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Linux From Scratch This Forum is for the discussion of LFS.
LFS is a project that provides you with the steps necessary to build your own custom Linux system.

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Old 05-13-2010, 02:49 AM   #1
Lyle
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Can't boot LFS ( kernel panic - not syncing ) LFS 6.6


The following is the output following the panic

Code:
kernel panic - not syncing: Unable to mount root fs on unknown-block(2,0)
Pid:1,comm: swapper
Not tainted 2.6.32.8 #1
panic+0x75/011d
mount_block_root+0x1ce/0x1e5
mount_root+0x6b/0x8b
prepare_namespace+0x170/019d
kernel_init+0xf7/0x19d
? schedule_tail+0x16/0x42
child_rip+ 0xa/0x20
kernel_init+0x6/0x102
child_rip+0x0/0x20
 
Old 05-13-2010, 04:43 AM   #2
business_kid
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kernel panic - not syncing: Unable to mount root fs on unknown-block(2,0)

The middle of that line is your error. You told grub where the root filesystem was, and you were wrong
On the bootup screen hit 'e' (the e key, not e and two '') your boot line comes up. hit 'e' again, and you can edit it. Fix your mistake. press return, and then 'b'

Last edited by business_kid; 05-13-2010 at 04:45 AM.
 
Old 05-13-2010, 07:30 AM   #3
Lyle
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Quote:
Originally Posted by business_kid View Post
kernel panic - not syncing: Unable to mount root fs on unknown-block(2,0)

The middle of that line is your error. You told grub where the root filesystem was, and you were wrong
On the bootup screen hit 'e' (the e key, not e and two '') your boot line comes up. hit 'e' again, and you can edit it. Fix your mistake. press return, and then 'b'
My root filesystem is on /dev/hda1. How can i make grub realize it. What entry do i make.

Last edited by Lyle; 05-13-2010 at 07:32 AM.
 
Old 05-13-2010, 02:31 PM   #4
Lyle
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I tried everything the book said, on cfdisk my partition with LFS is /dev/hda1 so i tried (hd0,1) for grub, didn't work so i tried (hd1,1) and (hd0,0)and /dev/hda /dev/hda0 /dev/hda1. Nothing works.
 
Old 05-13-2010, 02:44 PM   #5
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Hi,

I recently finished the LFS 6.6 book and encountered booting problems too. Although my hard disk also got detected as hda, I was unable to boot into my LFS. After some trying I changed root=/dev/hda1 to root=/dev/sda1 (don't ask me why I did such an illogical thing because I just don't know) and all of a sudden I was able to boot into LFS. Needles to say that you'll also have to change your /etc/fstab file accordingly. Has been working ever since. I plan to get to the bottom of this but that might take some time.

Just wanted to share this, maybe it works for you the same way. At least, if you don't try, you'll never know.

Kind regards,

Eric
 
Old 05-14-2010, 03:19 AM   #6
Lyle
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Quote:
Originally Posted by EricTRA View Post
Hi,

I recently finished the LFS 6.6 book and encountered booting problems too. Although my hard disk also got detected as hda, I was unable to boot into my LFS. After some trying I changed root=/dev/hda1 to root=/dev/sda1 (don't ask me why I did such an illogical thing because I just don't know) and all of a sudden I was able to boot into LFS. Needles to say that you'll also have to change your /etc/fstab file accordingly. Has been working ever since. I plan to get to the bottom of this but that might take some time.

Just wanted to share this, maybe it works for you the same way. At least, if you don't try, you'll never know.

Kind regards,

Eric
Thanks, I just tried that--it didn't work, but maybe im doing something wrong. Can you paste your fstab and grub.cnf contents so i can compare?
 
Old 05-14-2010, 03:44 AM   #7
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Hello,

No problem concerning posting the fstab but you'll have to wait until I get home. I'm at the office right now and will be home in about 6 hours. I'll post it then.

Kind regards,

Eric
 
Old 05-14-2010, 05:47 AM   #8
Lyle
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Quote:
Originally Posted by EricTRA View Post
Hello,

No problem concerning posting the fstab but you'll have to wait until I get home. I'm at the office right now and will be home in about 6 hours. I'll post it then.

Kind regards,

Eric
ok, thanks.
 
Old 05-14-2010, 08:34 AM   #9
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Install grub on hd0. Reread my last post. Your grub line for LFS should look like this (Presuming your kernel is in /boot

kernel /your_kernel root=/dev/sda1 ro

If for some reason you used the old ide driver, sda would be hda. This means you have installed lfs on the first partion of the first disk. Is this whet you have actually done? What did you use as a host system?
 
Old 05-14-2010, 09:46 AM   #10
Lyle
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Quote:
Originally Posted by business_kid View Post
Install grub on hd0. Reread my last post. Your grub line for LFS should look like this (Presuming your kernel is in /boot

kernel /your_kernel root=/dev/sda1 ro

If for some reason you used the old ide driver, sda would be hda. This means you have installed lfs on the first partion of the first disk. Is this whet you have actually done? What did you use as a host system?
The lfs partition is listed as /dev/hda1 in fdisk and I used lenny as the host.

This is my partition table as seen from lenny, Sabayon calls them sda, but ive tried both in LFS.
Code:
-l

Disk /dev/hda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x95aa95aa

   Device Boot      Start         End      Blocks   Id  System
/dev/hda1               1         729     5855661   83  Linux
/dev/hda2            3396        4830    11526637+  83  Linux
/dev/hda3            4831        9729    39351217+   f  W95 Ext'd (LBA)
/dev/hda4   *         730        2034    10482412+  83  Linux
/dev/hda5            4831        4960     1044193+  82  Linux swap / Solaris
/dev/hda6            4961        8291    26756226   83  Linux
/dev/hda7            8292        9729    11550703+  83  Linux

Partition table entries are not in disk order
Ive also tried reinstalling the Sabayon bootloader but it doesn't recognize LFS apparently.

Last edited by Lyle; 05-14-2010 at 09:48 AM.
 
Old 05-14-2010, 10:36 AM   #11
EricTRA
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Hi,

As promised.
Code:
/dev/sda1     /          ext3    defaults    1     1
/dev/sda5     swap       swap    pri=1       0     0
proc          /proc      proc    defaults    0     0
sysfs         /sys       sysfs   defaults    0     0
devpts        /dev/pts   devpts  gid=4,mode=620   0     0
tmpfs         /dev/shm   tmpfs   defaults    0     0
Hope that helps.

Kind regards,

Eric
 
Old 05-14-2010, 11:11 AM   #12
Lyle
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Quote:
Originally Posted by EricTRA View Post
Hi,

As promised.
Code:
/dev/sda1     /          ext3    defaults    1     1
/dev/sda5     swap       swap    pri=1       0     0
proc          /proc      proc    defaults    0     0
sysfs         /sys       sysfs   defaults    0     0
devpts        /dev/pts   devpts  gid=4,mode=620   0     0
tmpfs         /dev/shm   tmpfs   defaults    0     0
Hope that helps.

Kind regards,

Eric
thanks
 
Old 05-15-2010, 04:13 AM   #13
business_kid
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This query is about LFS, which is about making a second system from the first one

Is this /etc/fstab from your LFS, or /etc/fstab from your host system?
 
Old 05-15-2010, 04:18 AM   #14
EricTRA
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Hi business_kid,

If you're referring to me posting my fstab, then yes, this is from my LFS system, which I finished last Sunday and that boots perfectly. Why do you ask? I'm aware that this thread is about LFS, why would you think I am not?

Kind regards,

Eric
 
Old 05-15-2010, 04:22 AM   #15
EricTRA
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Quote:
Originally Posted by business_kid View Post
This query is about LFS, which is about making a second system from the first one

Is this /etc/fstab from your LFS, or /etc/fstab from your host system?
I thought LFS is all about building a new system from scratch, not making a second one from the first, but using a host system to be able to use the necessary tools in it (toolchain and build environment) to put together a new system. At least that's the way I see it.

Kind regards,

Eric
 
  


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