PH20502: ABEND0C4 DFHISIS +X'0FC4'

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• An abend0c4 occurred on instruction at + x'0FC4' in module
  DFHISIS. The abend occurred trying to reference an ISSB block
  on the free chain and the buffer pointer within is zeroes.
  Attempting to address the low core caused the abend0c4.
   It looks like there was a timing error and the following
  sequence of events occurred:
  - Transaction number 44419 was allocating ISSB termid /AE3 and
    got suspended when switching to the QR TCB.
  - A CONNECTION error occurred while 44419 was suspended.
    This drove CISE task to run to handle the error and TERMINATE
    the IPCONN (Attach CIST).
    ISSB /AE3 was freed by CISE because the ISSB_TRAN_NUMBER had
    not yet been initialised.
    The IS_BUFF was FREEMAINed accordingly.
  - The ISSB was allocated for use and freed by a later CIST (task
    44450) during the IPCONN release process.
  - When FD50 (task 44419) was resumed it continued the ISSB
    allocation and ISSB /AE3 was obtained.
    An attempt to move data into the IS_BUFF, which now had an
    address of x'00000000', caused the abend0C4.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All                                          *
  ****************************************************************
  * PROBLEM DESCRIPTION: Message DFHIS0001 and abend (code       *
  *                      S0C4/AKEA) offset X'0FC8' in module     *
  *                      DFHISIS.                                *
  ****************************************************************
  A path exists within IPIC code where an attempt is made to
  update an ISSB control block after it has been freemained.
  
  In the reported problem, CICS_A and CICS_B were connected using
  IPIC.  A task running on CICS_A shipped a request to CICS_B but
  got suspended whilst doing a switch to the QR TCB.  At the time
  of the suspend, the transaction number had not been populated
  into ISSB_TRAN_NUMBER - a field within the ISSB (which
  represents an IPCONN session).  Whilst suspended, a connection
  error occurred.  This caused CISE, the IPCONN error transaction
  to run which terminated the IPCONN and because ISSB_TRAN_NUMBER
  was not initialised, FREEMAIN the associated ISSB.  When the
  task resumed it attempted to reference the freemained ISSB and
  0C4'd.
  
  Keywords: IS0001 msgDFHIS0001 140F 140B abend0C4 abendS0C4
  

Problem conclusion

• DFHISAL has been modified so that ISSB_TRAN_NUMBER is
  initialised in the ISSB control block before any potential
  SUSPEND. This ensures an orderly termination of the task.
  

Temporary fix

Comments

• ×**** PE20/03/18 FIX IN ERROR. SEE APAR PH23446  FOR DESCRIPTION
  

APAR Information

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

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

  UI68406 UI68407 UI68408

Modules/Macros

• DFHISAL
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R000 PSY UI68408

     UP20/03/17 P F003

• R100 PSY UI68407

     UP20/03/17 P F003

• R200 PSY UI68406

     UP20/03/17 P F003

Fix is available

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