OA25322: ABEND0C4 IN MODULE ISTHSCEP +BA - TSOP IS RUNNING ON AN FMCB THAT IS FREED.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• ABEND0C4 in module ISTHSCEP + x'BA'.  The module is running
  on the TSOP of an FMCB that has been freed.
  UNBIND processing occurred on a session that was on an HPR
  pipe that had back-pressure due to a path-switch.  The pipe
  became PENDING_INACT as the UNBIND flowed out - causing the
  UNBIND to not reach the RPNCB.  When the pipe was being taken
  down, back-pressure relief re-scheduled the FMCB TSOP - just
  as it was being freed.
  Additional symptom: HSIDONTS
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of RTP connections.                *
  ****************************************************************
  * PROBLEM DESCRIPTION: ABEND0C4 in ISTHSCEP while running on   *
  *                      a PAB in a freed FMCB.                  *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The problem may be summarized as follows:
  1. A session is established over an RTP connection.
  2. The RTP connection goes into path switch, causing
     back pressure to be exerted on the session.
  3. An UNBIND is sent on the session.
  4. The UNBIND process proceeds to the point where SESSER
     is scheduled and the HS PAB is exitted for what should
     be the final time.
  5. The path switch fails and the RTP connection is terminating.
     As part of the termination process, back pressure relief
     processing schedules the HS PAB that just exitted.
  6. SESSER runs and frees the FMCB and HSICB.
  7. The HS PAB is dispatched and runs on the freed FMCB, abending
     when trying to set a bit in low core because the TSPHSICB
     pointer is 0.
  

Problem conclusion

• ISTTSCIS and ISTTSCOS are updated turn off the bit that
  indicates a session is being held for back pressure.  These
  modules will do this while processing session deactivation.
  
  ISTRPCRT, ISTRPCPU, and ISTNSCLR are included for maintenance
  purposes.
  

Temporary fix

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

Comments

APAR Information

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

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

  UA41567 UA41568 UA41569 UA41570

Modules/Macros

• ISTNSCLR ISTRPCPU ISTRPCRT ISTTSCIS ISTTSCOS
  

Fix information

• Fixed component name

  VTAM V4 MVS/ESA

• Fixed component ID

  569511701

Applicable component levels

• R1A0 PSY UA41567

     UP08/06/24 P F806

• R170 PSY UA41568

     UP08/06/24 P F806

• R180 PSY UA41569

     UP08/06/24 P F806

• R190 PSY UA41570

     UP08/06/24 P F806

Fix is available

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