PH70599: ABEND0C4 IN DFHDSAT WHEN DISASSOCIATE(YES) IS SPECIFIED ON A CALL FOR A NON-OPEN TCB. 26/04/30 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• An Abend 0C4 occurs in DFHDSAT when issuing a change mode from
  an NON-OPEN TCB with DISASSOCIATE parameter set to YES.
  
  DFHDS0001 GAL95900 An abend (code 0C4/AKEX) has occurred at
  offset X'5C30' in module DFHDSAT.
  
  
  In this error scenario the call to DFHDSAT for the CHANGE_MODE
  is made from DFHSOMG when attempting to switch back to the
  callers TCB after closing a socket in a socket pool. This code
  path is driven when the CICS region is at MAXSOCKETS and an
  available socket in a socket pool is being reclaimed to  be
  reused for the incoming HTTP request.
  
  The abend occurs when this change_mode is for a NON-OPEN TCB
  because the DISASSOCIATE parameter is not relevant for OPEN
  TCBs.  The change mode itself is successful, the 0C4 happens
  while attempting to free what DS assumes is an open TCB because
  disassociated_tcb has been specified.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS Users with PTF UO05733, UO05734     *
  *                 or UO05735 applied.                          *
  ****************************************************************
  * PROBLEM DESCRIPTION: Abend 0C4 occurs in DFHDSAT after       *
  *                      a CHANGE_MODE call is made for a        *
  *                      non-OPEN TCB.                           *
  ****************************************************************
  When a CICS region is at MAXSOCKETS and in the process of
  reclaiming an available socket from a socket pool to be reused
  for the incoming HTTP request, an 0C4 can be seen following the
  CHANGE_MODE issued to switch back to the callers TCB after
  closure of the socket from the pool.
  This occurs when the CHANGE_MODE is issued for a non-OPEN TCB,
  this is due to the CHANGE_MODE call always specifying the
  DISASSOCIATE_TCB parameter as YES. This parameter is not
  relevant for non-OPEN TCBs.
  
  The CICS trace will show an EXCEPTION trace entry similar to the
  following:
  
  DS 0052 DSAT  *EXC* - DSAT_RECOVERY - FUNCTION(CHANGE_MODE)
   TCB_TOKEN(299F8C00 , 00000001) DISASSOCIATE_TCB(YES)
  

Problem conclusion

• UO05733, UO05734, UO05735
  
  CICS has been updated to only specify DISASSOCIATE_TCB(YES)
  when the CHANGE_MODE is issued for an OPEN TCB.
  

Temporary fix

Comments

APAR Information

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

  PH70536

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

  UO07650 UO07651 UO07652

Modules/Macros

• DFHSOAD  DFHSOCK  DFHSODM  DFHSODUF DFHSOIS  DFHSOL   DFHSOLI
  DFHSOLS  DFHSOLX  DFHSOLX6 DFHSOM01 DFHSOM02 DFHSOM03 DFHSOPL
  DFHSOPLT DFHSORD  DFHSOS00 DFHSOS01 DFHSOS02 DFHSOS03 DFHSOS04
  DFHSOS05 DFHSOS06 DFHSOS07 DFHSOS08 DFHSOS09 DFHSOS10 DFHSOS11
  DFHSOS12 DFHSOS13 DFHSOS14 DFHSOS15 DFHSOS16 DFHSOS17 DFHSOS18
  DFHSOS19 DFHSOS20 DFHSOS21 DFHSOS22 DFHSOS23 DFHSOSE  DFHSOST
  DFHSOTB  DFHSOTI  DFHSOTRI DFHSOUE  DFHSOXM  DFHWBCL  DFHWBSC
  DFHWBUR
  

Fix information

• Fixed component name

  CICS TS Z/OS V6

• Fixed component ID

  5655YA100

Applicable component levels

• R400 PSY UO07652

     UP26/05/02 I 1000 {

• R500 PSY UO07651

     UP26/05/01 P F604 {

• R600 PSY UO07650

     UP26/05/01 P F604 {

Fix is available

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