grub error after kernel update with active root LVM snapshot

archygriswald

2/8/24, 5:41 PM

The situation:

debian 11 with LVM and / is a logical volume: /dev/mainvg/lv-root
created a snapshot of the root partition by doing lvcreate -L5G -n bkp_lvroot -s /dev/mainvg/lvroot

Now I updated the system with apt, a new kernel was installed, but grub-probe failed. Output:

[...]
Setting up linux-image-5.10.0-21-amd64 (5.10.162-1) ...
I: /vmlinuz.old is now a symlink to boot/vmlinuz-5.10.0-20-amd64
I: /initrd.img.old is now a symlink to boot/initrd.img-5.10.0-20-amd64
I: /vmlinuz is now a symlink to boot/vmlinuz-5.10.0-21-amd64
I: /initrd.img is now a symlink to boot/initrd.img-5.10.0-21-amd64
/etc/kernel/postinst.d/initramfs-tools:
update-initramfs: Generating /boot/initrd.img-5.10.0-21-amd64
/etc/kernel/postinst.d/zz-update-grub:
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-5.10.0-21-amd64
Found initrd image: /boot/initrd.img-5.10.0-21-amd64
Found linux image: /boot/vmlinuz-5.10.0-20-amd64
Found initrd image: /boot/initrd.img-5.10.0-20-amd64
Found linux image: /boot/vmlinuz-5.10.0-13-amd64
Found initrd image: /boot/initrd.img-5.10.0-13-amd64
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
grub-probe: error: unknown filesystem.
/usr/sbin/grub-probe: error: unknown filesystem.
Found Debian GNU/Linux 11 (bullseye) on /dev/mapper/mainvg-bkp_lvroot
done
Setting up linux-image-amd64 (5.10.162-1) ...
user:~$

This is the exactly same problem as described on launchpad.
There a reboot solved the problem.

But I am scared to reboot, because the new kernel is already symlinked and grub config generated, as my output above states.

I need advice, guys:
Can I safely reboot or will my system get corrupted when I reboot???

Or should I somehow "revert" to the old kernel first? (how would that be done?)

(BTW: I cannot remove the snapshot, because it is 'in use' and is in active state, lvremove and lvchange do not work)

Any help here is really appreciated

139

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lvm

grub

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update

Score:0

Server

archygriswald

2/10/24, 5:16 PM

Yes, doing a reboot is fine!
This error message does not break grub or the startup process.

(I set up a test environment in a VM at home and provoked the same error, then rebooted, and all was fine.)

Also you can look into /boot/grub/grub.cfg to check if the grub menu entries are correct.

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EN: grub error after kernel update with active root LVM snapshot

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