PM67374: DFHFC0150 AN ATTEMPT TO RELEASE LOCKS FOR UNIT OF WORK X'UOWID' FAILED.VSAM RLS RETURN CODE X'00000008' RE 12/07/25 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• CICS TS 4.1 and VSAM RLS
  CICS attempts to release VSAM RLS locks. Unfortunately CICS gets
  back VSAM RC8 RSN185 (x'B9'). CICS then issues message DFHFC0150
  saying that it failed to relase the locks.
   The rc8 with rsn185 means:
   | 185(X'B9')   For MACRF=RLS, the user task was cancelled while
   |              the request was being processed.
  "We think the problem may be in the way CICS is reusing the RPL
  for the control ACB when performing the IDALKREL to release
  locks as part of synchpoint processing. This seems to running
  in threadsafe mode, and we have a new IDALKREL that seems to be
  issued USING THE SAME RPL, before fully processing the first
  request.  It appears that the chain of RPLs used for these
  IDALKREL requests may have an RPL pointing back to itself,
  causing improper reuse of the same RPL.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users with UK66252 applied.         *
  ****************************************************************
  * PROBLEM DESCRIPTION: During a CICS SYNCPOINT, an attempt to  *
  *                      release locks for an RLS file failed.   *
  *                      VSAM responded with return code 08,     *
  *                      reason code x'B9'.                      *
  *                      CICS issues message DFHFC0150.          *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  CICS is running with FCQRONLY=YES. Since the introduction of
  threadsafe syncpoint, CICS syncpoints can be invoked under an
  open TCB. If this happens, it is possible that file control
  DFHFCRC PERFORM_COMMIT processing could also be called under
  the open TCB.
  The logic in DFHFCCA RELEASE_LOCKS sees that FCQRONLY is in
  effect, and so does not obtain the global RPL lock before
  manipulating the active RPL chain. This is done as a
  performance enhancement, since locking is not necessary when all
  work is done on the QR TCB. Without locking in place, and when
  running on an Open TCB, updates to the chains can interleave,
  and so cause corruption of the free RPL chain.
  This can lead to an element in the free RPL chain pointing back
  to itself. Once in this state, it is possible that two tasks can
  be allocated the same RPL. This could then allow two separate
  calls to VSAM to interfere with one another, causing one VSAM
  request to be terminated early with the x'B9' reason code.
  CICS issues msgDFHFC0150.
  Additional Keywords: IDALKREL FC0150 msgFC0150
  

Problem conclusion

• UK66252 UK67848  UK75374  UK75381
  DFHAPSI has been updated to ensure that DFHFCRC is called on an
  appropriate TCB during syncpoint. If FCQRONLY is in effect, this
  will be the QR TCB.
  

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

APAR Information

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

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

  PM69833 UK81217

Modules/Macros

•    DFHAPSI  DFHFCRC
  

Fix information

• Fixed component name

  CICS TS Z/OS V4

• Fixed component ID

  5655S9700

Applicable component levels

• R600 PSY UK81217

     UP12/08/24 P F208

Fix is available

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