PK15562: ABEND0C4 DBFICLI0 FNCBREPS ZER0.

APAR status

• Closed as program error.

Error description

• Customer suffered abend0C4 in DBFICLI0+x'2D4' PQ96005 level.
  IMS has received a NOTIFY response NCB with FNCBREPS zero.
  This should be the address of the EPST waiting for the response.
  It's not clear where this notify came from at this point,
  but the logic in DBFICLI0 which attempts to locate the PST
  address for this EPST is faulty. The logic first checks the
  list of FastPath server ITASK EPSTs in the ESCD, and if no
  match there, scans first the APSTs and then the DPSTs looking
  for a match on PSTEPST vs FNCBREPS. Unfortunately, APSTs at
  least in IMS V9, don't seem to have EPSTs associated with them.
  PSTEPST is zero which matches FNCBREPS. This causes DBFICLI0
  to attempt to use the zero FNCBREPS as an EPST pointer and
  the CS of EPSTNSEQ causes an 0C4 attempting to update low core.
  DBFICLI0 needs to make an explict check for FNCBREPS zero and
  treat this as a not-found condition, which will cause the FNCB
  to be queued to DBFCSTS2 for timeout cleanup. DBFCSTS2 also
  needs to handle zero FNCBREPS as an error case when checking
  FNCBs on ESCDRSPQ vs this FNCB (in case there is FNCB on
  ESCDRSPQ with zero FCNBREPS). If no match is found then
  we will proceed to discard the FNCB safely.
  The original problem, of where this phantom notify came from,
  has not been diagnosed at this point.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: IMSFP R810 DEDB USERS                        *
  ****************************************************************
  * PROBLEM DESCRIPTION: The notify control block may have       *
  *                      a zero address in the FNCBREPS field    *
  *                      for the responder's EPST. This causes   *
  *                      ABEND0C4 when posted.                   *
  ****************************************************************
  * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
  ****************************************************************
  The notify control block field FNCBREPS has an invalid
  address ( zero ) for the EPST that is responding in the
  notify process of the datashare environment. The invalid
  address causes an ABEND0C4 to occur when it gets posted.
  An error path will be added to DBFICLI0 to discard the FNCB
  when FNCBREPS is zero.
  

Problem conclusion

•  AIDS: RIDS/FP RIDS/DEDB FP DEDB
    DEP: RIDS/FP D/FP
    GEN:
  SYSPLEXDS
  
  *** END IMS KEYWORDS ***
  THE FOLLOWING MODULE WAS MODIFIED TO CORRECT THE PROBLEM:
  **************************************************************
  * DBFICLI0
  **************************************************************
  
  DBFICLI0 - code added to prevent an FNCB with invalid FNCBREPS
             to continue.
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

  PK14916

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

  UK10079

Modules/Macros

•    DBFICLI0
  

Fix information

• Fixed component name

  IMS V8

• Fixed component ID

  5655C5600

Applicable component levels

• R800 PSY UK10079

     UP05/12/16 P F512