Re: [Nmh-workers] GCC 8 pre-releases have escaped...

[Ralph Corderoy]

Hi Ken,

> I ran it against 500k messages on the Enron corpus ... and of course
> YOU have the one email that breaks it.  Sigh.

:-)  Here's the first complaint.

    $ uip/scan -version
    scan -- nmh-1.7+dev 1.7-branchpoint-490-g42db3a2c built 2018-02-10 17:21:09 
+0000 on orac
    $ valgrind uip/scan prev cur

        ==12501== Invalid write of size 1
        ==12501==    at 0x116DA6: m_getfld (m_getfld.c:711)
         711                         *cp++ = c;
        ==12501==    by 0x10DCED: scan (scansbr.c:181)
         181         bufsz = rlwidth, state = m_getfld (&gstate, name, tmpbuf, 
&bufsz, inb)) {
        ==12501==    by 0x10D542: main (scan.c:282)
        ==12501==  Address 0x54c84b0 is 0 bytes inside a block of size 8,192 
free'd
        ==12501==    at 0x4C2E10B: free (vg_replace_malloc.c:530)
        ==12501==    by 0x113008: fmt_scan (fmt_scan.c:1158)
        1158                             free (comp->c_text);
        ==12501==    by 0x10DAD2: scan (scansbr.c:338)
         338     fmt_scan (fmt, *scanl, slwidth, dat, NULL);
        ==12501==    by 0x10D542: main (scan.c:282)
        ==12501==  Block was alloc'd at
        ==12501==    at 0x4C2CEDF: malloc (vg_replace_malloc.c:299)
        ==12501==    by 0x11ABC7: mh_xmalloc (utils.c:47)
        ==12501==    by 0x10E00B: scan (scansbr.c:143)
         143             *nxtbuf++ = mh_xmalloc(rlwidth);
        ==12501==    by 0x10D542: main (scan.c:282)
        ==12501==

Without valgrind, the command appears to function just fine.
valgrind doesn't find fault with this one.

    $ /bin/scan -version
    scan -- nmh-1.7+dev 1.7-branchpoint-443-g47b86722 built 2017-11-26 18:38:47 
+0000 on orac

To get the abort, I ditch valgrind and get a backtrace from gdb.

    #0  0x00007ffff7829860 in raise () from /usr/lib/libc.so.6
    #1  0x00007ffff782aec9 in abort () from /usr/lib/libc.so.6
    #2  0x00007ffff786c437 in __libc_message () from /usr/lib/libc.so.6
    #3  0x00007ffff787278b in malloc_printerr () from /usr/lib/libc.so.6
    #4  0x00007ffff78744f0 in _int_free () from /usr/lib/libc.so.6
    #5  0x000055555555ef4a in fmt_scan (format=<optimized out>, 
scanlp=<optimized out>, width=114, 
        address@hidden <dat>, address@hidden) at sbr/fmt_scan.c:1134
    #6  0x0000555555559ad3 in scan (inb=<optimized out>, innum=5785, outnum=0, 
nfs=<optimized out>, 
        width=<optimized out>, curflg=<optimized out>, unseen=0, 
folder=0x5555555a5a00 "inbox", size=0, noisy=1, 
        scanl=0x7fffffffbdb8) at uip/scansbr.c:338
    #7  0x0000555555559543 in main (argc=<optimized out>, argv=<optimized out>) 
at uip/scan.c:282

I suspect it's all related and the `free (comp->c_text)' above is key.

-- 
Cheers, Ralph.
https://plus.google.com/+RalphCorderoy