Compile different Kernel versions using Qubesbuilder package?

User Support
1

Hello Everybody,

I am having partial success using the instructions in h**ps://www.qubes-os.org/doc/qubes-builder/ to compile a custom kernel. After issuing make linux-firmware linux-kernel the kernel compiles successfully (compiled kernel rpm install in dom0 still fails. See Related Notes below).

However, the compiled kernel version is not equal to kernel-latest. The compiled version is stable-5-4-80-1. I would like to compile v5.8.16-1-latest.

@fepitre, I know you have kindly suggested in https://github.com/QubesOS/qubes-issues/issues/5453 that:

“You can bump the rel file h**ps://github.com/QubesOS/qubes-linux-kernel/blob/master/rel to ensure to upgrade properly your dom0 version.”,

but I don’t know what “bump[ing] the rel file” means.
Since I don’t want to pester that issue thread with unrelated kernel compilation problems, I would like to kindly ask you if you could elaborate here a little further.

In the meantime, I’ve tried setting BRANCH_linux_kernel = v5.8.16-1-latest in builder.conf but I get a “Tag has the wrong hash” verification error during Updating sources for linux-kernel. I’ve tried setting CHECK=insecure-no-check below line NO_SIGN=1 but the error persists.

Any other suggestions would be greatly appreciated. Thanks in advanced for your support

Related Notes:

  1. The instructions in h**ps://www.qubes-os.org/doc/qubes-builder/ produce a Zstd rpm which dom0 then fails to install in dom0. Researching I found out there is a dirty fix in https://groups.google.com/g/qubes-users/c/_VCVM9AdhEM/m/RdgZKa4yAQAJ

sed -i ‘/%define version/a%define _binary_payload w6.gzdio’ qubes-src/linux-kernel/kernel.spec.in

  1. This user also mentions that “qubes-src/linux-kernel has questionable rules for selecting
    linux-.tar.gz (which fails) rather than linux-.tar.xz.” and proposes the following fix:

sed -i ‘s/^SRC_FILE.*gz/SRC_FILE := linux-${VERSION}.tar.xz/’ qubes-src/linux-kernel/Makefile
sed -i ‘s/^Source0.*gz/Source0: linux-%{upstream_version}.tar.xz/’ qubes-src/linux-kernel/kernel.spec.in

Both Notes 1 and 2 were needed to install the compiled kernel successfully in dom0.

Regards,
SU

2

It means you simply need to edit the rel file and change current number to 2. It will have the resulting version: 5.8.16-2

In your builder.conf, BRANCH_ refers to branch only so it means for kernel-latest to use master branch: BRANCH_linux_kernel = master. Then, you can make get-sources again in qubes-builder and do your changes in qubes-src/linux-kernel like modifying config-base or config-qubes etc. After your modifications done, simply run make linux-kernel and you would be able to find the resulting build into qubes-packages-mirror-repo/dom0-fc25.

3

Thank you for the explanation and great help fepitre, this is now clear.

Regards,
SU