PI43893: DFHAP0001 ABEND0C4 IN DFHZIS2 AND DFHCRIU WHEN DFHMIRS DEFINED AS CONCURRENCY=REQUIRED

APAR status

• Closed as documentation error.

Error description

• You are running CICS TS 5.2, and specify
  CONCURRENCY=REQUIRED for mirror program DFHMIRS.
  You receive the following errors:
  DFHAP0001 An abend (code 0C4/AKEA) has occurred at
            offset X'FFFFFFFF' in module DFHZIS2.
  DFHAP0001 An abend (code ---/ASRA) has occurred at
            offset X'11C2' in module DFHCRIU
  DFHRM0002 A severe error (code X'0377') has occurred
            in module DFHRMLSO.
  .
  The problem involves 2 CSMI mirror tasks.
  One task ends up picking up the other task's registers from
  the CSA, causing the above abends to occur.
  It involves modules DFHZIS2 and DFHAPPG overlapping using
  the register save area in the CSA, when the tasks  are
  running on different tcbs.
  Additional Symptom(s) Search Keyword(s): KIXREVEPH
  

Local fix

• make DFHMIRS CONCURRENCY=QUASIRENT
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS Users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: Message DFHAP0001 ('An abend (code      *
  *                      0C4/AKEA) has occurred at offset        *
  *                       X'FFFFFFFF' in module DFHZIS2') is     *
  *                      issued when DFHMIRS is defined          *
  *                      with CONCURRENCY=REQUIRED.              *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  An application does a DPL request to a remote region over an
  MRO connection resulting in a call to DFHMIRS in that region.
  DFHMIRS is defined with CONCURRENCY=REQUIRED and this results
  in a CHANGE_MODE call to swap to an open TCB before calling
  DFHMIRS.
  Running DFHMIRS on an open TCB is not supported for LU 6.2
  and MRO because it drives terminal control code which is not
  threadsafe.
  DFHMIRS itself will initiate a switch to an open TCB only
  if the request comes in over IPIC. This occurs regardless
  of the concurrency setting in the CSD definition for DFHMIRS.
  DFHMIRS must not be defined as CONCURRENCY(REQUIRED) but the
  explanation of how to change applications to run on an
  open TCB in the CICS Knowledge Centre does not make this clear.
  
  Additional Keywords 0C4 S0C4 AKEA abendAKEA AP0001 msgDFHAP0001
  

Problem conclusion

• The CICS Knowledge Center for CICS Transaction Server 4.2
  will be updated in the section "Scenarios > Running
  existing applications on open TCBs without code changes >
  Implementing the solution > Changing the PROGRAM resource
  definitions for the application" at the following address:
  "http://www-01.ibm.com/support/knowledgecenter/SSGMCP_4.2.0/com
  .ibm.cics.ts.scenarios.doc/threadperf/topics/impl_resdef_prog.h
  tml"
  Under the heading 'Before you begin' these sentences will be
  deleted:
  "DFHMIRS is not defined as CONCURRENCY(REQUIRED) because it
  might handle mirror transactions for programs that are not
  threadsafe. In that situation, the setting CONCURRENCY(REQUIRED)
  would cause an unnecessary switch to an open TCB."
  They will be replaced with the following:
  
  "DFHMIRS is not defined as CONCURRENCY(REQUIRED) because only
  function shipping over IPIC is threadsafe. For MRO and ISC
  the function shipping code is not threadsafe, so it is not
  possible to define DFHMIRS to run on an open TCB from the
  start. DFHMIRS itself will decide to switch to an open TCB if
  appropriate, that is only when invoked over IPIC links."
  
  In the same subsection the following sentence will be added
  to the end of the paragraph beginning 'For an application that
  uses a mirror transaction..':
  
  "DFHMIRS must not be defined as CONCURRENCY(REQUIRED)."
  
  The paragraph following this, beginning "Also note that a file
  control or temporary storage queue request.." will be altered to
  remove the 'Also note that' so that it reads as follows:
  
  "File control or temporary storage queue requests.."
  

Temporary fix

Comments

APAR Information

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

  PI37496

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

Fix information

Applicable component levels