Hopefully Simple Question on Debugging Kernel Modules

[Scott Long]

David Christensen wrote:
>>>> Just use gdb on bce.ko (built with debug symbols):
>>>>
>>>> gdb /path/to/if_bce.ko
>>>> (gdb) l *bce_intr+0x8df
>>>>
>>>> If you get a crashdump you can run kgdb on it and just walk up to
>> the
>> relevant
>>>> stack frame and use 'l' there to get a listing.
>>>>
>>> One thing that I've never figured out is how debugging symbols are
>>> handled in module builds these days.  If I go to /sys/modules/bce and
>>> do 'make', it generates a .ko and explicitly strips it.  I wind up
>>> having to re-run the link command by hand so I get symbols.  What is
>>> the correct way to do this?  Note that I'm not interested in answers
>>> that involve "go to /usr/src and run make buildkernel" =-)
>> make DEBUG_FLAGS=-g is what I use.  The same thing works for userland
>> tools
>> and the kernel (usually we put 'makeoptions DEBUG_FLAGS=-g' in a kernel
>> config so it is "automatic" for kernels though).
> 
> So is the use of COPTS=-g mentioned in the Developer's Handbook
> (http://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug-kld.html)
> deprecated?  I wasn't able to build with symbols until I used DEBUG_FLAGS='g.
> 

Yes, it appears that the developers handbook is several years out of date.

Scott