PI15067: ABEND S4C5 /76680402 EZBTCFSP(UK96154 13.207)+000F50

Obtain the fix for this APAR.

APAR status

• Closed as unreproducible in next release.

Error description

• During the processing of an itevent wait macro, an abend4c5 is
  taken at offset x'F50' in EZBTCFSP when it determines, prior to
  deleting an event from the event queue, that the leftmost word
  of itevent_q_cdsrefs (itevent_q_numrefs) is zero.
  Alternate symptom:  ABEND S4C5/76650402 EZBTCFRD(UK96486
  13.219)+00BDDC
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users of the IBM Communications Server for z/OS Version  *
  * 2 Release 1: Using Asynchronous connections                  *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * An async connect request causes unpredictable results        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply PTF                                                    *
  ****************************************************************
  

Problem conclusion

• An async connect request is issued and goes into a WAIT in
  routine EZBTCFCW in module EZBTCFCN. While in the WAIT, control
  is returned to the application and it issues a close(). This
  causes the TCB ref count to go to zero which causes both the TCB
  storage and itevent storage to be freed and reused. When the
  WAIT is posted, the itevent code decrements the ref count in the
  itevent control block (itevent_q_numrefs) which is being used by
  another connection now. This causes the ref count to go to -1.
  This can cause unpredictable results.
  

Temporary fix

Comments

• A TCB_REF begin_ref will be added for the async1 case before the
  WAIT is issued in EZBTCFCW and an end_ref will be issued after
  the WAIT. This will ensure that the decrement of the itevent ref
  count will not be done against an instance of the itevent
  control block for a different connection.
  

APAR Information

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

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

  UI17308

Modules/Macros

• EZBTCFCN
  

Fix information

• Fixed component name

  TCP/IP V3 MVS

• Fixed component ID

  5655HAL00

Applicable component levels

• R210 PSY UI17308

     UP14/06/06 P F406

Fix is available

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