PM95132: ONLINE CHANGE FOR ACBLIB WHILE DC MONITOR IS EXECUTING CAUSES AN S0C4 IN DFSMNTR0(PM16421)+X'12DC LABEL SL87030

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• An S0C4 occurs when the DC monitor is running and an online
  change for ACBLIB is done. DFSMNTR0 is processing a list of area
  DMACs. The problem is the code hit a part of the list where the
  DMAC storage has been freed and the list has not been updated
  with the new addresses. ABEND S0C4 in DFSMNTR0(PM16421)+x'12DC
  label SL87030.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: IMS Fast Path V12 users of ACB member        *
  *                 online change and IMS monitor utility.       *
  ****************************************************************
  * PROBLEM DESCRIPTION: If Online Change for ACBLIB is running  *
  *                      while IMS Monitor is running, an        *
  *                      ABENDS0C4 occurs.                       *
  ****************************************************************
  * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
  ****************************************************************
  When the IMS Monitor is running at the same time as online
  change for ACBLIB, an ABENDS0C4 can occur in DFSMNTR0. Module
  DBFOLC01 frees the DMAC storage during the online change path.
  
  There is a timing window after the DMAC storage has been freed
  by DBFOLC01 but before module DBFOLC02 rebuilds the arealist
  where module DFSMNTR0 for the IMS Monitor references the DMAC
  that has been freed. Its this window that exposes the potential
  for the ABEND0C4 to occur.
  
  This problem can occur while either Member OLC and/or OLC
  involving ACBLIB is running.
  
  
  Additional Keywords: DC Monitor DCMON IMSDCMON 0C4 S0C4
  

Problem conclusion

• GEN:
  KEYWORDS:
  
  *** END IMS KEYWORDS ***
  Logic has been added to the following:
  
  DFSMNTR0: Logic has been added to acquire the DBFALOCK if it is
  available under conditional share mode. If DBFALOCK is not
  available, skip the DFSSLOG 87 call. If the latch is acquired,
  DBFALOCK is released after the DFSSLOG 87 call.
  
  DBFALOCK: Logic has been added for Conditional Share Mode. Under
  the conditional share mode, if the latch is available, get the
  latch. If the latch is not available, do not wait for it to be
  available and do not acquire the latch.
  
  For exclusive mode, get latch only if latch is not already
  owned by online change.
  
  DBFOLC01: Get DBFALOCK exclusive before we free DMCB in DMACs.
  
  DBFOLC02: Recompile to obtain the new changes added to DBFALOCK.
  
  DFSICV30: Logic was added to acquire the latch in DBFOLC15.
  
  DFSMOLS0: Logic was added to not acquire the latch in DBFOLC15.
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

  PM65936

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

  PM95133 UI12317 UI12318

Modules/Macros

•    DBFALOCK DBFOLC01 DBFOLC02 DFSICV30 DFSMNTR0
  DFSMOLS0
  

Fix information

• Fixed component name

  IMS V12

• Fixed component ID

  5635A0300

Applicable component levels

• R200 PSY UI12317

     UP13/11/12 P F311 Ž

• R201 PSY UI12318

     UP13/11/12 P F311 Ž

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.