On 5 Jul 2006, at 23:07, Christos Zoulas wrote:

> In article <44AC3080.15957.784ADE@localhost>,
> David Lord <david@lordynet.org> wrote:
> >
> >I have four pcs running NetBSD 3.0. On reboot I'm regularly seeing a
> >kernel panic from three of them, either during bootup of within a few
> > minutes later. The pc that doesn't seem to show the problem is a p4-
> >2000, whilst slowest an amd586-133 is most likely to give the panic,
> >maybe 1 in 3 reboots. The k6-400 has managed uptime of 41 days and
> >then had to be rebooted a couple of times to use a new kernel. I've
> >seen the problem with GENERIC kernel but needed some extra options
> >and took the oportunity to remove others that weren't relevant.
> >
> >Error is same:
> >kernel: page fault trap, code=0
> >Stopped at: netbsd:fr_derefrule+0x1c7: cmpl $0x2,0x88(%edx)
> >
> >Any ideas as to how to track this down?
> 
> You can compile the offending file adding -S -gstabs to the compile
> line to produce an assembly file. Then you can objdump --disassemble
> the kernel and locate the offending code. Finally locating the line by
> matching the assembly instructions in the .s file should give you the
> c code line number from the stabs. From there, you can look at the c
> code and possibly add some debugging to help you track the problem
> down.

OK, thanks for that. First I didn't even know what the format of the 
error message was other than to me it appeared to refer to a routine 
and possibly give the instruction that caused the problem.

I've just run grep on the kernel source and only found fr_derefrule 
to be present in several files in /usr/src/sys/dist/ipf.

It will be next week before I get time to compile to get the assembly 
code. I've also downloaded more recent ipf and will compare with 
that.

Thanks

David