Kernel Panic - not syncing: VFS:

Bruce Dubbs bruce.dubbs at gmail.com
Sun Feb 7 10:05:06 PST 2010


Aditya Bankar wrote:

>>>> I am getting this problem while launching the new LFS 6.5:
>>>>
>>>> Root NFS: No NFS server available, giving up
>>>> VFS: Unable to mount root fs via NFS trying floppy
>>>> VFS: Cannot open root device "sda6" on unknown_block (2,0)
>>>> Please append a correct "root=" boot options; here the options
>>>> Kernel Panic - not syncing: VFS: Unable to mount root fs on unknown_block 
>> (2,0)
>>>> I did not install grub. I have instead added new entries in the host system's
>>>> menu.lst. Since my LFS partition is /dev/sda6 as seen on host system I have
>>>> added the following to menu.lst
>>>> title           LFS6.5
>>>> root            (hd0,5)
>>>> kernel          /boot/lfskernel-2.6.30.2 root=/dev/sda6

It's a kernel problem, not a boot problem.  The messages above are from 
the kernel so it was loaded properly.  You might want to add ro to the 
kernel line though.

>>>> A result of grep on my .config file is the following:
>>>> grep NFS /mnt/lfs/compilation/linux-2.6.30.2/.config
>>>> CONFIG_NFS_FS=y
>>>> CONFIG_NFS_V3=y
>>>> CONFIG_NFS_V3_ACL=y
>>>> CONFIG_NFS_V4=y
>>>> CONFIG_ROOT_NFS=y
>>>> CONFIG_NFSD=y
>>>> CONFIG_NFSD_V3=y
>>>> # CONFIG_NFSD_V3_ACL is not set
>>>> # CONFIG_NFSD_V4 is not set
>>>> CONFIG_NFS_ACL_SUPPORT=y
>>>> CONFIG_NFS_COMMON=y

Until you get going, disable these.  It just complicates things.

>>>> Why don't we use initrd in lfs?

Because it is an extra complication for a basic system like LFS.

>>> BTW, I have compiled SATA drivers.

>> We need some more information. Are you trying to mount an NFS share as 
>> your root partition? If so I think you'll need to make an initrd.
>> Or is / a filesystem on /dev/sda6? If so what filesystem? Did you 
>> compile support for it into the kernel?

> I didn't try to deviate from what the book says, except that I didn't
> install grub. So I am not trying to mount an NFS share as the root
> partition.

> The partition /dev/sda6 is ext3 filesystem which has to be mounted on /. 
 > I had chosen to compile EXT3 support. See below:
> grep -i ext3 /mnt/lfs/compilation/linux-2.6.30.2/.config 
> CONFIG_EXT3_FS=y
> # CONFIG_EXT3_DEFAULTS_TO_ORDERED is not set
> CONFIG_EXT3_FS_XATTR=y
> CONFIG_EXT3_FS_POSIX_ACL=y
> CONFIG_EXT3_FS_SECURITY=y

Go ahead and post your full config file at http://pastebin.com/ and let 
us know the url so we can take a look.  I suspect some underlying 
drivers are missing.

The output of lspci from your host would be helpful too.

   -- Bruce



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