[SOLVED] Migrated rootfs to a new, booting gets stuck at USB

shazow · Last edited by shazow on Wed Jul 23, 2014 6:04 am; edited 3 times in total

I installed a new SSD and after some partitioning issues I finally got it to work. I used rsync to move most of the rootfs over, excluding things like /dev, /proc, etc of course. Grub2 boots just fine, gives me the correct options after I updated it, but half way through the booting—right after the USB stuff is wrapped up—it hangs.

Looks something like this... (taken from dmesg, so sans the timestamps in reality)

shazow · Posted: Wed Jul 23, 2014 4:27 am Post subject:

Update: Looks like it's not entirely frozen. If I unplug/plug USB devices, this will get printed in the output. So it's still processing events. It's just that whatever is supposed to happen next is not happening.

Any idea what's missing? Is there any way to increase verbose/debugging output? I tried adding `verbose` to the `linux` boot line but it didn't do anything.

the.root · Posted: Wed Jul 23, 2014 4:38 am Post subject:

I assume you created the /dev/, /sys, /proc directories with proper permissions?

It's been many years since i've tried a straight rsync copy, but if I recall correctly I had a similar issue of it hanging during boot. It was either my /dev wasnt there or some device in /dev wasnt there that needed to be - before udev would mount it. It probably doesn't apply, just figured I'd mention it. You can try copying over your old /dev to your new drive then giving it a go. I just booted off a liveusb and checked out my laptop root partition and /dev is populated even though it didn't boot to properly mount udev there. Also the stage3 tar contains /dev entries.

FYI Your pastebin link "has been removed".
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Ps = (1.5 x 6 x .75) / {(4/3) (pi) [(31.039 x 10^15) (46.5 x 10^9)]^3}
Seems like a waste..

shazow · Posted: Wed Jul 23, 2014 4:43 am Post subject:

shazow · Posted: Wed Jul 23, 2014 4:46 am Post subject:

Nope, fixing /run did not do the trick.

Will continue messing with things.

Seeing a lot of forum posts saying "udev is broken for me with the new version", maybe worth trying to downgrade...

the.root · Posted: Wed Jul 23, 2014 4:48 am Post subject:

Did you try copying the contents of your old /dev to your new /dev? I want to say thats what fixed it for me, hard to remember though. Or maybe using the /dev from a stage3 tarball or whatever else you have available.
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Ps = (1.5 x 6 x .75) / {(4/3) (pi) [(31.039 x 10^15) (46.5 x 10^9)]^3}
Seems like a waste..

shazow · Posted: Wed Jul 23, 2014 6:05 am Post subject:

Aha, rsync'ing the contents of /dev totally did the trick, thank you kind the.root!

Marked as solved.

Goverp · Advocate Joined: 07 Mar 2007 Posts: 2006

I know this is a necropost but I've had the exact same problem, and fixed it using an up-to-date version of the above solution. It's a fair bit shorter, as it turns out /dev needs contain only one thing, a console.
Context:
I wanted to resize and change some options on my rootfs. So I made a tarball of / --one-file-system, recreated the partition and untarred the tarball (all these shenanigans using the Admin version of the Gentoo install CD on a USB key).
Problem:
On reboot, it the last line of console output before it hung was about USB device 1-1.4. Comparing with the last successful boot, the next line should have been "udev starting".
Solution:
Rebooting into the installation CD and mounting the partition at /mnt/gentoo, I could see that /mnt/gentoo/dev contained a file "console". Aha, not a character device node. Replacing it fixed the problem - udev clearly needs a console before it starts.
Note: don't cut and paste the following - I've typed it from memory, not copied it from real life:

Hu · Moderator Joined: 06 Mar 2007 Posts: 21631

I suspect tar did not copy anything from /dev, and instead that file console was created because some program did udev >/dev/console expecting that such a redirect would open the device node console. Instead, nothing was at that path, so output was redirected to a newly created file named console.

Goverp · Advocate Joined: 07 Mar 2007 Posts: 2006

Well, whatever the cause, /dev needs some things in it for udev to start. In fact, for it to work properly, it's more than just /dev/console - I forget the message, but something else wasn't working right. The modern solution is to select CONFIG_DEVTMPFS_MOUNT in the kernel config. That leaves a populated /dev for udev to play with.
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Greybeard