PH09417: TASKS LOOP OR 0C4 AFTER CATA TASK INSTALLS A CONSOLE DEFINITION

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Unpredictable results including task hangs, loops, and program
  checks can occur during processing of a CATA task attached to
  autoinstall a console.
                                                                 .
  An unrelated task received an 0C4 in DFHPGHM, then went into a
  loop. The corresponding message is:
                                                                 .
  DFHPG0001 An abend (code 0C4/AKEA) has occurred at
    offset X'0714' in module DFHPGHM.
                                                                 .
  DFHPGHM is trying to get to the head of the PLCBs for the task,
  but the pointer in the PTA +x18 is zeroes (field PTA_PLCB_HEAD)
  so the 0C4 occurs. MVS system trace then shows the task looped
  between modules DFHPGHM and DFHKEDOM because the PREVIOUS
  pointer in the kernel stack for DFHPGHM points to itself.
                                                                 .
  The problem is that module DFHZATA2, who is processing the
  autoinstall of the console, issued an EXEC CICS command (like
  IGNORE CONDITION or HANDLE CONDITION) with R13 pointing to the
  CSA. But during processing of that EXEC CICS request, the CATA
  task lost control. And while CATA has lost control, another
  task also uses the register save area in the CSA. When CATA
  regains control, it begins processing with registers belonging
  to another task.
                                                                 .
  Previously DFHZATA2 had called DFHZATT but had not set up R13
  before/after the call. So when control returned to DFHZATA2
  from DFHZATT, R13 is pointing to the CSA, and that is the R13
  that will be used as its register save area for the next EXEC
  CICS call. The problem only happens if the timing is such that
  the CATA task loses control and another task also gets in to
  run and also saves its registers in the CSA.
                                                                 .
  Additional Symptom(s) Search Keyword(s): KIXREVxxx
  loop looping loops hang hangs hung 0C4 S0C4 abend0C4
  DFHDS0002 0068 DS0002 PG0001 DFHZATA  DFHZC6935 TCTTE
  

Local fix

• Define and install console terminals. To do this, you need to
  install terminal definitions that specify TYPETERM(DFHCONS)
  and appropriate CONSNAME().
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: Transaction CATA abend0C4 when          *
  *                      auto-installing an MVS CONSOLE.         *
  ****************************************************************
  An MVS MODIFY command has been entered at a CONSOLE to run a
  CICS transaction.
  Transaction CATA is started to auto-install the CONSOLE.
  The CONSOLE is successfully auto-installed, the transaction
  from the MVS MODIFY is successfully ATTACHED but register 13 is
  not restored to the EXEC environment after the attach.
  CATA loses control to other tasks.
  When CATA is resumed the next EXEC CICS command issued by
  DFHZATA2 will cause CATA to abend0C4.
  Another unrelated running task in the CICS region will also
  suffer unpredictable results.
  

Problem conclusion

• DFHZATA2 has been changed to ensure that register 13 is
  restored to the EXEC environment after calling DFHZATT.
  

Temporary fix

Comments

APAR Information

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

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

  UI62061 UI62062

Modules/Macros

• DFHZATA2
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R100 PSY UI62061

     UP19/03/23 P F903

• R200 PSY UI62062

     UP19/03/23 P F903

Fix is available

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