MPTCP kernel cannot be loaded: goes to busybox

[Yufei-Yan]

I'm using newest Dell XPS 13 model. Installed Ubuntu 20.04 along with pre-installed Windows 10.
After it boots and select MPTCP kernel, it says:

Spectre V2 : WARNING: Unprivileged eBPF is enable iwth eIBRS on,
data leaks possible via Spectre v2 BHB attacks
hw perf events fixed 4 > max(3), clipping!

Gave up waiting for suspend/resume device
Gave up waiting for root file system device. Common problems:
 - Boot args (cat /proc/cmdline)
  - Check rootdelay= (did the system wait long enough?)
 -Missing modules (cat /proc/modules; ls /dev)
ALERT! UUID=<the uuid> does not exist. Dropping to a shell!

BusyBox v1.30.1 (Ubuntu 1:1.30.1-4ubuntu6.4) built-in shell (ash)
Enter 'help' for a list of built-in commands

(initramfs)

I have disabled Secure Boot option in BIOS, but it does not solve the problem.

However, the older laptops do not have this issue.
I don't know if it is caused by some secure check from the hardware or by the dual boot?

Please help.
Thanks.

[matttbe]

Hello,

Which kernel did you install exactly?

I don't know if it is caused by some secure check from the hardware or by the dual boot?

The kernel we build are not signed and might then fail some security checks if any.

Gave up waiting for suspend/resume device
Gave up waiting for root file system device. Common problems:

• Boot args (cat /proc/cmdline)
• Check rootdelay= (did the system wait long enough?)
  -Missing modules (cat /proc/modules; ls /dev)

As written there, did you install the kernel modules (so all .deb packages we built)?

ALERT! UUID= does not exist. Dropping to a shell!

Maybe you have a filesystem not supported by our kernel? What kind of partitions you have?

[Yufei-Yan]

Hey @matttbe ,

Thanks for the reply.

The kernel we build are not signed and might then fail some security checks if any.

I checked the issue online, and people say I should turn off the security boot option. I disabled it in BIOS, but it did not solve the issue. The old dell laptops have no problems, so I guess it is caused by some new Dell mechanism in BIOS or somewhere else.
I don't know how to sign it. If possible, could you provide a link for instruction?

Which kernel did you install exactly?

The current running kernel is 5.14.0, and mptcp kernel is 4.19.234.

As written there, did you install the kernel modules (so all .deb packages we built)?

I installed all the .deb files.

Maybe you have a filesystem not supported by our kernel? What kind of partitions you have?

/ and /home are both ext4. And the UUID points to / partition.

[matttbe]

The kernel we build are not signed and might then fail some security checks if any.

I checked the issue online, and people say I should turn off the security boot option. I disabled it in BIOS, but it did not solve the issue. The old dell laptops have no problems, so I guess it is caused by some new Dell mechanism in BIOS or somewhere else. I don't know how to sign it. If possible, could you provide a link for instruction?

Sorry but I don't know what to say: there is no link with MPTCP :)
Maybe after having disabled secure and fast boot options, you need to use the 5.14 kernel, re-launch sudo update-grub command and reboot on the MPTCP kernel?

If not, best to ask for help elsewhere as it is not linked to network issues :-/

Which kernel did you install exactly?

The current running kernel is 5.14.0, and mptcp kernel is 4.19.234.

It should contain many backports but maybe you need new drivers not available in v4.19?

Can you try to install an "Ubuntu Mainline" kernel? e.g. https://kernel.ubuntu.com/~kernel-ppa/mainline/v4.19.234/

These kernels are not signed I think but they have maybe an updated kernel config to support new HW.

If it is not enough, can you try with a v5.4 kernel? e.g. https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.4.187/

As written there, did you install the kernel modules (so all .deb packages we built)?

I installed all the .deb files.

👍

Maybe you have a filesystem not supported by our kernel? What kind of partitions you have?

/ and /home are both ext4. And the UUID points to / partition.

OK, nothing exotic here.

[Yufei-Yan]

I tried all your solutions. The problem is still not solved.
However, after installing the two unsigned kernel you mentioned, it will have the same issue. Looks like it is caused by the signature.

I'm wondering if it could solve the issue when I remove Window 10 and install Ubuntu only.

[matttbe]

However, after installing the two unsigned kernel you mentioned, it will have the same issue. Looks like it is caused by the signature.

There are maybe more options to disable on your BIOS? But hard for me to help you more here.

I'm wondering if it could solve the issue when I remove Window 10 and install Ubuntu only.

Good question. I have an older XPS 13 but I got it without Windows. I had to disable secured boot and fast boot to play with kernels I think but that was enough at that time.
Maybe an option to remove something from Windows' settings?
Maybe an option to switch to a "BIOS" mode instead of "UEFI"?

Or trying to sign the kernel? I never tried but there is a Windows app apparently: https://wiki.ubuntu.com/UEFI/SecureBoot/Signing