PK21254: /DISPLAY ACTIVE SHOWS DEPENDENT REGION ACTIVE-DBCMD. ITASK WAITSIN DFSYFD00.

APAR status

• Closed as program error.

Error description

• IMS dependent region is hung with status active-dbcmd. The
  region has actually been in an IWAIT for several hours but
  recently a DBR command was issued for a DB that it has intent.
  The module flow for the ITASK was:
  DFSFXC30,DFSDLA30,DLA3LUMI,DFS6LUS0,DFSYLUS0,DFSYFD00,DFSIWAIT.
   Dfsyfd00 has enqueued an AWE to be processed by DFSYMOM0. There
  is also another ITASK in this identical IWAIT and the 2 AWE
  blocks they own are chained together but the Queue header for
  DFSYMOM0 indicates there is no work to do.
    These AWE blocks have been orphaned and there is no way to
  continue these regions for processing.
    An examination of the code in DFSYMOM0 shows an incorrect
  order where an ITASK that is waiting for an AWE to complete
  processing is posted. After the post is done DFSYMOM0
  references the AWE again to obtain the AWENXT pointer. This is
  not acceptable as that AWENXT pointer could be changed if the
  AWE caller is responsible for doing the storage free for the
  AWE. This could cause the Next awe on the chain to be
  orphaned.
  Additional Symptom: S878-18 DFSYSTO0 bad AWE
  address passed from DFSYMOM0 to DFSYSTO0.
  Kevin Stewart 08/14/2006
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All IMS R910 users of OTMA                   *
  ****************************************************************
  * PROBLEM DESCRIPTION: IMS MPP(s) hung with status             *
  *                      ACTIVE-DBCMD                            *
  ****************************************************************
  * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
  ****************************************************************
  DFSYFD00 has enqueued an AWE to be processed by DFSYMOM0.
  DFSYMOM0 could be a victim of a timing problem if the
  next AWE pointer field is referenced right after an IPOST of
  an ECB that will ultimately delete/change the AWE itself.
  Also, due to the AWE chain being broken AWEs may become
  orphaned.
  

Problem conclusion

• AIDS: RIDS/UTIL RIDS/DBS DBS/UTIL
    DEP: NONE
    GEN:
  
  *** END IMS KEYWORDS ***
  Logic has been changed to reference/use AWE fields before
  performing any post that could result in a change
  of the AWE itself.
  

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:

  UK14177

Modules/Macros

• DFSYMOM0
  

Fix information

• Fixed component name

  IMS V9

• Fixed component ID

  5655J3800

Applicable component levels

• R900 PSY UK14177

     UP06/05/12 P F605 Ž