Re: [htdig] 'Segmentation fault' runing htdig on a Cobalt Raq server


Gilles Detillieux (grdetil@scrc.umanitoba.ca)
Mon, 9 Aug 1999 14:08:27 -0500 (CDT)


According to Tomas Garcia Ferrari:
> >It would help significantly if you could run gdb on the core file like so:
> >
> >gdb htdig core
> >...
> >
> >You'll then get a (gdb) prompt. Type 'bt' to give us a backtrace.
>
> Hi,
>
> This is the result:
> ---
> [root@cobalt1 bin]# gdb htdig core
> GNU gdb 4.17
> Copyright 1998 Free Software Foundation, Inc.
> GDB is free software, covered by the GNU General Public License, and you
> are
> welcome to change it and/or distribute copies of it under certain
> conditions.
> Type "show copying" to see the conditions.
> There is absolutely no warranty for GDB. Type "show warranty" for
> details.
> This GDB was configured as "mipsel-redhat-linux"...
> Core was generated by `./htdig -c
> /usr/local/htdig/conf_akademie/akademie_d.conf
> '.
> Program terminated with signal 11, Segmentation fault.
> find_solib: Can't read pathname for load map: Input/output error
>
> #0 0x0 in ?? ()
> (gdb) bt
> #0 0x0 in ?? ()
> warning: Hit heuristic-fence-post without finding
> warning: enclosing function for address 0x2ac3d130
> This warning occurs if you are debugging a function without any symbols
> (for example, in a stripped executable). In that case, you may wish to
> increase the size of the search with the `set heuristic-fence-post'
> command.
>
> Otherwise, you told GDB there was a function where there isn't one, or
> (more likely) you have encountered a bug in GDB.
> (gdb) bt
> #0 0x0 in ?? ()
> warning: Hit heuristic-fence-post without finding
> warning: enclosing function for address 0x2ac3d130
> (gdb) quit
> ---
>
> Could you give me some help understanding this?

This wasn't very meaningful output from gdb. There are a few possible
reasons for this:

1) Memory got so messed up before the segmentation fault, that the core
dump is unusable.

2) The core dump is not actually from htdig, but rather from another of
the programs in the ht://Dig package, e.g. htfuzzy.

3) You didn't give the right pathname to gdb for either the htdig
executable or the core file.

4) The htdig executable has no debugging information or symbol table left.

First of all, which version of ht://Dig are you running? If it's not
3.1.2, please try that version first. Next, make sure there's a -g
option in the CXXFLAGS definition in Makefile.config, after running
/configure in the source directory. If it's not there, add it and run
"make clean; make".

When you have the current version built, with debugging information
included, then try running htdig from gdb. E.g., if you're in the main
source directory for htdig-3.1.2, try:

        gdb htdig/htdig
        (GNU gdb messages)
        run -vsic /usr/local/htdig/conf_akademie/akademie_d.conf

and if this gives a segmentation fault, try the "bt" command then to
see if it gives more meaningful output. If htdig runs successfully this
way, try running htmerge, htnotify and htfuzzy until you determine which
program is failing.

-- 
Gilles R. Detillieux              E-mail: <grdetil@scrc.umanitoba.ca>
Spinal Cord Research Centre       WWW:    http://www.scrc.umanitoba.ca/~grdetil
Dept. Physiology, U. of Manitoba  Phone:  (204)789-3766
Winnipeg, MB  R3E 3J7  (Canada)   Fax:    (204)789-3930

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