Installing new Debian kernel - what are steps to do?

tr · 09-10-2005, 05:33 PM

Hi all,

I can install new kernel and modules OK but what has to be changed in minirt.gz?

This is what I have done:
I have started my machine from a remastered CD where I have knoppix-remaster script installed. So I can choose chroot and start things to do with Apt.

I have installed e.g. following packages:

Code:

apt-get install linux-image-2.6.12-1-686 unionfs-source cloop-src loop-aes-module

Then I have installed kernel-image, I have extracted module packages:

Code:

tar jxvf unionfs.tar.bz2
tar jxvf cloop.tar.bz2

Those packages were extracted to /usr/src/modules.

Then I compiled and installed cloop module (cloop.ko) for that new kernel from /usr/src/modules/cloop/debian ():

Code:

m-a a-i cloop

That 'm-a' means 'module-assistant' and 'a-i' means 'auto-install'. I think that my donwloading cloop.ta.bz2 beforehand was unnecessary - module-assistant and auto-install does also downloading automatically.

Then I compiled unionfs module (unionfs.ko) from /usr/src/linux:

Code:

make-kpkg --added-modules=unionfs-module modules_image

Is that unionfs from Apt repository too old for 2.6.12 kernel?

I have also installed linux-headers-2.6.12-1-686 and linux-source-2.6.12(-6) to be sure that everything needed is installed, and some other packages which are carried with Knoppix CD - ipw2100-modules, ipw2200-modules, ndiswrapper-driver (compiled also them). Perhaps I have forgot something but this far everything seems to be right

But what to do next? Copy new kernel vmlinuz-2.6.12-1-686 to /boot/isolinux and replace linux with it? Have tried it but is didn't help. I have new modules cloop.ko and unionfs.ko but what are those scripts (cloop.o and unionfs.o) in minirt.gz file? Should I modify them also?

-tapsa-

**mcreel** · 09-12-2005, 08:32 AM

Hey, thanks for this message, I think you answered a question of mine. I believe that you need to gunzip minirt.gz and place your newly compiled cloop.o into the /modules directory, then recompress minirt. Then I think you're done.

tr · 09-12-2005, 09:12 AM

Originally Posted by mcreel

I believe that you need to gunzip minirt.gz and place your newly compiled cloop.o into the /modules directory, then recompress minirt. Then I think you're done.

Thank for your answer but cloop.o is a script and cloop.ko is a module. In minirt.gz is a symlink to /lib were modules are located and therefore there' s no need to copy cloop.ko in minirt. But something this must have to do with cloop.o or cloop-utils.

-tapsa-

**mcreel** · 09-13-2005, 08:45 AM

Hi,
If you do the steps
gunzip minirt.gz
mount -o loop minirt /mnt
cd /mnt/modules
less cloop.o

you will see that cloop.o is not a script. If you replace this cloop.o with the one that you obtain after compiling cloop using your new kernel, re-gzip minirt, and replace minirt.gz with the new one, then I think that your new kernel will boot.

tr · 09-13-2005, 04:11 PM

Originally Posted by mcreel

If you replace this cloop.o with the one that you obtain after compiling cloop using your new kernel, re-gzip minirt, and replace minirt.gz with the new one, then I think that your new kernel will boot.

This is what I don't undestand. I have no cloop.o file after compiling - only cloop.ko module file. I must have missed something really badly.

And an other thing: in minirt's /static directonary I have ash, insmode, modprobe and symlinks init and sh pointing to ash.
I have also symlink to /sbin pointing to ash, insmode and modrobe. Should I replace those /static files with there files from my system?

-tapsa-

**shah** · 09-13-2005, 04:28 PM

You will never get any *.o when compile kernel but only *.ko.
Copy all the needed modules to miniroot /modules and rename all with *.o.
That's how I did it...not in knoppix, but on kanotix.

tr · 09-16-2005, 08:01 PM

Originally Posted by shah

You will never get any *.o when compile kernel but only *.ko.
Copy all the needed modules to miniroot /modules and rename all with *.o.
That's how I did it...not in knoppix, but on kanotix.

No, it can't be done. If I look unionfs.ko with Midnight Commander (mc) it don't even look similar to unionfs.o. And it's much bigger:
/lib/modules/2.6.12/kernel/fs/unionfs.ko size: 6083229
(from Knoppix 3.8.1 minirt.gz unionfs.o size: 1298136)

Cloop.ko is little bit smaller than cloop.o but it has nothing to do with cloop.ko (don't look similar):
/lib/modules/2.6.12/extra/cloop.ko size: 15745
(from mnirt.gz cloop.o size: 21563)

I have even tried to install an other kernel 2.6.12-1-386, and kernel modules differently by:

Code:

make-kpkg modules_install

No help.

-tapsa-

**firnsy** · 09-17-2005, 08:54 AM

Ok firstly *.o modules, if I remember, are a legacy of kernel modules prior to the 2.6.x series, to which they were change to *.ko. As knoppix used to be 2.4.x based, then later dual 2.4.x/2.6.x, and now 2.6.x only. It is understandable that there may be a few legacies lying around particularly with the miniroot.gz file as it does not require the amount of upkeep that the cloop image requires.

With that said. The cloop.ko and unionfs.ko files are the ones you are after, the .ko are just indicative that the were compiled with at least a 2.6.x kernel. You can incorporate them in one of two ways as mentioned you can rename cloop.ko (uniofs.ko) to cloop.o (unionfs.o) or you can modify linuxrc to load the .ko extension instead of the .o extension.

The reason unionfs is so large is that it still under very heavy development and as such by default it configured to compile with a lot of debugging information (and I mean a lot), you can either remove the debug flags from the unionfs Makefile or simpler use the strip command to remove uneeded portions of that module (eg strip --strip-uneeded unionfs.ko), if I remember that will drop it to around 2MB instead of the default 6MB.

tr · 09-17-2005, 02:19 PM

Originally Posted by firnsy

The reason unionfs is so large is that it still under very heavy development and as such by default it configured to compile with a lot of debugging information (and I mean a lot), you can either remove the debug flags from the unionfs Makefile or simpler use the strip command to remove uneeded portions of that module (eg strip --strip-uneeded unionfs.ko), if I remember that will drop it to around 2MB instead of the default 6MB.

Thanks! That was very important thing to know! I have used Debian for years but never even knew of strip command!

The size of stripped unionfs.ko is about 1.8 MB. But still there's not room enough for that. So I removed some scsi modules and enabled noscsi="yes" from linuxrt.

Now the problem is when booting (from Qemu):

Code:

Looking for CD-ROM in: /dev/hdxX
cd: can't cd to /modules/scsi

If they really are needed so should I replace those with new modules (*.ko)? But there's about 2.5 MB of them - much more than original *.o files. What scsi modules are really needed? If I'm right those are needed only with scsi CD-ROM drives - not with ide CD-CDROM drives. And why all modules have permissions 755?

I think that minirt.gz file should be updated totally in original Knoppix CD (DVD). So it would be little easier to catch what should be done if somebofy tries remastering with new kernel. And what kernel should be used? Debian kernel with Debian patches: 'apt-get install linux-image-_something' or vanilla kernel downloaded from kernel.org and compiled with original Knoppix .config file from /boot directory?

What else should be compiled than kernel: unionfs, cloop, loop-aes, some extra modules? What are not included in Debian kernel package?

-tapsa-

**firnsy** · 09-19-2005, 02:54 AM

The size of stripped unionfs.ko is about 1.8 MB
Have you tried removing the debugging information and then stripped. I haven't but it may be worth a try.
You know that you can rebuild the miniroot.gz file from scratch and increase the size of it (4MB is the default i believe) so there is no reason you couldn't build an 8MB version and lift the size restrictions.

I have moved from the standard initrd format to the newer initramfs (cpio archive) and build my miniroot dynamically with each rebuild, so there is no labouress loopback mounting involved.