018-08-17
Last modified date
2018-08-17
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
WEBSPHERE APP S
Fixed component ID
5724J0800
Applicable component levels
R850 PSY
UP
R900 PSY
UP
Document Information
Modified date:
28 April 2022