bpf -> kernel panic

[Andrea Venturoli]

** Reply to note from Giorgos Keramidas <keramida at ceid.upatras.gr> Tue, 18 Mar 2003 21:46:43 +0200


> > > Can you try building yourself a kernel with debugging information 
> > > and get a crash dump from the panic? 
> > 
> > I'll have a try. 
> > What should I do after I have a crash dump? 
>  
> Follow the instructions at 
> http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebug.html 
>  
> Especially the first section: ``Debugging a Kernel Crash Dump with gdb''.

Ok. It's been long time since this thread was put on hold... :)
I've been able to build a debug kernel, install it, run it and happen to experience a crash in umount while shutting
down to single user mode.

Now I have this dump, I tried examining it, but I could not come to any useful conclusion.
Before I produce a crash on purpose launching e.g. tcpdump, I'd like to understand the whole thing a little better,
practising on this dump I have. (btw it's not the first time the machine dump on umount either).

I'm a long time C/C++/Assembler programmer and I'm quite accustomed to basic gdb use, but of course that doesn't mean
I'm able to understand at a glance code others have written, and I'm no FreeBSD kernel guru.

So, I do I go about it? Is there anyone or any doc that can help me? Some sort of tutorial? Does anyone thinks
he can get some useful information with a quick look at the whole stack backtrace?

One things that puzzles me is that, in a few frames, the functions name is replaced with ???.

If this is not the right place to ask, which is?

Altough this is by no mean an urgent matter, I'd like to deal with it completely sooner or later

 bye & Thanks a lot
        av.