# Kernel panic  VFS: unable to mount root device

## incubator

I get a kernel panic at boot

VFS: unable to mount root device  "hda3" (303)  or unknown-block(3,3)

You did not append a proper "root=" boot option

and the thing is> I did :s

my lillo.conf is an exact copy from the one in the installation manujal, only adapted several months ago to work on my system, and it did but now after reinstalling gentoo (after reformatting hda3 to reiser4) it wont  :Sad: 

kernel: nitro-sources-2.6.9-r4

boot loader: LILO

lilo.conf:

```

boot=/dev/hda

map=/boot/map

install=/boot/boot.b

prompt

timeout=50

lba32

default=linux

image=/boot/bzImage

              label=linux

               read-only

               root=/dev/hda3

```

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## neilhwatson

When you ran lilo were there any errors?   You formated your / partition to reiser4?  Does your kernel support reiser4 (not reiserfs as that is reiser3)?

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## incubator

kernel supports reiser4, as i checked the options and i formatted my other disk with that kernel before reinstallation

i received no errors at all whe running lilo

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## neilhwatson

Have you recetly switched from DevFS to Udev?

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## incubator

devfs is sttill switched on  but i have no idea what udev is or where is can be found in kernel config :s

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## neilhwatson

Use a rescue disk and determine if the hard drive is healthy.

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## incubator

fs is consistant i got as message

both root and boot partgition  are clean and consistant (boot = ext3)

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## neilhwatson

That leaves out all the usual suspects.  You may have missed something during your install.  Using the Gentoo disk perform a chroot (be sure to follow ALL of the steps) and run lilo again.

Is /boot a separate partition?  If so, what is the filesystem?

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## incubator

i always do

```

mount /dev/hda3 /mnt/gentoo

mount /hda1 /mnt/gentoo/boot

swapon /dev/hda2

chroot /mnt/gentoo /bin/bash

mount -t proc proc /proc

env-update && source /etc/profile

#cp or resolv not needed for this operation

# edit /etc/lilo.conf

/sbin/lilo

exit

#umount everything

reboot

```

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## dsd

the problem suggested here is a kernel (or kernel configuration) issue- the kernel doesn't know of any driver that has advertised the existance of hda or hda3. 

make sure you have support for your ide controller compiled into the kernel.

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## incubator

CONFIG_BLK_DEV_IDE=y

CONFIG_BLK_DEV_IDEDSK=y

so yes, i compiled IDE support in the kernel

note  my drive never was en never is scsi

so this is nbot the issue either (as i have reaqd on many articles)

adding

append="root=/dev/hda3 devfs=nomount"

did not solve it either

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## dsd

what about support for your ide controller? and how about generic ide?

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## incubator

generic is enabled but what about the other option? where can i fi,d that?

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## incubator

if you meant  the SIS5573  in my case then yes.

but i now also enabled SCSI emulaton (for the hell of it)

and now  I receive end_request: I/O Error , dev hda, sector 192743994

hda: bad access: block=....  count=4

and aqfter that still the kernel ppanic: not syncing: VFS: unable to moiunt root fs on unknown-block(3,3)

for some reason i now get enerror  UDF-fs . no partition found

an di did not compile udf in kernel becquse i know nbot what iit is and never used  it

wheni scroll a bit to above i also see the following errors:

devfs_mk_dir: invalid argument, <6> hda: hda1, hda2, hda3

and <4> devfs_mk_dev: could not apppend to parent for / disc hdb:

hdb1

dewvfs_mk_dev: could not append to parent for /part1

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## incubator

i cpoied the n2.6.8-nitro5 kernel from the cd to my boot and now nhe boots ;D

i just dont know what misconfiguratio  there was with the .9, or if there is a bug in the kernel

though i would like to know how to fix that thougth  (or if i can extract the .config from this compiled kernel from the nrescue cd

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## incubator

ok, got things fixed now, thank god the livecd had a copy of its kernel config file  :Smile: 

i used that, cleaned it out a little and now I fihnally got a worlking kernel with DevFS  :Smile: 

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