PM43452: EZBTCITS(HIP61C0 10.097)+000198 S0C4/00000011 DURING TCPIP SHUTDOWN

APAR status

• Closed as fixed if next.

Error description

• TCPIP is stopping.  Any outstanding events on TCP connections
  are being posted.  If an application thread is canceled while
  waiting in a TCPIP event, the event is not cleared from the
  connection, but the DUCB can be reused.  When TCPIP attempts to
  post the event, the DUCB storage will be referenced.  If the
  storage has been freed, an abend0C4 will occur in EZBTCITS.
  .
  VERIFICATION STEPS:
  1) TCPIPCS STATE shows TCPIP is stopping state
  2) The dump shows EZBTCITS using a DUCB from the itevent token
  but the page of storage for the DUCB is not allocated.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of the IBM Communications Server   *
  *                 for z/OS Version 1 Release(s) 10, 11, 12     *
  *                 and 13 IP:                                   *
  ****************************************************************
  * PROBLEM DESCRIPTION: Abend0c4 in module EZBTCITS following   *
  *                      stop of TCPIP stack.                    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  An application program is canceled while one of its threads
  is waiting on a TCPIP event, in this case a read event.
  TCPIP cleanup processing for a cancel does not clear the
  outstanding event.  The read event on the associated TCB
  (connection) still points to the DUCB which originally
  waited on this event.  DUCB contraction eventually occurs,
  and the DUCB is freed.  Later, TCPIP is shutdown via a stop
  command.  Shutdown processing attempts to post the event,
  and an abend0c4 in module EZBTCITS occurs when the residual
  DUCB storage is referenced.
  
  Cancel processing should be amended to remove the outstanding
  event.
  +-------------------------------------------------------------+
  + Please check our Communications Server for OS/390 homepages +
  + for common networking tips and fixes.  The URL for these    +
  + homepages can be found in Informational APAR II11334.       +
  +-------------------------------------------------------------+
  

Problem conclusion

Temporary fix

Comments

• This APAR is being closed FIN (Fixed If Next) with concurrence
  from the submitting customer. This means that a fix to this
  APAR is expected to be delivered from IBM in a release (if any)
  to be available within the next 36 months.
  
  This problem will be tracked as Feature F153955.
  
  The solution for this APAR is included in
  CS for zOS Version 2 Release 1.
  

APAR Information

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

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

Fix information

Applicable component levels

• R1A0 PSN

     UP

• R1B0 PSN

     UP

• R1C0 PSN

     UP

• R1D0 PSN

     UP