[open-cobol-list] bug report: SIGSEGV in GOBACK

[Matthew Fisher]

This report refers to the gnu-cobol-2.0 branch, checked out today from:

    svn://svn.code.sf.net/p/open-cobol/code/branches/gnu-cobol-2.0

Under certain conditions, a segmentation fault occurs on line 212 of
libcob/common.c.

A minimal test program (compiled with `cobc -xg test.cbl`):

       IDENTIFICATION DIVISION.
       PROGRAM-ID. test.

       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  CALL-STATUS  BINARY-LONG.

       PROCEDURE DIVISION.
           CALL "C$COPY"
               USING "test.cbl" "copy.cbl" "S"
               GIVING CALL-STATUS
           END-CALL

           GOBACK
           .

The output from running the program:

    test.cbl: 14 Attempt to reference unallocated memory (Signal
    SIGSEGV)
    Abnormal termination - File contents may be incorrect

Line 14 is the GOBACK statement. When run in gdb, with a breakpoint
set in cob_exit_common, it can be seen that the seg fault occurs on
the free statement in line 212 of libcob/common.c:

    if (cobglobptr->cob_term_buff) {
        free (cobglobptr->cob_term_buff);
    }