[gentoo-dev] Why is preempt-kernel *required* for building a kernel using gentoo-sources ?

[gentoo-dev] Why is preempt-kernel *required* for building a kernel using gentoo-sources ?

[Dan Naumov]

Hey.

I just stubled across a very weird problem. I was told that using preempt slows down SETI so I decided to do some benchmarking to see whether it's true. I loaded my kernel config, disabled preempt and ran  "make dep clean bzImage modules modules_install", the build failed with:

fs/fs.o: In function `dput':
fs/fs.o(.text+0x11ff5): undefined reference to `atomic_dec_and_lock'
make: *** [vmlinux] Error 1

I go back to menuconfig, add preempt kernel back, save config, recompile again and it works...how come ? Changing the compile optimisations doesn not seem to have any effect on this... According to a thread on Gentoo Forums (http://forums.gentoo.org/viewtopic.php?t=3915), I am not the only have having the problem either.

Sincerely,
Dan Naumov

Re: [gentoo-dev] Why is preempt-kernel *required* for building a kernel using gentoo-sources ?

[Kim Nielsen]

On Sun, 2002-06-02 at 17:09, Dan Naumov wrote:
> I just stubled across a very weird problem. I was told that using preempt slows down SETI so I decided to do some benchmarking to see whether it's true. I loaded my kernel config, disabled preempt and ran  "make dep clean bzImage modules modules_install", the build failed with:
> 
> fs/fs.o: In function `dput':
> fs/fs.o(.text+0x11ff5): undefined reference to `atomic_dec_and_lock'
> make: *** [vmlinux] Error 1
> 

try coping the .config file somewhere else and do a make mrproper ..
then copy the .config file back and recompile your kernel .. it worked
for me

/Kim
-- 
I'm the face that stares at you from the shadows.
                        http://www.insecurity.dk

Re: [gentoo-dev] Why is preempt-kernel *required* for building a kernel using gentoo-sources ?

[Matthew Kennedy]

Kim Nielsen <kn@insecurity.dk> writes:

> try coping the .config file somewhere else and do a make mrproper ..
> then copy the .config file back and recompile your kernel .. it worked
> for me

I'd just like to add to what Kim said: "make mrproper" is a *really*
good idea before *any* kernel recompile. See the Linux docs in
/usr/src/linux about this.

-- 
Matthew Kennedy
Gentoo Linux Developer
Bugs go in http://bugs.gentoo.org!