cloud-initramfs-copymods sometimes breaks systems with self-contained kernel/initrd

[TJ]

I've been working with a colleague with an ubuntu-server install in a Xen virtual machine. The install doesn't use an external kernel/initrd.img but due to having package ubuntu-server installed also installs cloud-initramfs-copymods.

The initial report was the system suffering repeated loss of the xenfs.ko module after reboots. Eventually tracked down to /lib/modules/ being a tmpfs which is created by

/usr/share/initramfs-tools/scripts/init-bottom/copymods

There's a bug which causes it to unconditionally create the tmpfs mount on /lib/ even when the kernel command-line does not contain "copymods=force".

We're trying to figure out how this is getting triggered. On the face of it the only way it could occur is if the rootfs is missing /lib/modules/ OR is missing /lib/modules/$myver or the rootfs hasn't been mounted to $rootmnt at the time this script executes.

This was an encrypted separate /boot/ and / install using debootstrap of ubuntu-server + the kernel packages due to the 20.04 live server installer not being able to deal with this layout. Therefore there may be some quirk of this method triggering the issue, although it is unclear what.

[Shura1oplot (s0meuser)]

I have the same issue with ubuntu server (focal) on Raspberry Pi 4. Removing the package cloud-initramfs-copymods solves the problem.

[Lucas Kanashiro (lucaskanashiro)]

Could you please provide any logs for us to inspect? Also the content of /proc/cmdline if possible?

Another thing you could do here is to test it with Hirsute or Impish to see if you get the same problem. In Focal, we have cloud-initramfs-tools/0.45ubuntu1 and in the latest releases we have cloud-initramfs-tools/0.47ubuntu1, maybe the fix is in there already.

For now, I marking this bug as Incomplete but once you add more information please set it back to New and we will revisit it.

[Launchpad Janitor (janitor)]

[Expired for cloud-initramfs-tools (Ubuntu) because there has been no activity for 60 days.]