PK99205: IPCONN STUCK IN FREEING STATE AFTER THE DFHIS1022 MESSAGE IS ISSUED

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• When the DFHIS1022 is issued, the CISE error processing task
  will loop through all the mirror tasks attempting to purge
  them. The vast majority of these will abend, send various
  error responses back to CTG and free off their receive
  sessions. However some of them do not.
  The most recently attached mirror tasks are still waiting
  for initial dispatch. That means the ISSB_STATE in the
  sessions for each of these mirrors is set to IS_RECEIVE.
  Normally, the RECEIVE_REQUEST would flip the ISSB_STATE to
  IS_SEND, but this doesn't happen because of the PURGE.
  Since the ISSB_STATE is not ISSB_SEND, DFHISIS bypasses the
  DFHISZA SEND_ERROR call and also the skips dfhisis_free_issb.
  This leaves the IPCONN in a freeing state.
  Additional Symptom(s) Search Keyword(s): KIXREVDAM
  DFHIS1023 DFHIS1022 061D free
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All                                          *
  ****************************************************************
  * PROBLEM DESCRIPTION: IPCONN for CICS Transaction Gateway     *
  *                      left in freeing state following         *
  *                      DFHIS1022.                              *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  A condition developed where the limit of available sessions for
  a CICS Transaction Gateway IPCONN was reached. As mirror tasks
  started to terminate and send their final flows to the gateway,
  CTG started to send new requests to CICS. CICS was unable to
  allocate a new session for one of these requests because
  terminating mirror tasks had not released their sessions back to
  the free pool. This initially produced message DFHIS1023 and an
  error response was sent to CTG using the single system session
  which exists for the CTG IPCONN.
  While the DFHIS1023 error was being processed using the only
  system session, another request arrived from CTG.
  The IPCONN was still at the session limit and this time the
  system session was unavailable. This caused a connection error
  to be queued to the CISE error processing task.
  CISE issued message DFHIS1022 - error code 061D. CISE now put
  the IPCONN into FREEING state and issued a series of PURGE
  requests against mirror tasks associated with the IPCONN. The
  ISSB_PURGED flag was set in the session blocks owned by the
  mirror tasks for every PURGE which was accepted. Most of these
  mirror tasks abended and released their sessions back to the
  IPCONN session pool.
  However, some mirror tasks failed to release their session
  blocks during abend processing which left the IPCONN stuck in
  a FREEING state.
  The mirror tasks which failed to release their sessions had all
  been attached just before the session limit was hit and were all
  awaiting initial dispatch. The sessions for these mirror tasks
  all had an ISSB_STATE of IS_RECEIVE.
  This state would normally change to IS_SEND during transaction
  initialization. However, the ISSB_PURGED flag causes the
  DFHISIS INITIALIZE_RECEIVER call to fail with a PURGED response
  and the ISSB_STATE was left as IS_RECEIVE.
  Later on these mirror tasks called DFHISIS function SEND_ERROR.
  SEND_ERROR should release the session after sending an IS7
  error response to CTG.
  However, the ISSB_STATE of IS_RECEIVE caused DFHISIS SEND_ERROR
  processing to be abandoned and the session was never freed.
  
  ADDITIONAL KEYWORDS :- MSGDFHIS1022 MSGDFHIS1023 061D
  

Problem conclusion

• DFHISSR has been changed to complete RECEIVE_REQUEST processing
  for the initial receive by a mirror task when the ISSB_PURGED
  flag is on providing the HTTP session is still usable.
  

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

APAR Information

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

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

  PM01878 UK52939

Modules/Macros

•    DESISSR  DFHISSR
  

Fix information

• Fixed component name

  CICSTS V3 Z/OS

• Fixed component ID

  5655M1500

Applicable component levels

• R500 PSY UK52939

     UP09/12/21 P F912

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.