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SOLVED! Slackware Dual Boot: Kernel Panic

Dear Forum,

I've just installed Slackware 11.0 on a second partition of my main
SATA drive (/dev/sda7) in the interest of setting up a dual boot with
PCLinuxOS. I'm getting

"Kernel panic -- not syncing -- no init found..."

Here's my MBR lilo.conf:

Code:

# File generated by DrakX/drakboot

# WARNING: do not forget to run lilo after modifying this file



default="linux"

boot=/dev/sda

map=/boot/map

menu-scheme=wb:bw:wb:bw

prompt

nowarn

timeout=100

message=/boot/message

image=/boot/vmlinuz

        label="linux"

        root=/dev/sda1

        initrd=/boot/initrd.img

        append="acpi=ht splash=verbose"

        vga=788

image=/boot/vmlinuz

        label="linux-nonfb"

        root=/dev/sda1

        initrd=/boot/initrd.img

        append="acpi=ht splash=verbose"

image=/boot/vmlinuz

        label="failsafe"

        root=/dev/sda1

        initrd=/boot/initrd.img

        append="failsafe"

image=/boot/vmlinuz

        label="slackware"

        root=/dev/sda7

        initrd=/boot/initrd.img

Here's the lilo.conf from the Slackware install I just did, installed to the root partition of the Slackware install:

Code:

# LILO configuration file

# generated by 'liloconfig'

#

# Start LILO global section

boot = /dev/sda7

#compact        # faster, but won't work on all systems.

prompt

timeout = 300

# VESA framebuffer console @ 1024x768x256

vga = 773

[VESA stuff cut out]

# End LILO global section

# Linux bootable partition config begins

image = /boot/vmlinuz

  root = /dev/sda7

  label = slackware

  read-only # Non-UMSDOS filesystems should be mounted read-only for checking

# Linux bootable partition config ends

How should I actually set this up? Do I need to tag /dev/sda7 as bootable in fdisk?

Thanks, I appreciate any help,
Joel

Linux does not require a partition to be tagged bootable -- only Windows needs that.

I don't know what "File generated by DrakX/drakboot" is -- sounds like something from Mandrake to me.

If your / (root) Slackware partition is /dev/sda7, that part is correct; but the Slackware way of setting up an initial ramdisk image is not "initrd=/boot/initrd.img". From the Slackware instructions:

Code:

mingdao@silas:~$ cat /boot/README.initrd



Slackware initrd mini HOWTO

by Patrick Volkerding, volkerdi@slackware.com

Sat Sep  3 22:20:13 PDT 2005



This document describes how to create and install an initrd, which may be

required to use the 2.6 kernel.  Also see "man mkinitrd".



1.  What is an initrd?

2.  Why to I need an initrd?

3.  How do I build the initrd?

4.  Now that I've built an initrd, how do I use it?





1.  What is an initrd?



Initrd stands for "initial ramdisk".  An initial ramdisk is a very small

Linux filesystem that is loaded into RAM and mounted as the kernel boots,

and before the main root filesystem is mounted.



2.  Why do I need an initrd?



The usual reason to use an initrd is because you need to load kernel

modules before mounting the root partition.  Usually these modules are

required to support the filesystem used by the root partition (ext3,

reiserfs, xfs), or perhaps the controller that the hard drive is attached

to (SCSI, RAID, etc).  Essentially, there are so many different options

available in modern Linux kernels that it isn't practical to try to ship

many different kernels to try to cover everyone's needs.  It's a lot more

flexible to ship a generic kernel and a set of kernel modules for it.  The

generic 2.6 kernel in Slackware supports the ext2 filesystem (which is

used by the initrd), and also supports most IDE controllers (much like the

old bare.i kernel).  So, if you have an IDE based system that uses the

ext2 filesystem, then you will not need to use an initrd to boot.

Otherwise, read on.



3.  How do I build the initrd?



The easiest way to make the initrd is to use the mkinitrd script included

in Slackware's mkinitrd package.  We'll walk through the process of

upgrading to the 2.6.13 Linux kernel using the packages found in

Slackware's testing/packages/linux-2.6.13/ directory.



First, make sure the kernel, kernel modules, and mkinitrd package are

installed (the current version numbers might be a little different, so

this is just an example):



  installpkg kernel-generic-2.6.13-i486-1.tgz

  installpkg kernel-modules-2.6.13-i486-1.tgz

  installpkg mkinitrd-1.0.1-i486-1.tgz



Change into the /boot directory:



  cd /boot



Now you'll want to run "mkinitrd".  I'm using reiserfs for my root

filesystem, and since it's an IDE system the reiserfs module will be

the only one I need to load:



  mkinitrd -c -k 2.6.13 -m reiserfs



This should do two things.  First, it will create a directory

/boot/initrd-tree containing the initrd's filesystem.  Then it will

create an initrd (/boot/initrd.gz) from this tree.  If you wanted to,

you could make some additional changes in /boot/initrd-tree/ and

then run mkinitrd again without options to rebuild the image.  That's

optional, though, and only advanced users will need to think about that.



Here's another example:  Build an initrd image using Linux 2.6.13

kernel modules for a system with an ext3 root partition on /dev/hdb3.

Note that you need both the jbd and ext3 modules to use ext3:



  mkinitrd -c -k 2.6.13 -m jbd:ext3 -f ext3 -r /dev/hdb3





4.  Now that I've built an initrd, how do I use it?



Now that you've got an initrd (/boot/initrd.gz), you'll want to load

it along with the kernel at boot time.  If you use LILO for your boot

loader you'll need to edit /etc/lilo.conf and add a line to load the

initrd.  Here's an example section of lilo.conf showing how this is

done:



# Linux bootable partition config begins

image = /boot/vmlinuz-generic-2.6.13

  initrd = /boot/initrd.gz

  root = /dev/hda6

  label = Lnx2613

  read-only

# Linux bootable partition config ends



The initrd is loaded by the "initrd = /boot/initrd.gz" line.

Just add the line right below the line for the kernel image you use.

Save the file, and then run LILO again ('lilo' at the command line).

You'll need to run lilo every time you edit lilo.conf or rebuild the

initrd.



Other bootloaders such as syslinux also support the use of an initrd.

See the documentation for those programs for details on using an

initrd with them.





---------



Have fun!

You can install LiLO to the MBR and boot both distros. No need to use the root partition. Here is an example of a dual boot /etc/lilo.conf for your viewing pleasure:

Code:

mingdao@silas:~$ cat /etc/lilo.conf

# LILO configuration file

# generated by 'liloconfig'

#

# Start LILO global section

append="panic=15"

boot = /dev/sda

compact        # faster, but won't work on all systems.

prompt

timeout = 50

# VESA framebuffer console @ 1024x768x256

vga = 773

# ramdisk = 0    # paranoia setting

# End LILO global section

# Linux bootable partition config begins

image = /boot/vmlinuz-2.6.18.3

  root = /dev/sda6

  label = Slack-2.6.18.3

  read-only

# Linux bootable partition config ends

# Windows bootable partition config begins

other = /dev/sda1

  label = Windoze

  table = /dev/sda

# Windows bootable partition config ends

If you don't understand, then use <Linux> Google as this is a very old issue.

I think if you setup your initrd image properly, you can boot. But if you installed the default kernel you shouldn't need one. To get back into your Slackware distro boot with Slackware CD1 and at the prompt type:
sata.i root=/dev/sda7 noinitrd ro

Once you're in, fix that initrd and install LiLO to the MBR.

Dear Sir,

Thanks for getting back to me. I am really interested in using Slackware.

I did not install the slackware generate LILO to my MBR because my main system boots fine from the LILO -- are you saying I can add an entry for slackware to that lilo.conf and boot into slackware? Or do I have to install it from slackware and then add PCLinuxOS?

Thanks for the literature on initrd -- I did not set up an initrd.

Do I need to eradicate LILO on the slackware root partition?

I got the kernel panic after not installing LILO to /dev/sda7 initially, however my lilo.conf entries were screwed up then, too. Would this cause the kernel panic?

By the way, I've used google many times to look up this kernel panic and never found a single conclusive answer: if you're aware of an article that addresses it, please post a link to it -- I WOULD REALLY LIKE TO READ IT.

Thanks,
Joel
:newbie:

Hello,

I've since updated my lilo.conf and learned a little about LILO. Here's the file:

Code:

# File generated by DrakX/drakboot

# WARNING: do not forget to run lilo after modifying this file



default="linux"

boot=/dev/sda

map=/boot/map

menu-scheme=wb:bw:wb:bw

prompt

nowarn

timeout=100

message=/boot/message

image=/boot/vmlinuz

        label="PCLinuxOS"

        root=/dev/sda1

        initrd=/boot/initrd.img

        append="acpi=ht splash=verbose"

        vga=788

image=/boot/vmlinuz

        label="PCLinuxOS-nonfb"

        root=/dev/sda1

        initrd=/boot/initrd.img

        append="acpi=ht splash=verbose"

image=/boot/vmlinuz

        label="PCLinuxOS-failsafe"

        root=/dev/sda1

        initrd=/boot/initrd.img

        append="failsafe"

image=/boot/vmlinuz-ide2.4.33.3

        label="slackware"

        root=/dev/sda7

        vga=788

        read-only

Then I run lilo:

Code:



[root@localhost joel]# lilo -v

LILO version 22.6.1, Copyright (C) 1992-1998 Werner Almesberger

Development beyond version 21 Copyright (C) 1999-2004 John Coffman

Released 17-Nov-2004, and compiled at 14:46:41 on Oct 11 2005



Reading boot sector from /dev/sda

Using GRAPHIC secondary loader

Calling map_insert_data

Mapping message file /boot/message -> message-graphic

Calling map_insert_file



Boot image: /boot/vmlinuz -> vmlinuz-2.6.16.27.tex1.lve

Mapping RAM disk /boot/initrd.img -> initrd-2.6.16.27.tex1.lve.img

Added PCLinuxOS



Boot image: /boot/vmlinuz -> vmlinuz-2.6.16.27.tex1.lve

Mapping RAM disk /boot/initrd.img -> initrd-2.6.16.27.tex1.lve.img

Added PCLinuxOS-nonfb



Boot image: /boot/vmlinuz -> vmlinuz-2.6.16.27.tex1.lve

Mapping RAM disk /boot/initrd.img -> initrd-2.6.16.27.tex1.lve.img

Added PCLinuxOS-failsafe



Boot image: /boot/vmlinuz-ide2.4.33.3

Fatal: open /boot/vmlinuz-ide2.4.33.3: No such file or directory

So, I figured out after rebooting with this configuration that it (presumably it=LILO) is loading the wrong kernel image -- I'm getting all the same stuff I would with the PCLinuxOS kernel.

Now the question is, how do I boot the sucker so that it recognizes the kernel image on /dev/sda7? The file is definitely there! What I mean is that when I look at /boot on /dev/sda7, /vmlinuz-ide2.4.33.3 is there; doesn't "root=/dev/sda7" tell LILO where to look?:scratch:

Thanks,
Joel

Question: I notice that you have a line in your lilo.conf that says "panic=15" -- do I need this in my lilo.conf?

To clarify my original reply, I'm already using LILO -- it's already installed on the MBR and I'm configuring everything from within PCLinuxOS. The only systems installed on the computer are PCLinuxOS 0.93 and Slackware 11.0.

Thanks,
Joel

Place a copy of your slackware kernel alongside the PC-linux kernel so that the PG-Linux lilo can find it.

gnashley,

Do you mean in the /boot of my PCLinuxOS install on /dev/sda1?

I found this solution elsewhere on this forum and in others, and I believe it would work. Are there any other solutions? Is this just a matter of setting up LILO, i.e., the lilo command? Is there a lilo option that would convince the lilo command to look in /mnt/sda7/boot/vmlinuz?

Joel

How about a symbolic link in my main /boot folder, for example

vmlinuz2 -> /mnt/sda7/boot/vmlinuz-ide2.4.33.3

Would that put LILO onto the scent?

Joel

You must have the proper names in /etc/lilo.conf.

Code:

mingdao@silas:~$ ls /boot | grep -i 2.4.33.3

System.map-ide-2.4.33.3

config-ide-2.4.33.3

vmlinuz-ide-2.4.33.3

Your error message says there is no /boot/vmlinuz-ide2.4.33.3:

Code:

Boot image: /boot/vmlinuz-ide2.4.33.3

Fatal: open /boot/vmlinuz-ide2.4.33.3: No such file or directory

and your /etc/lilo.conf has:

Code:

image=/boot/vmlinuz-ide2.4.33.3

        label="slackware"

        root=/dev/sda7

        vga=788

        read-only

Perhaps that is because you left a hyphen out of the image name?

When you try to boot Slackware, what happens?

Originally posted by trashbird1240:

Quote:

"Kernel panic -- not syncing -- no init found..."

At that point your system hangs, it will not accept even keyboard input,
so you must depress the Reset switch or turn the power off and reboot.

If you put

Code:

append="panic=15"

in /etc/lilo.conf, when you have a kernel panic your system will reboot
itself after 15 seconds. This gives me enough time to read the terminal
and determine why the kernel panic happened.

Don't symlink your kernel image, just set LiLO up correctly.

Howdy Y'all

Thanks for all the help: I got it to work by copying the slackware kernel to the /boot directory while I run lilo.

That may have in fact been unnecessary since the error was not with the slackware entry, it was that I changed the name of the default entry without changing the name under the default field.

Joel

A classic case of PEBKAC. :D

Ha! What is PEBKAC?

It's been working pretty good -- I'm just trying to configure X and add myself as a user and all that stuff.

It's a really nice system -- very UNIXy. I even logged in to Pine, just for old time's sake!

Joel

PEBKAC

Hang in there -- Slackware has given me back my Personal Computer that Mickey$oft took away. We Slackers in these forums will do whatever we can to help you.

Thankfully I broke the Micro$*ft monopoly long ago in our house with PCLinuxOS. However, Slackware is quickly rising on my favorites list, and I may want to make it my main scientific platform.

I love Slackware so far; I was telling some people last night on IRC that I wish I could use it at work...

If you can get me out of that Broken Window then I'll be a Slacker for life ;)

When I get to grad school I'm setting up my own system, no ifs ands or buts (I think they'll be happy to hear that, actually). If anyone has any experience on this end, let me know.

Joel