PM88077: S4C5/74597243 ABEND IN EZBTCUTL

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• An application listening on a TCP port is being shut down.  If a
  new connection (SYN packet) arrives for that port at the same
  time as the close for the listener socket is being performed,
  the potential exists for the TCB associated with the new
  connection to be freed twice.  The second attempt (probably
  associated with the SRB processing the inbound packet) will get
  an ABENDS04C5 RSN74597243.
  
  The resultant dump title will contain the phrase
     EZBTCUTL(ppppppp yy.ddd)+xxxxxx S4C5/74597243
  where the values will vary by maintenance level.  Examples seen
  for this have been:
  
     (UK75333 12.011)+0011E2
     (UK81852 12.263)+0011E2
  
  The stack should continue processing without other symptoms.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users of the IBM Communications Server                   *
  * for z/OS Version 2 Release 1 IP                              *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * Abend S4C5/74597243 in EZBTCUTL.                             *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply Fix                                                    *
  ****************************************************************
  There is a timing window in which a new connection started
  to a listener socket at the same time the socket is
  being closed may cause the TCB control block associated
  with the new connection to be freed twice.
  The second attempt to free the TCB will result in an abend.
  +-------------------------------------------------------------+
  + 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

• EZBTCPCN has been modified so that the TCB storage
  is only freed once.
  
  * Cross Reference between External and Internal Names
  

Temporary fix

Comments

APAR Information

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

  PM85519

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

Modules/Macros

• EZBTCPCN
  

Fix information

• Fixed component name

  TCP/IP V3 MVS

• Fixed component ID

  5655HAL00

Applicable component levels

• R210 PSY UK94777

     UP13/06/21 P F306

Fix is available

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