[lfs-support] Kernel panic lfs-7.2

Bruce Dubbs bruce.dubbs at gmail.com
Thu Oct 25 14:46:47 PDT 2012

spiky wrote:
> Hi
> Ok I,m having real trouble booting my lfs system. Long storey with lfs
> 7.2 wont boot, I have now dd a working lfs-7.0 system, from another
> laptop which I have done before. on to this laptop replacing 7.2.
> I adjusted fstab file as needed for new partitions.
> I have tried booting from grub prompt (host grub)
> set root=(hd0,3)
> linux /boot/vmlinuz-3.3-rc1-lfs-7.0
> boot
> I get a kernel panic
>    "VFS unable to mount root fs via NFS trying floppy
> VFS cannot open root device "(null)" or unknown-block(2,0)
> please append a correct "root=" boot option here are availble partitions"
> then it lists the sda partitions.
> I got the same panic with the lfs 7.2 install, I have rebuilt the kernel
> many times different configurations.
>     I have built lfs since 6.7 and always got them to boot, this is the
> 1st time I have built on this laptop, Nothing special about this laptop.
> Would really like to get this fixed Thks

It sounds like you are telling the kernel the wrong root partition in 
grub (or not specifying any root partition).  For example:

menuentry "BLFS Dev (LFS-SVN-20121013), Linux 3.6.2" {
         linux   /vmlinuz-3.6.2-lfs-20121013 root=/dev/sda16 ro

GRUB is finding the kernel, but the kernel is not finding the right root 


menuentry "BLFS-7.2" {
   set root=(hd0,3)
   linux /boot/vmlinuz-3.3-rc1-lfs-7.0 root=/dev/sda3 ro

   -- Bruce

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