PH50667: QSAM file initialization may be repeatedly driven, leaking I/O related blocks DCB and DCBE for AMODE64

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• In the LP(64) environment, if a compile unit containing QSAM
  file definitions is repeatedly entered, parts of QSAM file
  initialization are also repeated--they should only be done on
  first entry. This leaks DCBs (data control blocks), which reside
  below the line where a leak is likely to have adverse outcomes.
  DCBEs (data control block extensions) are also leaked, but being
  above the line, they have a lesser impact.
  
  Note that a typical file reading mainline compile unit is
  unaffected by this issue because it is only entered once.
  

Local fix

• In some contexts, the file use can be isolated in a separate
  module that's entered only once.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of Enterprise COBOL 6.3 and later      *
  *                 releases running AMODE 64 COBOL programs     *
  *                 which have QSAM or VSAM I/O.                 *
  ****************************************************************
  * PROBLEM DESCRIPTION: When an application calls               *
  *                      a COBOL program running in AMODE 64     *
  *                      with QSAM or VSAM I/O such as OPEN,     *
  *                      READ, or CLOSE and is called multiple   *
  *                      times, the application might abend or   *
  *                      terminate with unexpected behavior      *
  *                      due to out of BELOW THE LINE storage.   *
  *                                                              *
  *                      At times, the BELOW THE LINE storage    *
  *                      shortage results in abend occurred      *
  *                      from COBOL Runtime entry                *
  *                      'initOneQSAMFile'+X'4E0'                *
  *                      in CELQV004 module with the following   *
  *                      traceback.                              *
  *                                                              *
  *                      ...                                     *
  *                      initOneQSAMFile +000004E0 [abend]       *
  *                      IGZQIFCB +0000087E [calls               *
  *                      initOneQSAMFile]                        *
  *                      IGZQPRS2 +0000031A [calls IGZQFICB]     *
  *                      ...                                     *
  *                      main                                    *
  ****************************************************************
  * RECOMMENDATION: Install the provided PTF.                    *
  ****************************************************************
  The AMODE 64 COBOL run-time routine unconditionally created
  new I/O DCB (Data control block) and DCBE (Data Control Block
  Extension) repeatedly for each time the COBOL program was
  called. Eventually It caused BELOW THE LINE storage shortage.
  
  volume.
  
  COB0603T/K COB0604T/K
  

Problem conclusion

• The COBOL Runtime logic has been fixed. I/O DCB and DCBE are
  conditionally created and reused.
  

Temporary fix

Comments

APAR Information

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

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

  UI83417 UI83418

Modules/Macros

• CELQSG04 CELQV004 IGZQAPI  IGZQCA64 IGZQCDA  IGZQINPL IGZQJNI2
  

Fix information

• Fixed component name

  LE ENT COBOL LI

• Fixed component ID

  568819812

Applicable component levels

• R7C0 PSY UI83417

     UP22/12/01 P F211

• R7D0 PSY UI83418

     UP22/12/01 P F211

Fix is available

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