Hi,

I'm currently fiddling with the packaged 2.6.10 kernel, and I have a few
questions about that.

1) I use mainly ReiserFS, except for my /boot partition which is ext2. Can I
safely omit the initrd if I compile ReiserFS directly into the kernel, or
is there something else I'd need?

2) What exactly does System.map do?

3) I have several kernels in /boot, and several according System.map files.
Question: when my /boot/grub/menu.lst stanza says
"kernel=/vmlinuz-ide-2.4.29", does this mean that automatically the
according System.map-ide-2.4.29 will be used (since it bears the same
appendice)? Or do I have to symlink each to vmlinuz resp. System.map?

4) I tried to recompile the stock 2.6.10 kernel, and the only alteration I
made was change the processor type from 486 to 586/6x86. I couldn't boot on
that new kernel, because there was an error about a wrong reiserfs module.
I *think* I should have repeated mkinitrd, but then... AFAIK, I should have
*two* initrd.gz files in /boot... one for the stock 2.6.10 kernel, and
another one for the recompiled one. Hence my question above, about how to
do without an initrd.

Niki Kovacs
--
I'm not as think as you stoned I am.

> 1) I use mainly ReiserFS, except for my /boot partition which is ext2. Can
> I safely omit the initrd if I compile ReiserFS directly into the kernel,
> or is there something else I'd need?

Well, maybe you'll need some IDE drivers. I've always compiled my own
kernels so I don't know exactly how the 2.6.10 package is done. But if you
alread boot-ed with it. See what modules were loaded (whit lsmod), and from
that list you should be able to deduce which drivers should be compiled in
the kernel.

> 2) What exactly does System.map do?

System.map is mostly not used, but sometimes it helps with debuging. Also
klogd may use it when loging stuff (but its not necesseary).

> 3) I have several kernels in /boot, and several according System.map
> files. Question: when my /boot/grub/menu.lst stanza says
> "kernel=/vmlinuz-ide-2.4.29", does this mean that automatically the
> according System.map-ide-2.4.29 will be used (since it bears the same
> appendice)?

Yes, klogd is the only program that automatically tries to use
System.map-xx, and it will try to open System.map-`uname -r`.
The other program that might use System.map is /etc/rc.d/rc.modules... and
it will also try System.map-`uname -r`.

> 4) I tried to recompile the stock 2.6.10 kernel, and the only alteration I
> made was change the processor type from 486 to 586/6x86. I couldn't boot
> on that new kernel, because there was an error about a wrong reiserfs
> module. I *think* I should have repeated mkinitrd, but then...

Offcourse, the modules are intimately tied to the kernel... its usualy not
possible to mix them.

> AFAIK, I should have *two* initrd.gz files in /boot... one for the stock
> 2.6.10 kernel, and another one for the recompiled one. Hence my question
> above, about how to do without an initrd.

I've always favored kernels that can boot without initrd. I guess that may
be a better choice for you too.

--
damjan

Hi Niki,
On Fri, 27 May 2005 11:46:16 +0200, Niki Kovacs <mickey@mouse.com> wrote:
>
>I'm currently fiddling with the packaged 2.6.10 kernel, and I have a few
>questions about that.
>
>1) I use mainly ReiserFS, except for my /boot partition which is ext2. Can I
>safely omit the initrd if I compile ReiserFS directly into the kernel, or
>is there something else I'd need?

You are a worry 2.6.10 is non-stable, go for 2.6.11.10 or later,
compile in reiserfs and ext2 -- I put up an example of this very
recently. You do not want reiserfs4!
>
>2) What exactly does System.map do?

Take a peek at it, it is plaintext. ksymoops uses it (I think) to
work out what crashed where... Not sure if it also used by modules?
>
>3) I have several kernels in /boot, and several according System.map files.
>Question: when my /boot/grub/menu.lst stanza says
>"kernel=/vmlinuz-ide-2.4.29", does this mean that automatically the
>according System.map-ide-2.4.29 will be used (since it bears the same
>appendice)? Or do I have to symlink each to vmlinuz resp. System.map?

Yes, the kernel (bzImage|vmlinuz), System.map and modules are linked
by kernel version:
>
grant@sempro:~$ ls /boot/
README.initrd@ bzImage-2.4.30-hf2 config-2.4.31-rc1a
System.map-2.4.30-hf2 bzImage-2.4.31-rc1 config-2.6.11.10a
System.map-2.4.31-rc1 bzImage-2.4.31-rc1a config-2.6.11.10b
System.map-2.4.31-rc1a bzImage-2.6.11.10a config-2.6.12-rc5-mm1a
System.map-2.6.11.10a bzImage-2.6.11.10b config-2.6.12-rc5a
System.map-2.6.11.10b bzImage-2.6.12-rc5-mm1a diag1.img
System.map-2.6.12-rc5-mm1a bzImage-2.6.12-rc5a map
System.map-2.6.12-rc5a config-2.4.30-hf2
boot.0803 config-2.4.31-rc1

grant@sempro:~$ ls /lib/modules/
2.4.30-hf2/ 2.4.31-rc1a/ 2.6.11.10b/ 2.6.12-rc5a/
2.4.31-rc1/ 2.6.11.10a/ 2.6.12-rc5-mm1a/

root@sempro:/lib/modules# lilo
Warning: COMPACT may conflict with LBA32 on some systems
Added 12-rc5-mm1a
Added 2.6.12-rc5a
Added 2.6.11.10b *
Added 2.6.11.10a
Added 2.4.31-rc1a
Added 2.4.31-rc1
Added 2.4.30-hf2
Added winxp

Do yourself a favour, lose the symlinks, remember to adjust your
bootloader ) I use lilo, can't comment on grub, or, I can't see
any point in changing bootloader, learn one well and stick with it.

>4) I tried to recompile the stock 2.6.10 kernel, and the only alteration I
>made was change the processor type from 486 to 586/6x86. I couldn't boot on
>that new kernel, because there was an error about a wrong reiserfs module.
>I *think* I should have repeated mkinitrd, but then... AFAIK, I should have
>*two* initrd.gz files in /boot... one for the stock 2.6.10 kernel, and
>another one for the recompiled one. Hence my question above, about how to
>do without an initrd.

Refer archives, or see http://scatter.mine.nu/test/linux-2.6/ to pull a
couple working .configs. peetoo is ext2 /boot --> reiserfs over RAID0,
sempro is large primary reiserfs, both run 2.6.11.10 or sometimes 2.4
for testing.

You really are much better off not fiddling with distro kernel, grab the
latest stable kernel and leave distro kernel in as backup.

--Grant.

Fri, 27 May 2005 11:59:50 +0200 - Damjan <gdamjan@gmail.com> :
> > 1) I use mainly ReiserFS, except for my /boot partition which is
> > ext2. Can I safely omit the initrd if I compile ReiserFS directly
> > into the kernel, or is there something else I'd need?
>
> Well, maybe you'll need some IDE drivers. I've always compiled my
> own kernels so I don't know exactly how the 2.6.10 package is done.
> But if you alread boot-ed with it. See what modules were loaded
> (whit lsmod), and from that list you should be able to deduce which
> drivers should be compiled in the kernel.

The default 2.6.x Linux kernel configuration in testing/ already
contains the IDE driver (it is built-in). Note that when switching
from 2.4.x to 2.6.x, swap space should be converted from v0 to v1 with
mkswap : without it, the swap swap won't be mounted at boot time.

> > 2) What exactly does System.map do?
>
> System.map is mostly not used, but sometimes it helps with debuging.
> Also klogd may use it when loging stuff (but its not necesseary).

The System.map file is only used to resolve kernel-space addresses to
symbol names. This operation only happens when there is a general
protection fault is the Linux kernel. For other logging source, it is
quite useless.

> > 3) I have several kernels in /boot, and several according
> > System.map files. Question: when my /boot/grub/menu.lst stanza
> > says "kernel=/vmlinuz-ide-2.4.29", does this mean that
> > automatically the according System.map-ide-2.4.29 will be used
> > (since it bears the same appendice)?
>
> Yes, klogd is the only program that automatically tries to use
> System.map-xx, and it will try to open System.map-`uname -r`. The
> other program that might use System.map is /etc/rc.d/rc.modules...
> and it will also try System.map-`uname -r`.

The Klogd daemon do no try to automatically use System.map-* files. It
only try /boot/System.map (and /System.map, /usr/src/linux/System.map)
which is a symlink to the proper System.map-* file on Linux Slackware.

--
LiNuCe

Grant Coady wrote:

> You are a worry **2.6.10*is*non-stable,*go*for*2.6.11.10*or*later,
> compile in reiserfs and ext2 -- I put up an example of this very
> recently.**You*do*not*want*reiserfs4!

Hi Grant,

I'm just following your advice, grabbed necessary patches up to 2.6.11.10
and your .config, compiled and everything went OK (without initrd)).
Currently doing some fine-tuning.

Must say I like the competent laconism of your posts.

cheers,


Niki Kovacs
--
I'm not as think as you stoned I am.

>> > 3) I have several kernels in /boot, and several according
>> > System.map files. Question: when my /boot/grub/menu.lst stanza
>> > says "kernel=/vmlinuz-ide-2.4.29", does this mean that
>> > automatically the according System.map-ide-2.4.29 will be used
>> > (since it bears the same appendice)?
>>
>> Yes, klogd is the only program that automatically tries to use
>> System.map-xx, and it will try to open System.map-`uname -r`. The
>> other program that might use System.map is /etc/rc.d/rc.modules...
>> and it will also try System.map-`uname -r`.
>
> The Klogd daemon do no try to automatically use System.map-* files. It
> only try /boot/System.map (and /System.map, /usr/src/linux/System.map)
> which is a symlink to the proper System.map-* file on Linux Slackware.

http://kerneltrap.org/node/2588


--
damjan