PM16899: ABEND0C1 AFTER APPLYING APAR PK91585 TCB SWITCH NOT TAKING PLACE 10/06/23 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Bug in code against APAR PK91585.
  The last change mode below, should have switched back to the QR
  TCB. When the initial change mode is issued from the QR to the
  RO, the field OLD_MODE, which is located in the kernel stack,
  would remember it was on the QR TCB.
  This APAR added code to issue the second and third CHANGE_MODEs
  around the SVC call (offset x'3a2a and x'3A66' in DFHLDLD1,
  respectively).
  Since we were already running on the RO TCB, this code changed
  the contents of OLD_MODE to the  RO TCB.
  Now later, when LDLD is finished, it does the change_mode that
  should switch back to the QR, but since OLD_MODE now reflects
  the RO TCB. No switch takes place leaving the task running
  on the RO TCB.
  

Local fix

• *
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS Transaction Server V4.1 for z/OS    *
  *                 customers who have applied APAR PK98411.     *
  ****************************************************************
  * PROBLEM DESCRIPTION: If a REFRESH_PROGRAM is performed on    *
  *                      a program that resides in a PDSE then   *
  *                      CICS will switch to the RO TCB twice.   *
  *                      This causes CICS to forget the          *
  *                      original TCB information and so cannot  *
  *                      switch back.                            *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When CICS processes a REFRESH_PROGRAM call for a program
  residing in a PDSE, CICS changes mode twice to the RO TCB
  overwriting the saved old mode value with RO and thus not being
  able to change back to the original mode.
  This results in the abendS0C1.
  
  Keywords:
  S0C1 0C1
  

Problem conclusion

• UK52226
  
  DFHLDLD1 and DFHLDDMI have been changed to ensure that a change
  to the RO only takes place if CICS is not already running on the
  RO.
  

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

APAR Information

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

  PM16131

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

  UK59344

Modules/Macros

•    DFHLDCOM DFHLDDMI DFHLDLD1 DFHLDLD2
  

Fix information

• Fixed component name

  CICS TS Z/OS V4

• Fixed component ID

  5655S9700

Applicable component levels

• R600 PSY UK59344

     UP10/08/07 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.