PK71308: TIGHT LOOP ON L8 TCBS BECAUSE CHAIN ELEMENT CCNVG_CCE POINTS BACK TO ITSELF.

Obtain the fix for this APAR.

APAR status

• Closed as unreproducible.

Error description

• Tight loop on L8 TCBs (module DFHCCNVG) may apear because the
  next pointer of the chain element CCNVG_CCE does point to
  itself.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: MSGDFHAP0001 An abend (code ---/AKEC)   *
  *                      has occurred at offset X'136E' in       *
  *                      module DFHCCNVG.                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  A loop occurs in DFHCCNVG routine create_conversion_token. This
  happens because the conversion element addressed by
  ccnva_conv_chain points to itself instead of the next
  conversion element.
  Earlier on there have been 2 requests to create conversion
  tokens which executed in parallel on two L8 TCBs.
  DFHCCNVG uses inline getmains to acquire conversion elements
  from the quickcell subpool CCNV_CCE.
  These getmains are not single threaded and the two callers
  of DFHCCNVG ended up acquiring the same quickcell element.
  The first task to complete placed the quickcell element on
  the ccnva_conv_chain.
  The second task placed exactly the same element on this chain
  which resulted in the first element pointing to itself.
  All subsequent attempts to create new conversion elements for
  codepages which don't match the existing conversion element
  will suffer a loop which leads to message DFHAP0001 and a
  CV0001 system dump.
  
  ADDITIONAL KEYWORDS :- AP0001
  

Problem conclusion

Temporary fix

•             *********
              * HIPER *
              *********
  FIX AVAILABLE BY PTF ONLY
  

Comments

• DFHCCNVG has been changed to use a full domain call when
  getmaining and freemaining conversion elements from subpool
  CCNV_CCE. This ensures single threading under the control of the
  SMLOCK.
  

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UK39649

Modules/Macros

•    DESCCNVG DFHCCNVG
  

Fix information

• Fixed component name

  CICSTS V3 Z/OS

• Fixed component ID

  5655M1500

Applicable component levels

• R400 PSY UK39649

     UP08/09/12 P F809

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.