PI44402: WMQ: HIGH CPU DUE TO A LOOP IN CSECT CMQZRFPA OF LOAD MODULE CSQTOPLM

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• A loop occurs during MQGET browse processing in routine
  zrfConvertAllPropertiesToMQRFH2 in CSECT CMQZRFPA of load
  module CSQTOPLM.  The eyecatcher prior to the PSWs for EXT,
  CLKC, and DSP entries in systrace is
  | ..}...x4..zrfCon |
  | vertAllPropertie |
  | sToMQRFHEP(CSQTZ |
  | R10)T\-...T0\... |
  i.e. it has zrfConvertAllPropertiesToMQRFH and EP(CSQTZR10).
  
  The loop is occurring due to a ZRFP control block containing
  invalid data. The problem seems to have been caused by a
  destructive MQGET taking place at the same time as the
  browse, so the browse has been processing a reused IRH9 header
  block, so hence the ZRFP is incorrect.
  
  In the reported case, the application was a CICS transaction.
  It could not be killed, so the CICS region had to be cancelled.
  
  
  Additional Symptom(s) Search Keyword(s):
  performance looping inflight in-flight
  CSQTZR10
  

Local fix

• Cancel the looping application and restart it.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 *
  *                 Release 1 Modification 0.                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: Applications browsing a queue           *
  *                      containing messages with message        *
  *                      properties and/or RFH2 headers loop in  *
  *                      CMQZRFPA.                               *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  While browsing a queue, an application locates a message
  containing message properties (which may originally have been
  provided in an RFH2 header) and copies them from the pages
  containing the message to a temporary buffer, however just prior
  to the copy occurring the message was deleted by another
  application and the pages reused for a subsequent message, and
  so the reused data was copied into the temporary buffer. When
  CSQIMGE9 subsequently called CSQMHDRS to process any message
  properties, the invalid properties data can be passed to
  zrfConvertAllPropertiesToMQRFH or zrfMoveProperties. These
  routines expect valid properties data, however as the passed
  data was invalid, this resulted in a loop due to invalid values
  at the offset where a length was expected.
  

Problem conclusion

• CSQIMGE9 is changed to check if the message has been deleted
  prior to calling CSQMHDRS during browse operations.
  
  MQMSGPROP/K
  100Y
  CSQIMGE9
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

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

  PI49242 UI31933

Modules/Macros

• CSQIMGE9
  

Fix information

• Fixed component name

  WMQ Z/OS V7

• Fixed component ID

  5655R3600

Applicable component levels

• R100 PSY UI31933

     UP15/11/11 P F511 Ž

Fix is available

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