PH58725: MQ Z/OS : CSQX053E XFFSRSTMVSASYNCCONSUMERTHREAD FOLLOWED INITIAL S0C4 ABEND

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• In CHIN job log you can observe the below snap dump follows the
  0C4 abend:
  At 01.56.56 0c4-4 abend occurred due to channel exit error:
  01.56.56 STC11495  +CSQX111E +CSQ1 CSQXDISP User channel exit
  error, TCB=00ABDE88  238
     238              reason=0C4000-00000004
  
  At 01.56.57 the channel ended abnormally and it's followed by
  CSQX053E
  01.56.57 STC11495  +CSQX599E +CSQ1 CSQXRESP Channel CHIN1 ended
  abnormally
  01.56.57 STC11495  +CSQX053E +CSQ1 CSQXFFST Error information
  recorded in CSQSNAP data set
  the snap dump PSW points at:
   *X...XFFSrstMVSAsyncConsumerThrea*
   *d.......MOVR.........5.qX...XINS*
   *................................*
  
   *        ....rstMVSAsyncConsumerT*
  *hread: lpiSPIMQGETM Failed.....S*
  
  Each of the FFSTs are a result of an internal MQGET by a
  channel async consumer thread failing with MQRC_HCONN_ERROR.
  These are a consequence of the initial S0C4 abend in CSQ4BAX3.
  Recovery for a channel abend disconnects each conversation from
  the QMGR. This will result in any gets from the async consumer
  thread for that shared conversation failing with
  MQRC_HCONN_ERROR.
  The problem then is that recovery processing in rriCleanProcess
  doesn't correctly handle cleanup from abends for SHARECNV > 0.
  SHARECNV > 0 channels have separate receive and async threads
  but the cleanup doesn't account for this.
  
  It can potentially result in CHINIT failing to terminate
  normally.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of IBM MQ for z/OS Version 9       *
  *                 Release 3 Modification 0, and                *
  *                 Release 4 Modification 0.                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: An abend in a security exit may result  *
  *                      in message CSQX111E in the channel      *
  *                      initiator. An FFST from                 *
  *                      rstMVSAsyncConsumerThread may occur and *
  *                      cause the channel initiator to hang     *
  *                      when stopping                           *
  ****************************************************************
  rriCleanProcess is called after a user exit abends to shutdown
  the affected channel, however, thie function did not terminate
  asynchronous consumer threads which would result in FFSTs from
  rstMVSAsyncConsumerThread and the channel initiator being unable
  to shutdown due to the left over thread.
  

Problem conclusion

• rriCleanProcess has been corrected to terminate async consumer
  threads. As a result, FFSTs are no longer issued from
  rstMVSAsyncConsumerThread and the Channel Initiator no longer
  hangs on shutdown.
  

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:

  UI98786 UI98787

Modules/Macros

• CSQXRCAP
  

Fix information

• Fixed component name

  IBM MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R300 PSY UI98787

     UP24/11/16 P F411

• R400 PSY UI98786

     UP24/11/16 P F411

Fix is available

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