PK42456: S0C4 IN DFHZLOC AT OFFSET 12B2 TRAN CLS1 07/09/19 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• DFHZCLS initiates CATD (label ZCLS_CATD_POS ) while DFHZGCN is
  waiting for the sessions to be unbound, causing the modegroup to
  be deleted beneath DFHZGCN's feet. When DFHZGCN wakes up out of
  its suspend, the value it has for TCATPTA is no longer valid, as
  it's been deleted already.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users with UK17910 applied.         *
  ****************************************************************
  * PROBLEM DESCRIPTION: Abend 0C4 in DFHZLOC at offset x'12B2'  *
  *                      followed by ZC0001 abend from DFHZGCN   *
  *                      at offset x'842' when CNOS CLOSE ALL    *
  *                      MODENAME is received on a user session. *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  A CNOS CLOSE ALL MODENAME is received on a user session.
  After CNOSing to zero the subroutine CLOSE_SNASVCMG frees the
  user session before suspending itself for 1 second to allow the
  CLSDST of the other user sessions to occur.
  
  As this connection is marked for deletion when released
  (TCSE_IMPLICIT_DELETE) a CATD transaction is attached and
  deletes the connection, freemaining the storage used for the
  modegroups and sessions.
  
  When the CNOS task resumes from the 1 second delay it attempts
  to check for ACQuired sessions in the user modegroup but fails
  with an 0C4 in DFHZLOC at offset x'12B2' because the storage has
  been reused. After the 0C4 abend has been taken, the recovery
  routine in DFHZGCN produces a second abend, ZC0001.
  
  Additional keywords
  msgDFHAP0001 msgDFHZC0001 PROCESS_SESSION_LIMIT CLOSE_SNASVCMG
  CLS1 CLR1
  

Problem conclusion

• UK17910
  The subroutine CLOSE_SNASVCMG in DFHZGCN has been amended to
  obtain the "TCT_NAMES.cccc" enqueue when it frees the user
  session, if the connection is due to be deleted when released
  (TCSE_IMPLICIT_DELETE).
  
  With the enqueue obtained CATD will not be able to start to
  delete the connection until the CNOS task completes.
  

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:

  PK52644 UK29876

Modules/Macros

•    DFHZGCN
  

Fix information

• Fixed component name

  CICSTS 3.1 Z/OS

• Fixed component ID

  5655M1500

Applicable component levels

• R400 PSY UK29876

     UP07/10/05 P F710

Fix is available

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