PK24304: SOS IN ECDSA DUE TO EXCESSIVE FRAB AND FLAB STORAGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• SOS in ECDSA due to a large number of orphaned FRABs and FLABs.
  These FRABs and FLABs are not currently associated with any task
  in the RM domain or FCP, and are not on the FC static storage
  free chains. The stranded FRABs are chained from FC_FRAB_CHAIN.
  .
  The problem occurs when the application issues an ENDBR without
  first issuing a STARTBR. DFHFCFR calls routine FIND_FRTE to look
  for the STARTBR FRTE. The FIND_FRTE routine does an inline RM
  call to find a FRAB, doesn't find one, so calls routine
  GET_FRAB to get one -- this is the FRAB that will get stranded.
  (A remote SYSID has been explicitly specified on the ENDBR).
  We also acquire a FLAB, but as we don't find a STARTBR FRTE,
  FCFR_UNKNOWN_REQID_ENDBR is set and we return an INVREQ to the
  application. The FRAB and FLAB are never placed on the FC static
  storage free chains for reuse, and CICS will eventually go SOS.
  .
  Additional keywords:
  FC_FRAB DFHFRAB FC_FLAB DFHFLAB UNKNOWN_REQID_ENDBR ENDBROWSE
  STARTBROWSE
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All.                                         *
  ****************************************************************
  * PROBLEM DESCRIPTION: Short on storage with DFHSM0133 issued. *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  In the reported problem, an application issued an ENDBR with a
  SYSID specified for a remote CICS system, with no corresponding
  STARTBR. The request failed with an INVREQ response.
  
  However, routine FIND_FRTE in DFHFCFR was driven and obtained a
  FRAB and a FLAB for the request despite the fact that no FRTE
  existed (because a STARTBR had not been issued). The FRAB was
  not registered with recovery manager and the FRAB and FLAB were
  never FREEMAIN'd. The application issued an inordinate number of
  these invalid ENDBR's and the CICS system eventually went short
  on storage.
  
  Keywords: SM0133 0133 msgDFHSM0133 WRITE MASSINSERT REWRITEE
  UNLOCK READPREV READNEXT RESETBR ENDBR FCFR_REPLACE
  FCFR_REPLACE_DELETE
  

Problem conclusion

• DFHFCFR has been modified and will no longer GETMAIN a FRAB
  and FLAB in the aforementioned scenario.
  

Temporary fix

•             *********
              * HIPER *
              *********
  FIX AVAILABLE BY PTF ONLY
  

Comments

APAR Information

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

  PK20946

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

  UK15488

Modules/Macros

•    DFHFCFR
  

Fix information

• Fixed component name

  CICSTS 3.1 Z/OS

• Fixed component ID

  5655M1500

Applicable component levels

• R400 PSY UK15488

     UP06/06/23 P F606

Fix is available

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