JR48395: INTRODUCTION OF THE CAPABILITY TO DETECT INFINITE LOOPS IN CUSTOMER WRITTEN JAVASCRIPT ACTIVITIES

Version 8.5 Refresh Pack 5 for the IBM Business Process Manager products
Download Version 8.0.1 Fix Pack 3 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

• It is possible for JavaScript activities in IBM BPM applications
  to be coded so that infinite loops can occur. Identifying which
  JavaScript is looping might be difficult. However, resources are
  affected when JavaScripts loop. For example, Process Center or
  Process Server threads are lost until the server is terminated.
  Lost threads can affect server availability.
  
  A fix is available that helps identify JavaScripts that are in
  infinite loops and, optionally, terminate them.
  

Local fix

• N/A
  

Problem summary

• It is possible for JavaScript activities in IBM BPM applications
  to be coded so that infinite loops can occur. Identifying which
  JavaScript is looping might be difficult. However, resources are
  affected when JavaScripts loop. For example, Process Center or
  Process Server threads are lost until the server is terminated.
  Lost threads can affect server availability.
  In some cases, it might be possible to terminate the process
  instance, but it is not always possible.
  This enhancement improves the stability and availability of
  Process Center and Process Server by detecting and terminating
  infinite loops within a JavaScript activity.
  

Problem conclusion

• IBM BPM monitors the number of executed JavaScript instructions
  in each Script Activity.  The JavaScript run-time notifies the
  BPM engine when the instruction counter reaches a limit that is
  set by the BPM engine.
  After the number of executed JavaScript instructions have
  reached the limit, the BPM engine checks how long the Script
  Activity has been executing.
  Notes:
  - Calls to Java methods or IBM BPM JavaScript API calls, e.g.,
    tw.system.executeServiceByName count as 1 instruction.
  - JavaScript code within managed server-side files referenced
    by server side components counting as individual instructions
    and not just one
  - Currently a hard coded limit of 25 Million JavaScript
    instructions are used
  - APAR JR51504 introduces the capability to change this limit.
    Please refer to this APAR for further details.
  If the "loop-detection-exception" value is set to "false", one
  of the following messages will be written to SystemOut.log:
  "CWLLG2261W: Infinite loop suspected after {0} seconds in
  ''UKNOWN'' activity. If this script is not in a loop, increase
  the loop-detection-duration property."
  "CWLLG2263W: Infinite loop suspected after {0} seconds in
  ''{1}'', for BPD ''{2}'', script activity ''{3}''. If this
  script is not in a loop, increase the loop-detection-duration
  property.
  "CWLLG2265W: Infinite loop suspected after {0} seconds in
  service ''{1}''. If this service is not in a loop, increase the
  loop-detection-duration property."
  If the "loop-detection-exception" value is set to "true", one of
  the following messages will be written to SystemOut.log:
  "CWLLG2262E: Infinite loop detected after {0} seconds,
  ''UKNOWN'' activity terminated. If this script is not in a loop,
  increase the loop-detection-duration property.");
  "CWLLG2264E: Infinite loop detected after {0} seconds in
  ''{1}'', for BPD ''{2}'', script activity ''{3}'' terminated. If
  this script is not in a loop, increase the
  loop-detection-duration property.
  "CWLLG2266E: Infinite loop detected after {0} seconds, service
  ''{1}'' terminated. If this service is not in a loop, increase
  the loop-detection-duration property."
  If the loop-detection-duration is exceeded, it is assumed that
  the activity is in an endless loop.  The default duration is set
  to 20 seconds, but it is configurable (see below).
  By default, when an endless loop is detected, the BPM engine
  writes a Warning to SystemOut, but the Script Activity
  continues.  To configure the BPM engine to terminate infinitely
  looping script activities, set the loop-detection-exception
  property to the value true.
  You can configure the JavaScript loop detection parameters in
  100Custom as follows:
  <common merge="mergeChildren">
    <javascript-engine>
      <loop-detection-duration
  merge="replace">90</loop-detection-duration>
      <loop-detection-exception
  merge="replace">true</loop-detection-exception>
    </javascript-engine>
  </common>
  FIX AVAILABILITY:
  iFix for 8.0.1.1 is available on Fix Central, search for APAR
  JR48395 at http://www.ibm.com/support/fixcentral/
  iFix for 8.0.1.2 is available on Fix Central, search for APAR
  JR48395 at http://www.ibm.com/support/fixcentral/
  iFix for 8.5.0.1 is available on Fix Central, search for APAR
  JR48395 at http://www.ibm.com/support/fixcentral/
  Fix is also targetted for inclusion in next fixpack for BPM
  8.0.1, BPM 8.5.0
  When obtaining any of the above fixes, be sure to download the
  accompanying readme, for itself, and any prerequisite fixes, and
  review them thoroughly.
  

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

     UP

• R850 PSY

     UP