PM16608: DFHDS0002 A SEVERE ERROR (CODE X'0075') HAS OCCURRED IN MODULE DFHDSSR CSOL IMMCLOSE

Obtain the fix for this APAR.

APAR status

• Closed as unreproducible.

Error description

• CICS produces the following message,
  
  DFHDS0002  A severe error (code X'0075') has occurred in
             module DFHDSSR.
  
  The running task is CSOL on the SO TCB, and the stacks are as
  follows:
  
  INITIAL_LINK
  DFHAPLI1
  CICS_INTERFACE
  DFHSOLS
  LISTEN_SOLS
  IMMCLOSE
  DFHSOS03
  DFHDSSR
  SEND_MSG
  DFHMEME
  SEND
  CONTINUE_SEND
  TAKE_A_DUMP_FOR_CALLER
  The web-alias task on the SO KTCB is suffering a problem during
  socket close processing because the socket  it is trying to
  close has already been closed.
  It is likely this task has been performing a socket SEND for
  this socket when CSOL is trying to close the socket.
  It appears that the suspend token gets mixed up and Dispatcher
  ends up in wrong state. DFHDS0002 code 0075 will occur when CSOL
  deletes the suspend token.
  
  Additional Symptom(s) Search Keyword(s): KIXREVJXD
  ---------------------------------------
  There are numerous exception trace entries when CSOL
  is running on the SL TCB,
  
  ASYNCIO_ERROR RETURN_VALUE(-1) RETURN_CODE(113)
  REASON_CODE(1179011C)
  
  See the following trace exception when CSOL is running on the
  SO TCB,
  
    DEL_SUSP_SUSP_TOK_IN_USE - FUNCTION(DELETE_SUSPEND)
    SUSPEND_TOKEN(004F4739)
  
  Also, see the following trace exception entries when web-alias
  task is running on the SO TCB,
  
  IOCTL_ERROR RETURN_VALUE(-1) RETURN_CODE(113)
              REASON_CODE(05BC011C)
  CLOSE_ERROR RETURN_VALUE(-1) RETURN_CODE(113)
              REASON_CODE(0523011C)
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All                                          *
  ****************************************************************
  * PROBLEM DESCRIPTION: MSGDFHDS0002 severe error code 0075 has *
  *                      occurred in DFHDSSR when called from    *
  *                      DFHSOS03.                               *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  A web-alias task is performing a socket send. While the send is
  in progress, an IMMCLOSE of the TCPIPSERVICE which owns the
  sending socket occurs.
  DFHSOS03 is called by the CSOL task to perform a close of the
  sending socket. DFHSOS03 contains logic to detect socket I/O
  by another task on the socket which is scheduled for closure.
  DFHSOS03 will suspend to allow any in progress socket I/O to
  complete before the socket cleanup gets driven.
  A suspend token and waiting flag exist within the socket object
  to allow the closing task ( CSOL in this case ) and the I/O
  bound task ( web alias ) to synchronize with one another.
  However, the waiting flag is set on before the closing task
  ( CSOL ) is committed to issuing a wait.
  CSOL and the web-alias task are executing in parallel on
  different TCBs. The web-alias task completes the socket send
  and resets the in_send flag just before CSOL checks if socket
  I/O is in progress.
  When CSOL checks for socket I/O it discovers that none is in
  progress so skips around the suspend logic. Just before CSOL
  resets the waiting flag in the socket, the web-alias task
  checks this flag. As the flag is on, the web-alias resumes the
  suspend token held in the socket. This changes the state of the
  suspend token to RESUMED because there has been a RESUME without
  a corresponding SUSPEND.
  When CSOL tries to delete the suspend token, DFHDSSR detects the
  unexpected suspend token state and issues DFHDS0002 severe error
  code 0075.
  
  ADDITIONAL KEYWORDS :- DS0002
  

Problem conclusion

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

• DFHSOS03 routine soso_close_mainline has been changed so that
  the socket waiting flag is only set if the task issuing the
  close is committed to suspending.
  

APAR Information

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

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

  UK59280

Modules/Macros

•    DESSOSO  DFHSOSOC DFHSOS00 DFHSOS01 DFHSOS02
  DFHSOS03 DFHSOS04 DFHSOS05 DFHSOS06 DFHSOS07 DFHSOS08 DFHSOS09
  DFHSOS10 DFHSOS11 DFHSOS12 DFHSOS13 DFHSOS14 DFHSOS15 DFHSOS16
  DFHSOS17 DFHSOS18 DFHSOS19 DFHSOS20 DFHSOS21 DFHSOS22 DFHSOS23
  

Fix information

• Fixed component name

  CICSTS V3 Z/OS

• Fixed component ID

  5655M1500

Applicable component levels

• R400 PSY UK59280

     UP10/08/05 P F008

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.