JR51504: JAVASCRIPT LOOP DETECTION DOES NOT CATCH LOOPS THAT SPEND MOST OF THE TIME IN JAVA CODE

8.0.1.2-WS-BPM-IFJR51504
8.5.0.1-WS-BPM-IFJR51504
8.0.1.3-WS-BPM-IFJR51504
8.0.1.1-WS-BPM-IFJR51504
Version 8.5 Refresh Pack 6 for the IBM Business Process Manager products
Version 8.5.0 Fix Pack 2 for the IBM Business Process Manager products

APAR status

• Closed as program error.

Error description

• With APAR JR48395, a capability was introduced that helps you
  detect loops in JavaScript. However, JR48395 does not detect
  loops when a JavaScript issues Java calls in a loop and most of
  the execution time is spent inside the Java code. In the case
  for BPM, this where a managed asset (a JAR) has a loop in that
  code path which prevents it from returning back to the BPM
  engine for processing.
  
  .
  [10/22/14 16:05:42:466 EDT] 0000008e ThreadMonitor W
  WSVR0605W: Thread
   "WorkManager.bpm-em-workmanager : 14148" (00008338) has been
  active for
   668295 milliseconds and may be hung.  There is/are 1 thread(s)
  in total
   in the server that may be hung.
   at java.util.HashMap.findNonNullKeyEntry(HashMap.java:601)
   at java.util.HashMap.getEntry(HashMap.java:585)
   at java.util.HashMap.get(HashMap.java:571)
   at
  org.mozilla.javascript.JavaMembers.lookupClass(JavaMembers.java:
  833)
   at
  org.mozilla.javascript.NativeJavaClass.initMembers(NativeJavaCla
  ss.java:84)
   at
  org.mozilla.javascript.NativeJavaClass.<init>(NativeJavaClass.ja
  va:78)
   at
  org.mozilla.javascript.NativeJavaPackage.getPkgProperty(NativeJa
  vaPackage.java:164)
   at
  org.mozilla.javascript.NativeJavaPackage.get(NativeJavaPackage.j
  ava:114)
   at
  org.mozilla.javascript.ScriptableObject.getProperty(ScriptableOb
  ject.java:1617)
   at
  org.mozilla.javascript.ScriptRuntime.getObjectProp(ScriptRuntime
  .java:1437)
   at
  org.mozilla.javascript.ScriptRuntime.getObjectProp(ScriptRuntime
  .java:1423)
   at
  org.mozilla.javascript.Interpreter.interpretLoop(Interpreter.jav
  a:3027)
   at
  org.mozilla.javascript.Interpreter.interpret(Interpreter.java:24
  87)
  

Local fix

Problem summary

• The JavaScript loop detection implementation instructs the
  JavaScript engine to invoke a callback that IBM BPM provides
  every 25 million JavaScript instructions. This callback checks
  whether the configured timeout was exceeded since the start of
  the JavaScript. If the timeout was exceeded, IBM BPM either
  throws a LoopDetectionException or logs an error message,
  depending on the configuration. If the script repeatedly calls
  Java methods that use most of the execution time, 25 million
  JavaScript instructions might take much longer than the
  configured timeout and the loop detection does not interrupt
  such long running scripts quickly.
  

Problem conclusion

• A fix is/will be available that allows you to configure  the
  number of JavaScript instructions between the calls to the
  callback for loop detection in the 100Custom.xml file:
  
    <common merge="mergeChildren">
   <javascript-engine>
    <instruction-threshold>250</instruction-threshold>
   </javascript-engine>
    </common>
  
  IBM BPM multiplies the configured value by 1000 before
  instructing the JavaScript engine to call the loop-detection
  callback. The default value is 250. This means that the
  JavaScript engine calls the IBM BPM loop detection callback
  every 250000 JavaScript instructions.
  
  On Fix Central (http://www.ibm.com/support/fixcentral), search
  for JR51504:
  
  1. Select IBM Business Process Manager with your edition from
    the product selector, the installed version to the fix pack
    level, and your platform, and then click Continue.
  
  2. Select APAR or SPR, enter JR51504, and click Continue.
  
  When you download fix packages, ensure that you also download
  the readme file for each fix. Review each readme file for
  additional installation instructions and information about the
  fix.
  

Temporary fix

• Not applicable
  

Comments

APAR Information

• 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

  BPM STANDARD

• Fixed component ID

  5725C9500

Applicable component levels

• R801 PSY

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