Re: What means that: FATAL: udev is already active on /dev/.

[Cameron Hutchison <camh+dl@xdna.net>]

Once upon a time Jim McCloskey said...
> 
>   |> FATAL: udev is already active on /dev/
> 
> I've been banging my head against this problem for a week and a half
> now. I get the error message at boot time, but udev (as far as I can
> tell) seems to work as it is supposed to.

Are you sure udev is working? I only ask because of the code in the
initscript you quoted has an "exit 1" after the fatal message you are
getting.

Check /proc/mounts (cat /proc/mounts). You should have a couple of lines
like this:

/dev/root /.dev ext3 rw,noatime 0 0
none /dev tmpfs rw 0 0

The first is the bind mount that relocates the /dev on the disk to
/.dev. The second is the mount of tmpfs on /dev which is where udev
creates the nodes.

I suspect you have a .udev.tdb on your filesystem, but when you delete
it you are deleting it from tmpfs. This does not make complete sense
though, but it's all I can think of.

What I'd do is boot the system with 'init=/bin/sh' on the boot command
line. This will get you into your system without any /etc/init.d scripts
running. Then remount root as read/write:

# mount -o remount,rw /

Then delete /dev/.udev.tdb

# rm -f /dev/.udev.tdb

Then remount read-only and retstart your machine:

# mount -o remount,ro /

<press reset>

> But even deleting this file has no effect on whether or not the error
> message appears at next boot.
> 
> My own system has a fully-populated /dev/ directory and an empty
> /.dev/ directory.

This is what's wierd. A fully populated /dev directory implies udev is
not running. The error message you get implies udev is not running. That
/.dev is empty implies udev is not running. This means /dev should be
your real on-disk filesystem. Therefore, deleting /dev/.udev.tdb should
set things right and the steps I've outlined above should not be necessary.

Yet, you state that that has not worked. Does /dev/.udev.tdb return
every boot?

> Where is any of this documented????

Whenever I need to know something about udev, I read the scripts that
are readable and google for the rest. It doesn't help that udev is
constantly evolving (perhaps it has slowed down now), so google can
return out-of-date information.