PH15770: DFHDU0004 OR DFHKE0303 OR UNPREDICTABLE RESULTS DUE TO OVERLAY OF DFHDUANCHOR DUMP DOMAIN ANCHOR

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• New code at Transaction Server R5.5 (CICS R720) in module
  DFHDUIO may cause an overlay of the Dump Domain Anchor Block.
  The comment at the beginning of the section of code says:
    " Process if autoswitching of datasets
      is not currently being performed."
  The code includes
    ?storage  (RELEASE)
    length  (open_block.len)
    addr    (dua.openblok_ptr)
  Instead of releasing the intended storage, it releases
  storage in the middle of the DUA (Dump domain anchor block)
  at offset +x'C0' for x'A8' bytes.  This allows MVS to assign
  the storage to some other process, which could then overlay
  the Dump domain anchor block. This may cause unpredictable
  results.
  
  Two symptoms have been found at the time the APAR opened.
  .
  CASE # 1
  If SysView module GSVCGSVS is installed, the overlay may include
  
  -  zeros   x'00000000'
  -  blanks  x'40404040'
  -  "NONE"  x'D5D6D5C5' at offset +x'120'
  This causes an infinite loop in DFHDUTM code and message:
  DFHDU0004 A POSSIBLE LOOP HAS BEEN DETECTED
   AT OFFSET FFFF IN MODULE DFHDUTM
      In IPCS, the Kernel Error Table it shows:
    Error Code:  ---/AKEC    Error Type:  RUNAWAY
  Abend AbendAKEC AKEC  AbendAICA AICA
    CICS Registers and PSW.
  PSW:  478D1000 80000000 00000000 2217DE90 DFHDUTM  +x'1F98'
     when DFHDUTM is at base level code, HCI7200.
  Instruction Length:   2
  Interrupt Code:  78
    CICS internal trace shows that the last request made by
  transaction COIE was
  EIP  ENTRY INQUIRE-EXITPROGRAM
  UEIQ ENTRY INQUIRE_NEXT BROWSE_TOKEN...
  UEIQ EXIT  INQUIRE_NEXT/EXCEPTION REASON(END_OF_EXIT_PROGRAMS)
    The CSA time stamp matches this last trace entry because the
  QR TCB isn't redispatched until the loop ends at abend time.
  DU 0602 DUTM *EXC* RECOVERY-ENTERED
         FUNCTION(GETNEXT_SYSTEM_DUMPCODE)
  .
  CASE # 2
  Multiple AbendS0C6 S0C6 0C6 during shutdown
  During processing of a message, DFHDUDT is called for dump
  processing and begins taking 0C6 abends due to character
  data x'4F's or "\" that have overlaid the DUA (Dump anchor
  block). Eventually, a recursive abend is detected:
  
  DFHDU0001 AN ABEND (CODE 0C6/AKEA) HAS OCCURRED AT OFFSET
    X'0BE6' IN MODULE DFHDUDT.
  DFHKE0303 A RECURSIVE ABEND HAS BEEN DETECTED BY THE KERNEL
    DOMAIN.
  .
  Additional Symptom(s) Search Keyword(s): KIXREVPAD
  0C4 abend0C4 S0C4 DFHDUANC dump domain anchor DUANC
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: Overlay of part of the CICS DU domain   *
  *                      anchor.                                 *
  ****************************************************************
  When a CICS dump data set, DFHDMPA or DFHDMPB, is closed,
  part of the DU domain anchor (DUA) storage is released.
  If some other component or product obtains and uses the
  released storage, then the DU domain can fail or behave
  incorrectly.
  Additional keywords: Open_Block OpenBlok_Ptr FREEMAIN
  

Problem conclusion

• DFHDUIO has been changed to release the correct piece of
  storage.
  

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:

  UI65118

Modules/Macros

• DFHDUIO
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R200 PSY UI65118

     UP19/09/04 P F909 ¢

Fix is available

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