PH17862: CSOL ABEND 0C4 IN MODULE DFHSOLS / UI42764 AT OFFSET X'31DA' WHEN CICS IS AT MAXTASK. SOTUNING=YES IS CODED IN THE SIT.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• An HTTP TCPIPSERVICE using SOCKETCLOSE(000005) is open.
  The CICS region has entered MAXTASK condition with many
  tasks queued for MAXTASK.
  A client connection for the TCPIPSERVICE has been idle for
  5-seconds and is timed out by CICS.
  Timeout processing causes the asynchronous socket receive
  from 5-seconds earlier to be cancelled.
  The CICS socket listener task ( CSOL ) processes the
  cancelled receive and closes (and frees) the socket.
  This happens within the logic that deals with all asynchronous
  socket receive completions.
  After the socket has been deleted, code dealing with the
  SOTUNING SIT parameter executes. As CICS is at MAXTASK with
  a large queue of waiting tasks, the SOTUNING logic attempts to
  mark the socket for deletion.
  The socket is addressed from another socket object ( STE )
  which has also been freed. The pointer to the deleted socket
  is now garbage which leads to a program check.
  This causes the long running sockets listener task ( CSOL )
  to terminate abnormally. This means inbound socket requests
  will no longer be dealt with by the CICS region.
  CSOL should bypass the SOTUNING logic after a socket has been
  closed and deleted.
  Additional Symptoms:
  DFHSO0001 AN ABEND (CODE 0C4/AKEX) HAS OCCURRED
            IN MODULE DFHSOLS
  The region is a MAXTASK and SOTUNING YES is
  specified (which is the default). Code in DFHSOLS
  is trying to reference a STE, and has a bad address
  causing the program check.
  TCPIPSERVICE listener abend
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: Abend 0C4 in DFHSOLS when CICS is at    *
  *                      the MAXTASK limit.                      *
  ****************************************************************
  When CICS is at MAXTASK, SOTUNING logic in DFHSOLS attempts to
  set flag ste_socket_close in an STE pointed to by ste_ptr.
  However, the socket has been freed and ste_ptr now points to
  reused storage, causing an abend0C4.
  Keywords: S0C4 abendS0C4
  

Problem conclusion

• DFHSOLS has been changed to check that ste_ptr still points to
  an STE before trying to reference it.
  

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:

  UI67663 UI67664 UI67665

Modules/Macros

• DFHSOLS
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R000 PSY UI67663

     UP20/02/01 P F001 ¢

• R100 PSY UI67664

     UP20/02/01 P F001 ¢

• R200 PSY UI67665

     UP20/02/01 P F001 ¢

Fix is available

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