Re: Yet another crash in FreeBSD 5.1

Greg 'groggy' Lehey wrote:
> > Please take a look at an older thread named (IIRC) vinum or geom bug?
> > Greg asked for special debug output, but it never happened again for me.
> > A real murphy bug - it happend on three machines once a day and after
> > Gregs response nothing happened over weeks.
> 
> This is the real issue.  Until you supply the information I ask for in
> the man page or at http://www.vinumvm.org/vinum/how-to-debug.html,
> only Terry can help you.

This is BS, Greg.

I deal with about a traceback every other day, and sometimes as
high as 5 in a single day, if it's a busy day for it.

The information I gave him gets him to lines of source code,
instead of just function names with strange hexadecimal numbers
that resolve to instruction offsets that may be specific to his
compile flags, date of checkout of the sources from CVS, etc..

I don't know about you, but I can't easily write assembly
instructions to tape, run them the tape through my teeth, and
read the bits using my dental fillings.


If it's a NULL pointer dereference, the place to find it is by
turning on what debugging there is, and, if that fails, which
it probably will, by eyeballing the lines of source code in
question and understanding the code around it well enough that
you can tell *how* a pointer there could be NULL.  My instructions
*get* him those lines of source.

If you'll notice from his followup posting of the source in
question, Vinum is loaded as a module, and it's the FreeBSD
code that Vinum calls, not Vinum, that's causing the crash.

There's no reason to be paranoid about your baby with me; unlike
some people, personally I like Vinum, so relax and realize that
I'm not trying to blame your code by trying to help him squeeze
more information out of the data he *is* able to gather.

-- Terry