PH63907: NEW FUNCTION: COMPILER OPTION LSACHECK (LINKAGE SECTION ADDRESS CHECK)

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• -
  

Local fix

• -
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of Enterprise COBOL V6 who want a      *
  *                 way to detect references to LINKAGE SECTION  *
  *                 data items that have not had addressability  *
  *                 set.  This is the "Zero Address" problem     *
  *                 that is also helped by the z/OS Zero Address *
  *                 Detection feature, but this COBOL feature    *
  *                 causes programs that reference LINKAGE       *
  *                 SECTION items with no addressability to      *
  *                 ABEND, you don't have to wait for the ZAD    *
  *                 report.  The COBOL feature is activated via  *
  *                 the new LSACHECK compiler option.            *
  ****************************************************************
  * PROBLEM DESCRIPTION: Some users find that they have programs *
  *                      that reference LINKAGE SECTION items    *
  *                      that have not had addressability set.   *
  *                      These programs can behave differently   *
  *                      when migrating to z/OS 2.5 or 3.1       *
  ****************************************************************
  * RECOMMENDATION: Apply the provided PTF and recompile         *
  *                 programs with the LSACHECK compiler option   *
  ****************************************************************
  There have been several reports of COBOL users getting different
  results from their applications after migrating to a new release
  of z/OS, either z/OS 2.5 or 3.1.  This is because these
  applications had programs referencing LINKAGE SECTION data items
  whose addressability had not been set.  These data items were
  referencing "low core" or addresses in the x'0000' to x'1000'
  range.  The data in those addresses has not changed in many
  years, but was changed starting with z/OS 2.5, which caused
  a change in behavior in some of these programs. There was no
  way to prevent such programs from making changes to databases or
  files, so COBOL is providing this solution.
  
  ZOS0203T/K ZOS0204T/K ZOS0205T/K ZOS0301T/K
  

Problem conclusion

Temporary fix

Comments

• The LSACHECK compiler option is added to the COBOL compiler.
  This option will cause any references to LINKAGE SECTION items
  with no addressability established to ABEND with an S0C4.
  This feature has no effect on performance. While initialization
  code normally sets the BLLs (addresses for LINKAGE SECTION
  items) to zero, with LSACHECK the BLLs are set to x'7FFFF000'.
  This corresponds to a page in z/OS that has no storage backing
  it, so any reference to this page (read or write) will cause a
  0C4 ABEND.
  Properly written programs will not see any change (they also
  would not have had any difference in behavior when migrating to
  z/OS 2.5 or later) unless comparing the ADDRESS OF a LINKAGE
  SECTION item to NULL. For those cases, the code also needs to
  compare the address to x'7FFFF000'.
  
  There are COBOL Runtime APARs that improve upon
  LSACHECK feature by providing a new runtime message for
  ABENDs due to LSACHECK, to better explain the 0C4 ABEND.
  There is no dependency between the compiler LSACHECK APAR
  and the runtime message support for LSACHECK APAR.
  The run time APARs are:
  PH63898 for 31-bit/AMODE31
  PH63939 for 64-bit/AMODE64
  

APAR Information

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

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

  PH64491

Modules/Macros

• IGY8RWTU IGYCASMB IGYCCBE  IGYCCCRT IGYCCICS IGYCCSRV IGYCDGEN
  IGYCDIAG IGYCDMAP IGYCEN$0 IGYCEN$1 IGYCEN$2 IGYCEN$3 IGYCEN$4
  IGYCEN$5 IGYCEN$8 IGYCEN$D IGYCEN$R IGYCFGEN IGYCFREE IGYCINIT
  IGYCJA$0 IGYCJA$1 IGYCJA$2 IGYCJA$3 IGYCJA$4 IGYCJA$5 IGYCJA$8
  IGYCJA$D IGYCJA$R IGYCLIBR IGYCLSTR IGYCLVL0 IGYCLVL1 IGYCLVL2
  IGYCLVL3 IGYCLVL8 IGYCMALL IGYCOPI  IGYCOPT  IGYCOSCN IGYCPGEN
  IGYCRCTL IGYCRDPR IGYCRDSC IGYCREAL IGYCRWT  IGYCSCAN IGYCSIMD
  IGYCUE$0 IGYCUE$1 IGYCUE$2 IGYCUE$3 IGYCUE$4 IGYCUE$5 IGYCUE$8
  IGYCUE$D IGYCUE$R IGYCXREF IGYDRV   IGYEQCWI IGYMSGE  IGYMSGK
  IGYMSGT  IGYQCBE  IGYQSPLT IGYZQEN6 IGYZQENU IGYZQJP6 IGYZQJPN
  

Fix information

• Fixed component name

  ENT COBOL FOR Z

• Fixed component ID

  5655EC600

Applicable component levels

• R630 PSY UI99158

     UP24/12/03 P F412  

• R631 PSY UI99159

     UP24/12/03 P F412  

• R632 PSY UI99160

     UP24/12/03 P F412  

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.