PI68960: 0C4 00000011,M=CSQXDISP,LOC=CSQXRCTL.CMQXRSTF

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• 0C4-00000011,M=CSQXDISP,LOC=CSQXRCTL.CMQXRSTF
  The client has sent a heartbeat, and a communication error has
  occurred when the CHIN has tried to send a heartbeat response
  (TCP/IP EPIPE error). This has resulted in cleanup  processing
  being performed by the receive-thread, which resulted in the
  rstStreamQueue control block being released. However,
  processing by the associated async-consume thread tried to
  access the rstStreamQueue control block, which resulted in the
  0C4.
  
  .
  Additional keywords:
  ABEND0C4 ABENDS0C4 S0C4 S00C4 0C4
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users of IBM MQ for z/OS Version 9 Release 0             *
  * Modification 0.                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * A SVRCONN channel configured with SHARECNV > 1 generates 0C4 *
  * abend in CMQXRSTF or CSQXCCMX.                               *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * none                                                         *
  ****************************************************************
  While processing a heartbeat request from the client, the
  receive thread for the channel attempted to send a heartbeat
  segment, and this failed due to the client no longer being
  available. The receive thread began terminating all
  conversations on the channel, however an error in the
  serialisation between the receive thread and the async task for
  the channel allowed the rstStreamQueue structure for one of the
  conversations to be freed by the receive thread while it was
  still being used to process a message that had been consumed by
  the async thread. When the async thread attempted to reference
  this freed control block, the dispatcher on which the receive
  and async threads were running abended S0C4.
  

Problem conclusion

• cciReceiveThreadFn is changed to inform the async thread to stop
  consuming messages prior to ending the conversations on a
  failing channel.
  

Temporary fix

Comments

APAR Information

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

  PI62084

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

  UI41641

Modules/Macros

• CSQXCCAX
  

Fix information

• Fixed component name

  MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R000 PSY UI41641

     UP17/02/01 P F701

Fix is available

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