Could it be the newer kernel that is keeping me on the ground?

abstracity · 2007-08-13 11:16:36

Hello everyone. A few days ago I took the time to compile the kernel from source using the stock ARCH config file extracted from /proc/config.gz, modifying it to suit my needs, and then gathering everything up and installing with Pacman. And as some of you have probably guessed from the title, I ended up with a system that wouldn't fire. I had saved the original vmlinuz* Kconfig* and System-map*, so I was still able to boot back into my previous setup in order to try and sort out all the kinks. My first inclination was to think that it had something to do soley with the kernel options that I had manually configured; I had either not enabled a specific kernel option needed to boot my system or had enabled a neccessary component but had selected it as a module instead of a built-in option or vice versa.

So after toying with various options and sitting through a 150 reboots I decided to use the original kernel .config file from the stock "Don't Panic" kernel, because I thought if I was able to boot and run from the kernel configured with that same stock .config file, then surely it would work if I used this same config file when installing the downloaded 2.6.22.2 kernel from kernel.org. Well, after crossing my fingers and pacing back and forth for a good 17.3 minutes outside, I was still left with an unbootable system.

Sorry if that all sounded a little trivial, but I thought it may make good debugging information. So, since even after I configured the kernel with the same .config file used for the ARCH stock kernel and without changing any options whatsoever, then do you think it could be I just needed to use a different kernel version from kernel.org? I read here that it "is generally unsafe" to use an old configuration file for a newer kernel; I had used the extracted .config file from the stock "Don't Panic" kernel with the 2.6.22.2 version kernel taken from kernel.org. Do you think the version of the kernel I used could have been the problem? Do you think I should have used a kernel version other than 2.6.22.2? Thank you.

FUBAR · 2007-08-13 11:28:53

What error are you getting? Maybe you simply passed the wrong "root=" kernel option.

abstracity · 2007-08-13 11:47:15

I am getting an error message similar to others I have seen elsewhere on the web:

:: Loading Initramfs
:: Running Hook [udev]
:: Loading udev...Switched to high resolution mode on CPU 0
done.
:: Running Hook [lvm2]
Scanning logical volumes...
   Reading all physical volumes.  This may take a while...
   No volume groups found
Activating logical volumes...
   No volume groups found
:: Running Hook [filesystems]
:: Loading root filesystems module...
Attempting to create root device '/dev/mapper/system-root'
ERROR: Failed to parse block device name for '/dev/mapper/system-root'
unknown
ERROR: root fs cannot be detected.  Try using the rootfstype= kernel parameter.
Waiting for devices to settle...done.

# (0) Arch Linux
title  Arch Linux Streamlined
root   (hd0,0)
kernel /vmlinuz26-my root=/dev/mapper/system-root ro vga=795
initrd /kernel26.img

# (0) Arch Linux
title  Arch Linux
root   (hd0,0)
kernel /vmlinuz26 root=/dev/mapper/system-root ro vga=795
initrd /kernel26.img

# (1) Arch Linux
title  Arch Linux Fallback
root   (hd0,0)
kernel /vmlinuz26 root=/dev/mapper/system-root ro
initrd /kernel26-fallback.img

I start to wonder from looking at the error message whether or not it does have something to do with me not building in the right options into the kernel, but I had set up the kernel with the same .config that the kernel I can boot into has and I am still unable to fire. I am able to boot into the ARCH stock kernel so I don't think it has anything to do with the config files in /etc, even though I've tried messing with those quite a bit. I wonder what it could be. My apologies if it is a simple PEBKAC issue.

mucknert · 2007-08-13 12:53:57

Why are you recompiling the kernel when you are using the Arch-Config anyway? It's not that you will experience a sudden performance-boost anyway.

abstracity · 2007-08-13 13:04:23

mucknert,

I am recompiling the kernel mostly for learning purposes. I've compiled in the past, but each time I try to get something new out of it and hopefully increase my knowledge and understanding.

kishd · 2007-08-13 13:37:06

What method are you using to re-compile the kernel. There is a nice tutorial in the wiki:

http://wiki.archlinux.org/index.php/Ker … n_with_ABS

Pay particular attention to how to edit the PKGBUILD to insert the 'make menuconfig/xconfig'. This will allow you to modify the stock kernel .config and test different options while still using all of the patches that arch uses.

mucknert · 2007-08-13 14:35:17

Sure, it could count as an "exercise" to compile a kernel but there are more important things to learn about Unix-compatible Operating Systems. If you want to understand how a GNU/Linux-System works: use it, read manpages and so on. If you want to understand how the Linux-Kernel works: read the Source plus comments, read the Makefiles and read the Mailing-List, hack own stuff. Watching something compile hardly helps you to learn anything at all.

No offense intended but I find compiling your own kernel to be a useless exercise unless you need something specific (patch, driver and so on) in there.

EDIT: Wiped the On-Topic-Stuff. It was no good.

Last edited by mucknert (2007-08-13 15:05:37)

FUBAR · 2007-08-13 15:00:19

Seems like you forgot to include support for the filesystem on your / (/dev/mapper/system-root, which is the exact same name as my root device! ).

[edit]
Boot off a live CD and try to mount your / manually. Maybe something bad happened that wiped out your /.
[/edit]

Last edited by FUBAR (2007-08-13 15:01:02)

abstracity · 2007-08-13 22:28:38

kishd,

I was currently using this simple wiki tutorial for compiling from source, but I will try the ABS approach and see what happens.

mucknert,

I do some of the things you've mentioned, but I guess it never occured to me that the task of compiling the kernel didn't really fit into the grand scheme of conceptual linux knowledge. Thanks for the advice and bringing your philosophy to the forefront. I will use it as best as I can.

FUBAR,

I am still able to boot from the old kernel that is using the same partition as its / mount point, and I've enabled all the options in the kernel menu for filesystems, even ones I had no interest in ever using--just to be on the safe side. I did manage to boot from a live cd followed by a boot from my old kernel and both procedures seemed to turn out fine. I am going to try to compile with ABS and see if that allows me to boot from my customized kernel configuration.

Thanks for all the advice!

Magician21 · 2007-08-14 11:49:30

When I first started using Arch as the basis for a Myth box, I recompiled kernels a lot (~2 years ago). I came from Slackware, so it was something I expected to do. I got away from that once I got the hang of using Arch, because a simple kernel upgrade via pacman gave me the drivers I needed.

One thing I noticed from your post...

# (0) Arch Linux
title Arch Linux Streamlined
root (hd0,0)
kernel /vmlinuz26-my root=/dev/mapper/system-root ro vga=795
initrd /kernel26.img

# (0) Arch Linux
title Arch Linux
root (hd0,0)
kernel /vmlinuz26 root=/dev/mapper/system-root ro vga=795
initrd /kernel26.img

You're using the same initrd for both your streamlined and normal boots. Did you build a new one with mkinitcpio? If you're removing stuff (assumption: streamline == remove), the driver for your root fs may not be in the kernel any longer, and would need to be in the initrd.

Hope this helps, or at least does no harm

Arch Linux

#1 2007-08-13 11:16:36

Could it be the newer kernel that is keeping me on the ground?

#2 2007-08-13 11:28:53

Re: Could it be the newer kernel that is keeping me on the ground?

#3 2007-08-13 11:47:15

Re: Could it be the newer kernel that is keeping me on the ground?

#4 2007-08-13 12:53:57

Re: Could it be the newer kernel that is keeping me on the ground?

#5 2007-08-13 13:04:23

Re: Could it be the newer kernel that is keeping me on the ground?

#6 2007-08-13 13:37:06

Re: Could it be the newer kernel that is keeping me on the ground?

#7 2007-08-13 14:35:17

Re: Could it be the newer kernel that is keeping me on the ground?

#8 2007-08-13 15:00:19

Re: Could it be the newer kernel that is keeping me on the ground?

#9 2007-08-13 22:28:38

Re: Could it be the newer kernel that is keeping me on the ground?

#10 2007-08-14 11:49:30

Re: Could it be the newer kernel that is keeping me on the ground?

Board footer