PH09238: ABN=0C4-00000004,U=MQSSTC ,C=MQ900.900.MMC -CSQMJCLU, M=CSQGFRCV,LOC=CSQMLPLM.CSQMJCLU CSQX519E 20/01/29 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• CHIN suffered the following abend but stayed up and no further
  issues were seen:
  
  ABN=0C4-00000004,U=MQSSTC  ,C=MQ900.900.MMC -CSQMJCLU,
  M=CSQGFRCV,LOC=CSQMLPLM.CSQMJCLU
  
  CSQMJCLU is at UI52881.
  
  The reason for this problem is that MQ is loading a channel
  object and making an internal copy of it.
  
  Unfortunately the code has picked up the wrong length of the
  control block because it is actually an older internal version
  of the block.
  
  Normally this extra data being copied is harmless and no
  negative effects are seen, however, in this particular case the
  object is located near the end of a Key 7 page and is
  immediately followed by a page of another Key.
  
  Because of this, instead of benignly copying some additional,
  unnecessary, data, instead it attempts to read from storage
  that cannot be accessed in the current mode and the S0C4-4
  protection exception abend occurs.
  
  ADDITIONAL SYMPTOM : CSQX519E ABEND0C4 ABENDS0C4
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of IBM MQ for z/OS Version 9       *
  *                 Release 0 Modification 0 and Release 1       *
  *                 Modification 0.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: When processing an MQICLU SPI request,  *
  *                      CSQMJCLU may get an 0C4 if there is a   *
  *                      pre V2.10 cluster channel being         *
  *                      inquired.                               *
  ****************************************************************
  When identifying objects, CSQMJCLU has logic specific to
  channels for allocating storage to copy the object into. PI91107
  added a new special case for channels but the way the code was
  added meant that the pre V2.10 channel logic no-longer worked as
  expected. With the incorrect amount of storage now being
  allocated for a pre V2.10 channel object an 0C4 may result when
  CSQMJCLU attempts to read beyond the end of an allocated storage
  block. The symptom will only be seen if the over-run goes into
  unallocated storage addresses.
  

Problem conclusion

• Code has been changed to allocate the appropriate amount of
  storage for pre V2.10 channels.
  

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:

  UI67620 UI67621

Modules/Macros

• CSQ7CBM  CSQ7CHND CSQ7VTBL CSQMICLU CSQMJCLU CSQXRCDX
  

Fix information

• Fixed component name

  IBM MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R000 PSY UI69037

     UP20/05/29 P F005 {

• R100 PSY UI69038

     UP20/05/29 P F005 {

Fix is available

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