PH14126: A03 ABEND DURING SHUTDOWN DUE TO A TIMING ISSUE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Customer is encountering a abendA03 during shutdown due to the
  timer task owning an S8 TCB. This was caused due to a socket
  being used by two tasks at the same time, that causes DFHSOTI
  to fail to switch off the S8 TCB at the right time. This leads
  to the A03 abend during shutdown.
  .
  Additional Keywords:
  abendA03 A03 DFHSOTI DFHTISR S8TCB S8 TCB
  KIXREVPAD
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS Users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: Hang at shutdown and an abendA03 due to *
  *                      the CICS timer task incorrectly         *
  *                      retaining ownership of an S8 TCB.       *
  ****************************************************************
  CICS has an SSL based TCPIPSERVICE with a non-zero SOCKETCLOSE
  value. When a web alias task completes it issues an async
  receive call to wait for the next request to arrive.  It then
  requests a timer notification for when the SOCKETCLOSE time
  expires.  If the task lost control between these two actions it
  is possible for the next request to arrive from the client
  before the timer notification is set.  This causes the timer
  notification to be set invalidly.
  
  The invalid notification will never get cancelled and will
  eventually expire.  When it expires and DFHSOTI processes the
  notification it must switch to an S8 TCB to close the socket.
  If another task is using the socket at the same time then it is
  possible for the timer task to fail to switch back to the QR TCB
  at the correct point and fail to disassociate the S8 TCB.
  
  The S8 TCB remains owned by the timer task.  When CICS is shut
  down the SO domain hangs waiting for the S8 TCB to be deleted.
  

Problem conclusion

• The CICS sockets domain has been changed to prevent the timer
  notification from being created invalidly.
  
  DFHSOTI has been updated to ensure the S8 TCB is always
  disassociated if that has not already happened.  A DFHSO0002
  message with code(x'0B0C') will be issued and a dump taken to
  diagnose why the S8 TCB was still being used.
  
  The CICS Transaction Server for z/OS V5.4 and V5.5 Knowledge
  Center has been altered as follows:
  
  (1)CICS Transaction Server for z/OS V5.4 :
  In'Home > CICS Transaction Server for z/OS 5.4.0 > Reference >
  Diagnostics > Trace Entries > Socket domain trace points'section
  the following new trace point is added :
  
  Point ID Module  Lvl  Type                 Data
  SO 0B0C  DFHSOTI EXC  EXITING_ON_AN_S8_TCB 1 TISR parameter list
                                              2 SO Anchor Block
  .
  (2)CICS Transaction Server for z/OS V5.5 :
  In'Home > CICS Transaction Server for z/OS 5.5.0 > Reference >
  Diagnostics > Trace Entries > Socket domain trace points'section
  the following new trace point is added :
  
  Point ID Module  Lvl  Type                 Data
  SO 0B0C  DFHSOTI EXC  EXITING_ON_AN_S8_TCB 1 TISR parameter list
                                              2 SO Anchor Block
  

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:

  UI66865 UI66866

Modules/Macros

• DFHSOS22 DFHSOS23 DFHSOTI  DFHSOTRI
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R100 PSY UI66865

     UP19/12/10 P F912

• R200 PSY UI66866

     UP19/12/10 P F912

Fix is available

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