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-   -   "Kernel panic: VFS: Unable to mount root fs" - Kernel fails to boot linux (http://www.linuxquestions.org/questions/linux-general-1/kernel-panic-vfs-unable-to-mount-root-fs-kernel-fails-to-boot-linux-477447/)

Freedom Seeker 08-25-2006 10:07 PM

"Kernel panic: VFS: Unable to mount root fs" - Kernel fails to boot linux
 
My kernel panics when I boot my linux. Error message:
Code:

VFS: Cannot open root device "802" or 08:02
Please append a correct "root=" boot option
Kernel panic: VFS: Unable to mount root fs on 08:02

I installed Slackware 10.2 on my Maxtor 40GB USB harddrive using the adaptec.s kernel. After a flawless installation to /dev/sda2, I used my BIOS's "boot from USB Flash Drive," and LILO successfully started the default adaptec.s linux kernel. After 11 pages of boot messages, the kernel panic message appeared.
I have tried to boot using LILO (installed to sda's MBR), the slackware CDs and floppy boot disk. I partitioned /dev/sda1 as swap, and /dev/sda2 as RFS (my root folder). Is there a file I need to modify or kernel I need to patch so I can boot linux from my hardrive? Any help is very much appreciated.

Extra boot lines of interest: (what does 802 mean?)
Code:

Kernel command line: BOOT_IMAGE=Slackware ro root=802
VFS: Disk quotas vdquot_6.5.1
Journaled Block Device driver loaded
SCSI subsystem driver revision: 1.00


dfego 08-25-2006 10:32 PM

I'm not familiar with the specifics of LILO, since I generally stick with GRUB, and didn't get very far with my Slackware installation, but you should have a file called /etc/lilo.conf.

You might want to take a look here for some details on that file. I know it's from the Gentoo manual, but that part is specifically about setting up LILO, and it might prove to be useful.

Freedom Seeker 08-25-2006 10:48 PM

LILO not the problem, Still Unsolved
 
Dfego: LILO is not the problem, because I receive the same error when I boot using a Slackware boot prompt, which does not use LILO. I have successfully installed LILO and Slackware 10.2 before, but on an internal IDE drive. I suspect the problem I have is occurs in my kernel or it's related files. Thankyou for your suggestion.

dfego 08-25-2006 10:56 PM

Sorry for that, I've had all sorts of boot problems, and now I remember what caused one similar to this. I didn't have the proper things enabled in my kernel, in terms of support for the proper disk drives. All of that has to be compiled in, not as modules. I won't pretend like I know exactly how to do this with Slackware, so I'll hope that is of use to you.

debiant 08-25-2006 11:00 PM

Have you tried doing a search on boot usb harddrive on google, it brought up lots of hits with howtos

Freedom Seeker 08-26-2006 09:58 PM

How do I Install Kernel to /mnt/sda2/ ?
 
Because, my kernel could not mount the filesystem on my USB Harddrive (not flash-drive), I used Knoppix to download the latest kernel: linux-2.6.17, and customize it. I made sure to include support for SCSI disks, SCSI emulation, mass USB storage, and RFS filesystem support. I suspect that by default Slackware implemented the needed SCSI support as a module, therefore the Kernel couldn't mount the filesystem. After I customized the kernel, I made a copy of .custom, and compiled the linux-2.6.17 kernel into an RPM, which I assume includes all the necessary initrd, config and modules.

My difficulty is this: Because I cannot boot my Slackware system, I must replace the kernel from a bootable OS (Knoppix or MEPIS), but I saw no option to tell the kernel to install under /mnt/sda2/ instead of the root folder on the ramdisk. Currently I have the kernel source (linux-2.6.17.tar.bz2), the compiled custom kernel as an RPM (kernel-2.6.17test1-1.i386.rpm), and the .config file. I tried to run the RPM installer using Knoppix, but I saw no method to redirect the installation path to /mnt/sda2, nor could I type the correct root password for Knoppix, despite resetting the password via the Knoppix menu. (I did not experience any password difficulties using MEPIS.)
How should I go about installing my Kernel to my USB root partition, addressed as /mnt/sda2 from a bootable OS? I don't see an easy way to change the install directory.

Many thanks to all who have and will help me.

btmiller 08-26-2006 11:10 PM

Try chrooting into /mnt/sda2 with chroot /mnt/sda2. This will make /mnt/sda2 your root directory and allow you to use the tools within the Slackware environment ot build and install the new kernel. Type exit to exit the chroot.

Freedom Seeker 08-27-2006 01:37 PM

Chroot is mixed blessing. - unable to "make menuconfig"
 
Btmiller, thankyou for your suggestion. It worked purely for the purpose of swapping the BASH on my slackware installation. Unfortunately, when I tried the make menuconfig prompt in the slackware bash - it replied "bash: make: command not found." So do I need to reinstall slackware to include the programming collection of files, is there a way to install the RPM file of the precompiled kernel from the terminal prompt (that would save some hastle) or do I need to do something else? Please forgive my limited knowledge of linux commands, and thankyou very much for your help.

btmiller 08-27-2006 02:13 PM

Get the make tgz off of the Slackware CD and install it with installpkg. You'll also need the compilers (gcc and binutils I think will do). Remember, Slackware uses tgz packages, not RPMs. If you can find a kernel tgz that will work for you then you can try installing it.

Freedom Seeker 08-27-2006 02:32 PM

Software differences
 
Thankyou btmiller. Because I need the compilers, I will reinstall Slackware with the necessary packages. Then I will reattempt to install the kernel using make menuconfig after using chroot

Quote:

btmiller: Slackware uses tgz packages, not RPMs.
I've noticed that there are multiple software environments under Linux, such as KDE vs GNOME, Debian vs ?, etc. Could someone explain basic differences in those softwares?

Thankyou all for your help.

Freedom Seeker 08-28-2006 07:05 PM

After many attempts to use chroot and su -l (the only way I could finalize the transfer to the Slackware shell), I still recieved many new system errors:

1) what does /bin/sh: /dev/null: Permission Denied mean? I tried chown -R root:root /bin/sh and chown -R root:root /dev/null, but I could not stop the message from appearing.

2) when I ran make modules_install, the message "intstall module-init-tools - see http://www.codemonkey.org.uk/docs/post-halloween-2.6.txt" appeared. Is this needed.

3) I could not compile bzimage to the arch/i386 folder. Any suggestions?

Much thanks to all who have helped me and will help.

the_artful_dodger 11-12-2006 07:48 PM

Perhaps try compiling SCSI support into your kernel (I've had success when NOT as a module).
ex: run make menuconfig and:
Look in Device drivers area under "SCSI". Set "Generic SCSI support" on, and then go to the IDE/ATAPI area and set "Enable SCSI support".
GOod luck.


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