PI65370: MEMORY OVERLAY WHEN LOADING AND STORING BIT FIELD

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Loading and storing values from a bit field struct is causing a
  memory write overlay on memory past the end of the bit field.
  The issue occurs when loading and storing 4 bytes when only 3
  bytes should be updated.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: USERS THAT HAVE A BIT FIELD OF THREE BYTES   *
  *                 OCCUPYING THE LAST THREE BYTES OF A BIT      *
  *                 FIELD CONTAINER. FOR EXAMPLE:TYPEDEF STRUCT  *
  *                 {  UNSIGNED   BF1:6;  UNSIGNED   BF2:2;      *
  *                 UNSIGNED   BF3:24;} A;                       *
  ****************************************************************
  * PROBLEM DESCRIPTION: THE COMPILER IS EMITTING A LOAD/STRORE  *
  *                      INSTRUCTION STARTING AT OFFSET 1 THUS   *
  *                      ACCESSING THE BYTE FOLLOWING THE BIT    *
  *                      FIELD. IN MOST CASES THIS DOES NOT      *
  *                      CAUSE A PROBLEM SINCE THE BYTE          *
  *                      FOLLOWING THE BIT FIELD IS UPDATED      *
  *                      WITH THE SAME CONTENT IT ALREADY HAS,   *
  *                      BUT WHEN THE BIT FIELD IS AT THE END    *
  *                      OF THE ADDRESS SPACE OR AT THE END OF   *
  *                      THE PAGE THIS PRODUCES AN 0C4 ABEND.    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  THE COMPILER IS PRODUCING BAD CODE FOR SOURCES WITH BIT FIELDS.
  

Problem conclusion

• APPLY PROVIDED FIX.
  

Temporary fix

Comments

APAR Information

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

  PI64727

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

Modules/Macros

•    CCNEP
  

Fix information

• Fixed component name

  C/C++ FOR MVS

• Fixed component ID

  56551210A

Applicable component levels

• R790 PSY UI39212

     UP16/09/02 P F609

Fix is available

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