[TriLUG] Apache: Segmentation fault errors

[Robert Dale]

http://httpd.apache.org/dev/debugging.html

On 3/7/07, Paul G. Szabady <Paul at thyservice.com> wrote:
> James,
>
> OK, I give up.  How can I make apache dump core?  I'm not finding anything
> valuable through google.  :(
>
> --
> Paul
> @ Thy Service
>
> > On 3/4/07, Paul G. Szabady <Paul at thyservice.com> wrote:
> >> Greetings,
> >>
> >> I was wondering if anyone had any good pointers for trouble-shooting
> >> Apache Segmentation fault errors on linux.
> > It doesn't matter the application if you are getting a seg fault, look
> > at the core file with gdb.  If you are not dropping cores configure
> > your box to do so (actually with the 2.6 kernel you can configure
> > where cores drop, a really nice feature [solaris had something
> > similar]).  Anyway once you have a readable core file type something
> > like:
> >
> >    gcb -c $path_to_core $path_to_executable
> >
> > Then type:
> >
> >    bt
> >
> > This will print a back trace, and that will tell you which subroutine
> > the the program was in when it died.   Even if you don't know enough
> > to do something with this information, its a great thing to paste into
> > a bug report or email to the maintainer (I always start with the
> > distro I'm using and start going upstream from there).
> > If you do know what to make of a back trace, you can usually (though
> > not always) figure out exactly what the problem is, and fix it.
> >
> > That said not all core dumps are actually bugs in the program.  Many
> > times programs will core dump, like the kernel panics when certain
> > things are expected to be a certain way and they are not (this is
> > called an assert).   The thinking is that to do anything else except
> > drop core could cause serious problems.  Some of these asserts catch
> > bugs, but others catch problems in the OS, libraries, your sysem setup
> > or your hardware (in some cases it could be your just out of memory,
> > and it happened that that last malloc was real critical).
> >
> > All that said most core dumps are due to lazy or tired programmers not
> > validating their data properly (well, and no matter how rigorous you
> > are in you approach to coding sometimes the neorons simply misfire).
> >
> > Chers...james
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>
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-- 
Robert Dale