cvs commit: src/sys/conf kern.post.mk

[Garance A Drosihn]

At 8:58 PM +1000 9/11/05, Peter Jeremy wrote:
>
>A number of people have mentioned losing the debug kernel when
>they do a rebuild.

I can't speak for others, but I mentioned losing the debug-symbol
information before the point in time where I actually needed it
(due to some sytsem panic).  I did not mention building a new
kernel.  I have removed files from /usr/obj/usr/src without
building any new kernel, so the problem does not require a rebuild.

>The normal reasons for doing a rebuild are either that you have
>updated your source or you've changed your config.

The "normal" reasons are not universally true.  Ie, even if the
"normal" reasons apply 85% of the time, there's 15% of the time
when they don't apply.  And the coredumps lost in that 15% are
still likely to be valuable.  Valuable and lost.

>In the latter case, I would suggest that the only reason to change
>the kernel config is if you are planning on installing a new kernel,
>so again you don't need the old debug kernel.

Except when you built the new kernel, and it panics IMMEDIATELY
upon boot, so you revert back to the previous kernel.  And that
previous kernel is one which "only occasionally" panics.

Now, I know that the above comments do not apply 100% of the time,
but they apply often enough that I've been burned (multiple times!)
where I did not have the debug symbols for a coredump generated
from an unexpected system panic.  And I know other freebsd users
who have burnt by this same issue.

So I'd like to see some change done.  Maybe not this one, but this
one will do nicely until a better one comes along.

>In this change intended for -current only or will it remain in
>7-RELEASE?

I expect it's much too soon to decide that.  Let's get 6.0-release
finished before we worry about the low-level details of exactly
how 7.0-release should be built!   :-)

-- 
Garance Alistair Drosehn            =   gad at gilead.netel.rpi.edu
Senior Systems Programmer           or  gad at freebsd.org
Rensselaer Polytechnic Institute    or  drosih at rpi.edu