PH67647: MQ Z/OS: IMPROVE THE CHECKING FOR MISMATCHED EARLY CODE.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• IBM MQ Early Code:
  https://www.ibm.com/docs/en/ibm-mq/9.4.x?topic=mq-update-zos-lin
  says that some IBM MQ load modules need to be added to MVS for
  IBM MQ to act as a subsystem. This code is known as Early code.
  
  The early code comprises the following load modules: - CSQ3INI
  and CSQ3EPX in the library thlqual.SCSQLINK - CSQ3ECMX in the
  library thlqual.SCSQSNLx, where x is the language letter for
  your national language:
  
  That link has instructions for updating the code in the LPA,
  which you do during migration and possibly also after applying
  PTFs. This document and the PTF HOLDDATA both say that CSQ3INI
  and CSQ3EPX need to be updated with a SETPROG command.
  
  If there is a mismatch between the levels of CSQ3INI and
  CSQ3EPX, there can be various results, so this APAR is to
  improve the checking done to detect a mismatch.
  
  For example, when CSQ3EPX was updated to the UI99891 level but
  CSQ3INI was not, there were bad results due to a difference in
  the size of the internal ERLY control block. Symptoms included:
  - ABEND0C4 in CSECT CSQ3RS0X in load module CSQ3EPX: IEA794I SVC
  DUMP HAS CAPTURED: DUMPID=nnn REQUESTED BY JOB (ssidMSTR) DUMP
  TITLE=ssid,ABN=0C4-00000004,U= ,C=MQ900.940.SSSC-CS
  Q3RS0X,M=CSQ3RS0X,PSW=077C20009C70E13A,ASID=nnnn CSQV086E QUEUE
  MANAGER ABNORMAL TERMINATION REASON=00E80100
  
  - 8-byte storage overlays in z/OS Key 7 (KEY7) storage after an
  ERLY control block as its size changed from x'90' to x'98'. If
  the storage after it is in a different key, the 0C4 occurs. If
  the storage after it is in Key 7, the overlay occurs.
  
  The storage for the ERLY block is obtained by CSECT CSQ3UR00 in
  load module CSQ3INI, so when that module was back-level, it did
  not obtain enough storage.
  
  - In a reported case, the overlayed storage was an z/OS SSVT
  block, and the nature of the overlay resulted in an auto-ipl of
  the LPAR.
  

Local fix

• Make sure that both CSQ3INI and CSQ3EPX are updated to the same
  level by following instructions in the IBM Documentation or in
  PTF HOLDDATA.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of IBM MQ for z/OS Version 9       *
  *                 Modification 4 Release 0                     *
  ****************************************************************
  * PROBLEM DESCRIPTION: When updating the Early Code,           *
  *                      mismatched version levels between load  *
  *                      modules CSQ3INI and CSQ3EPX may occur,  *
  *                      for example if only one updated load    *
  *                      module is loaded into the LPA whilst    *
  *                      the other is not. This can lead to      *
  *                      queue managers failing to start after   *
  *                      seeing messages such as CSQV086E in the *
  *                      log.                                    *
  ****************************************************************
  There are currently no checks in the Early Code to detect
  mismatches between version levels of load modules. These
  mismatches can cause inconsistencies between components, such as
  differences in control block definitions. These inconsistencies
  may lead to problems like storage overlays when loading and
  writing to these structures, resulting in queue managers failing
  to start.
  

Problem conclusion

• Several checks have been put in place to detect mismatches in
  version level between modules CSQ3INI and CSQ3EPX when updating
  the Early Code. If a mismatch is detected, the system will abend
  with code 5C6-00F30112.
  

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:

  UO06816

Modules/Macros

• CSQ3EC0X CSQ3UR00 CSQARIB
  

Fix information

• Fixed component name

  IBM MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R400 PSY UO06816

     UP26/04/14 P F604 ¢

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.