Booting New LFS System Ends in Kernel Panic
farmerdan at i-rule.net
Sun Apr 3 14:32:14 PDT 2005
Just completed an LFS 6.0 build--well Friday night. Each time I try to
boot I get:
Kernel panic:VFS:Unable to mount root fs on unkown-block (3,67)
I know that this subject is a FAQ. I have made sure that ext2 and ext3
are compiled into the kernel. In addition, the drivers for the
harddrives are compiled into the kernel.
I have Googled on this error and it seems that there are any one of over
a million suggestions on how to fix this--most seem inappropriate for my
situation. At this point in time I don't know whether I have a GRUB or
kernel situation. I can boot both Mandrake 10.1 and Windows with no
The only difference between Mandrake and LFS is that Mandrake uses an
initrd. Since I made the "title" entries different for each menu.lst
that I have (LFS_6.0 in Mandrake and LFS 6.0 in LFS), I discoverd that
I'm booting from the Mandrake partition. I have made the LFS partition
a primary and have used "makeactive" on boot. All to no avail. The
entries for Mandrake and LFS are identical in each distro--except for
the title. Here they are:
> title Mandrake
> kernel (hd1,0)/boot/vmlinuz root=/dev/hdb1 acpi=ht resume=/dev/hdb6
> splash=silent vga=788
> initrd (hd1,0)/boot/initrd.img
> title LFS_6.0
> root (hd1,2)
> kernel /boot/lfskernel-220.127.116.11 root=/dev/hdb3
Just to make sure everything was in place I ran:
in the grub shell. It didn't complain about anything but not being able
to "embed" the images and gave the message "that's not fatal." It
recognized all the appropriate filesystems--ext2.
The lines of kernel messages I get just before the panic are:
< NET: Registered protocol family 1
< NET: Registered protocol family 17
< NET: Registered protocol family 15
<VFS: Cannot open root device "hdb3" on unknown-block (3,67)
<Please append a correct "root= " boot option
<Kernel panic:VFS:Unvable to mount root fs on unkown-block (3,67)
In <dmesg> for booting Mandrake the same section gives:
<NET: Registered protocol family 1
<BIOS EDD facility v0.16 2004-Jun-25, 2 devices found
<md: Autodetecting RAID arrays.
<md: autorun ...
<md: ... autorun DONE.
<RAMDISK: Compressed image found at block 0
<VFS: Mounted root (ext2 filesystem).
I don't know if this is relevant. It's different. I can see the initrd
mount. But once again, I have seen no posts on this list with a similar
situation, so it must be something I have done.
I also thought about room to mount the root filesystem. I have 1G of
RAM and my SWAP is 1G also. The appropriate results of df are:
</dev/hdb3 3.8G 1.1G 2.6G 30% /mnt/lfs
and the results of <ls -alQ /mnt/lfs/boot are:
drwxr-xr-x 3 root root 4096 Apr 3 13:06 "."/
drwxr-xr-x 22 root root 4096 Apr 3 11:08 ".."/
-rw-r--r-- 1 root root 26901 Apr 3 13:06 "config-18.104.22.168"
drwxr-xr-x 2 root root 4096 Apr 3 13:11 "grub"/
-rw-r--r-- 1 root root 1685274 Apr 3 13:05 "lfskernel-22.214.171.124"
-rw-r--r-- 1 root root 826198 Apr 3 13:06 "System.map-126.96.36.199"
so it looks like there's enough room to expand the kernel and mount the
I must confess that I have reached the limits of my knowlege. I have
followed the book verbatim and didn't have any problems that I couldn't
resolve. Well, I just lied. When I first began my build I mounted
/mnt/lfs as an ext3 instead of an ext2 partition. But that shouldn't
affect things, should it?
In running Mandrake I have noticed weird things with 188.8.131.52. And I
have not ever gotten it to run on my laptop. Would compiling at 2.6.10
or 2.6.11 be helpful?
If it's something I have compiled into the kernel, something that should
be in the kernel or something that's not a module, I sure don't
Please share your ideas with me regardless of how mundane they seem.
I'm getting a little desperate. I will surely appreciate any help and
will try anything short of shooting the PC. :)
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