Stupid kernel build question

[Steffen Grunewald]

Hi,

I'd like to customize my own kernel for the FAI-installed nodes.
So basically I got the kernel sources, the necessary patches, and a
.config file of a previous version to get a head start.
Unfortunately I get stuck when rebooting. Here's the snippet from my
work log: (I will publish the full one as soon as I got through)

...
OK; so I now also want to use my own kernel, since i2c and lm-sensors
that come with Debian kernels are quite outdated. 
I didn't succeed to compile the 2.4.26 kernel with the patches, so I 
decided to use a pristine 2.4.27 instead and make my own kernel:
	cd /usr/src
	# get kernel
	wget -r -l1 -nd www.kernel.org/pub/linux/kernel/v2.4/linux-2.4.27.tar.bz2
	# unpack kernel
	tar jxf linux-2.4.27.tar.bz2
	# rename to debian standard
	mv linux-2.4.27 kernel-source-2.4.27
	# get patches (for 2.4.26, doesn't matter)
	apt-get install kernel-patch-2.4-i2c kernel-patch-2.4-lm-sensors
	# unpack for patch
	gunzip kernel-patches/diffs/*/kernel-2.4.26-*.patch.gz	
	# get config file for subarchitecture (mine is k7-smp, Athlon MP)
	apt-get source kernel-image-2.4-k7-smp
	cp -p kernel-image-2.4.26-i386-*/config/k7-smp kernel-source-2.4.27
	# patch kernel
	cd kernel-source-2.4.27
	patch -p1 <../kernel-patches/diffs/i2c/kernel-2.4.26-*
	patch -p1 <../kernel-patches/diffs/lm-sensors/kernel-2.4.26-*
	# fill in new config file entries (answer "M" where possible, "Y" else)
	cp -p sm
	make oldconfig
	vi .config
		CONFIG_CRAMFS=n			# cramfs isn't needed
		CONFIG_ROMFS_FS=y		# romfs support in kernel
		CONFIG_BLK_DEV_RAM_SIZE=10240	# 8192 is too small
	# set own identity
	vi /etc/kernel-pkg.conf
	# set different initrd fs
	vi /etc/mkinitrd/mkinitrd.conf
		MKIMAGE="genromfs -s %s -f %s"
	apt-get install genromfs	# really necessary here?
	make-kpkg \
		--revision 20040818 \
		--subarch k7-smp \
		--initrd --bzimage \
		binary modules
	cd ..
	mv kernel-*.deb $FAI_CONFIGDIR/files/packages
	cd $FAI_CONFIGDIR/files
	./mkPkg				# create packages/Packages.gz
	cd ../scripts/DEFAULT
	cat <<EOF >S00
		# prerequisites for S01 kernel install
		fcopy /etc/mkinitrd/mkinitrd.conf
		apt-get genromfs
		exit 0
	EOF
	chmod +x S00
	mkdir -p $FAI_CONFIGDIR/files/etc/mkinitrd/mkinitrd.conf
	cp -p /etc/mkinitrd/mkinitrd.conf \
		$FAI_CONFIGDIR/files/etc/mkinitrd/mkinitrd.conf/DEFAULT
If you now restart your installation, you might even succeed when rebooting...
For me, it does not, I get 
	VFS: Mounted root (romfs filesystem) readonly.
	...
	.../ide-core.o: insmod ide-detect failed
	.../ide-core.o: insmod ide-disk failed
	Journalled Block Device driver loaded
	pivot_root: No such file or directory
	/sbin/init: ... cannot open dev/console: No such file
	Kernel panic: Attempted to kill init!

Note that I had to switch to romfs instead of cramfs since I could not
find the "lost Debian cramfs initrd patch".

I did some modifications in mkinitrd.conf:
	MODULES=all -> 32MB initrd, too big.
	MODULES=dep -> find out exactly what's needed :-( not FAIable
	MODULES=most.
	ROOT=probe -> fails
	ROOT=/dev/hda1 -> fails too. 



(If I use the prebuilt kernel from Debian Sarge, everything is fine.)
(I will go on and save the initrd's to compare their contents...)


Any suggestions how to get the thing working is welcome. I'd love to
have a listing of loaded modules... should I simply go and
lsmod >/etc/mkinitrd/modules (OK with minor editing) so I could use
MODULES=dep?


Steffen

-- 
Steffen Grunewald * * * Merlin cluster admin (http://pandora.aei.mpg.de)
Albert-Einstein-Institut (MPI Gravitationsphysik, http://www.aei.mpg.de)
       Science Park Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
e-mail: steffen.grunewald(*)aei.mpg.de * +49-331-567-{fon:7233,fax:7298}