OA29512: ABEND0A9 RC FF09 BY ISTPVCDV CALLED BY ISTDRDDP

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Module ISTPVCDV takes ABEND0A9 RC FF09 when called by
  ISTDRDDP to allocate a VWA extension. The base VWA and the
  maximum number of allowed VWA extensions have been filled due to
  recursive calls in module ISTDRDDP. ISTDRDDP is trying to
  delete a Directory Entry Control Block (DECB) that points to
  itself as a parent node and that also includes itself as the
  only node on its list of child nodes.
  Secondary symptoms:  ABEND0C4 in various VTAM modules including
  ISTTRCLT, ISTNRCTR, and ISTACCNS due to overlays of VTAM
  private storage that occur beyond the end of each filled
  VWA extension. There may be many of these ABEND0C4s
  repeated in rapid succession, and they may not occur until
  long after the original ABEND0A9 in ISTPVCDV. Each time
  ISTDRDDP is called by itself, it calls module ISTTRCLT which in
  turn calls module ISTNRCTR. When ISTTRCLT's save area reaches
  the bottom of each VWA extension, the call to ISTNRCTR causes
  ISTNRCTR to use storage beyond the end of the VWA for its save
  area. This causes corruption of any VTAM data structures that
  may exist in the storage beyond the end of the VWA.  Examples
  of overlaid storage seen so far have included IP Address
  (IPADR) control blocks and DECBs.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All using APPN Network Nodes.                *
  ****************************************************************
  * PROBLEM DESCRIPTION:   ABEND0A9 RC FF09 issued by ISTPVCDV,  *
  *                      which was called by ISTDRDDP.  This     *
  *                      could be followed by ABEND0C4s in       *
  *                      various VTAM modules including          *
  *                      ISTTRCLT, ISTNRCTR, and ISTACCNS.       *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
        NETA.BN1---/---NETB.NN2
            |              |
            |              |
            +------/---NETB.NN3
  
    In the above INVALID configuration, an ABEND0A9 RC FF09 was
  issued by ISTPVCDV in NETA.BN1 as the result of an attempt to
  expand a VWA more times than it was allowed to be expanded.  In
  this case, ISTPVCDV was called by ISTDRDDP.
    ISTDRDDP was called by the DBDELETE macro to delete a
  resource from the DS database.  As part of that process, any
  resources on the node's Child List need to be deleted.  In this
  case, NN2 in the above configuration was to be deleted, but it
  was also on its own child list.  It is not valid for a node to
  be on its own child list.
    This invalid child list caused ISTDRDDP to issue another
  DBDELETE for NN2.  This caused ISTDRDDP to be called recursively
  to delete NN2.  Each time this happened, a section of the VWA
  was used for ISTDRDDP.  This led to the ABEND0A9 in ISTPVCDV.
    This APAR will address ISTDRDDP trying to delete a node from
  its own child list.  We were not able to determine how NN2 got
  put on its own child list, but believe it is related to the
  invalid configuration.  The configuration is invalid because a
  peripheral subnetwork is not allowed to have more than one
  connection to another network.  In this case NETB.NN2 was
  connected to NETA directly through NETA.BN1 and also through
  NETB.NN3.
    An additional symptom of ISTDRDDP being called recursively and
  exceeding the VWA expansion is possible ABEND0C4s in various
  modules including ISTTRCLT, ISTNRCTR, and ISTACCNS, due to
  overlays of VTAM private storage that occur beyond the end of
  each filled VWA extension. There may be many of these ABEND0C4s
  repeated in rapid succession, and they may not occur until long
  after the original ABEND0A9 in ISTPVCDV.
  

Problem conclusion

• ISTDRDDP has been changed to not issue a DBDELETE for a
  resource on a node's DECB_CHILD_LIST if it is the same node that
  is currently being processed.  If this occurs, ISTDRDDP will
  issue a CPRC with sense 081C0002, software error - no retry,
  and use the LSTREM function to remove the DECB from its own
  child list.
    This fix is only needed on Network Nodes.
  

Temporary fix

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

Comments

APAR Information

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

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

  UA48929 UA48930 UA48931 VM64851 DY47182

Modules/Macros

• ISTDRDDP
  

Fix information

• Fixed component name

  VTAM V4 MVS/ESA

• Fixed component ID

  569511701

Applicable component levels

• R1A0 PSY UA48929

     UP09/08/19 P F908

• R1B0 PSY UA48930

     UP09/08/19 P F908

• R190 PSY UA48931

     UP09/08/19 P F908

Fix is available

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