Re: custom kernel without initrd and with udev
Hi Pascal,
Thanks for your input.
On Sat, Jul 07, 2012 at 11:16:26AM +0200, Pascal Hambourg wrote:
> Hello,
>
> Dom a ?crit :
> > On 07/07/12 00:08, Mike McClain wrote:
> >>
> >> While surely no expert I've been building my own kernels for
> >> a long time with little trouble but with a recent install of
> >> 'Squeeze' I'm stumped. I've built, reconfigured, built again for
> >> several days now. No joy. I've spent hours Googling for any and
> >> everybody's thoughts on the error: 'Kernel panic - not syncing:
> >> VFS: Unable to mount root fs on unknown-block(0,0)' with little luck.
>
> What are the lines preceding the error ?
VFS: Cannot open root device "sdb5" or unknown-block(0,0)
Please append correct "root=" boot option; here are available partitions:
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
Note that there are no 'available partitions' listed though before I reach this
point the grub commandline will show that all partitions on both drives are
recognized by grub.
>
> >> Is anyone running a custom kernel without an initrd with udev?
>
> Yes, I am. I am also running a custom kernel without an initrd and
> without udev (which was one purpose of the custom kernel, no dependency
> on udev).
So you are running two systems one with udev and one without?
If so, on the one without did you populate /dev by hand?
On the one with udev what does your grub.cfg entry look like?
>
> > Yes, I am. Although I believe there are some circumstances where this
> > may not be possible. eg. where something else needs to be started in
> > order to mount the root filesystem first.
>
> Such circumstances include :
> - root is on a software RAID (md) volume with 1.x meta-data
> - root is on an LVM volume
> - root is on an encrypted volume
The above don't apply but this next one got me.
> - root is specified by the bootloader as a LABEL or UUID
>
> >> Any tips, pointers will be appreciated.
> >
> > Make sure that *all* filesystem and device drivers for your root
> > partition are compiled directly into the kernel - not as modules.
>
> Also make sure that the root= option passed by the bootloader to the
> kernel command line specifies the root as a device name /dev/sdXY and
> not as a LABEL or UUID which the kernel does not understand.
Thanks again for your input,
Mike
--
Satisfied user of Linux since 1997.
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