Regression in 7.1-rc1 in booting Ubuntu distro kernel

[Aaron Ma]

Hi Steve,

This error is indicated that rootfs is not loaded, please check if the
kernel module package is installed and initramfs is made for the new
kernel.

Regards,
Aaron

On Wed, May 6, 2026 at 2:16 PM Steve French <smfrench at gmail.com> wrote:
>
> I notice failures in booting Ubuntu 25.10 on my Lenovo Thinkpad laptop
> since 7.1-rc1 kernel.  I have not seen this error before.
>
> "KERNEL PANIC! Please reboot your computer.  VFS: Unable to mount root
> fs on unknown-block(0,0)"
>
> which doesn't make any sense because that isn't the root fs.  /etc/fstab shows:
>
> /dev/disk/by-uuid/6ca90829-120e-4d09-be02-46422daffdcd / ext4 defaults 0 1
>
>
> The last kernel that booted successfully was the daily build from the
> day before (4/26/26
> https://kernel.ubuntu.com/mainline/daily/2026-04-26/).  It also fails
> on current daily builds and on 7.1-rc2 kernel
> (https://kernel.ubuntu.com/mainline/v7.1-rc2/) so I have been stuck
> doing my testing on out of tree builds booting from a few weeks old
> kernel.
>
> Any ideas how to find out what regressed in the mainline kernel in
> 7.1-rc1 (or in the ubuntu mainline daily build) or how to workaround
> or debug this?
> --
> Thanks,
>
> Steve
>
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