Introduction

By default, Ubuntu systems run with the Ubuntu kernels provided by the Ubuntu repositories. However it is handy to be able to test with unmodified upstream kernels to help locate problems in the Ubuntu kernel patches, or to confirm that upstream has fixed the issue. To this end we now offer select upstream kernel builds. These kernels are made from unmodified kernel source but using the Ubuntu kernel configuration files. These are then packaged as Ubuntu .deb files for simple installation.

We currently build five sets of upstream kernels. All formal tags from Linus' tree and from the stable trees, plus:

1. the daily tip of Linus' linux kernel source tree,

2. the tip of the drm-next head of Dave Airlie's linux repository daily,

3. the tip of the drm-intel-next head of Keith Packard's linux repository daily,

4. the tip of the master branch of the debloat-testing tree daily,

5. tags from the combined v2.6.32.x.y tree (by StefanBader) which is v2.6.32.x with DRM from 2.6.33.y.

This makes these kernels closer to the Lucid kernels which are based on 2.6.32 kernels with DRM backported from the 2.6.33 series.

Upstream kernels archive

The upstream kernels archive is located at the URL below. There is a directory for each build. Note, if you are testing for a bug, please do not use the daily folder, but use the latest mainline kernel at the top:

• http://kernel.ubuntu.com/~kernel-ppa/mainline/?C=N;O=D

The tagged releases are found under a directory matching their tag name and which kernel configuration they were built with (<tag>-<series>). Daily releases are found in the daily sub-directory named for the date they were made.

Each build directory contains the header and image .deb files for the generic flavour i386 and amd64 architectures.

Installing upstream kernels

To boot into an upstream kernel you only need to download and install the *image*.deb package that corresponds to your architecture. In addition, if you need to build any external modules you also need the correspinding headers-<kernelname>_<architecture>.deb and headers-<kernelname>_all.deb packages.

For example, let us use http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.14.4-utopic/.
If you were testing i386, you would want those marked A.
If you were testing amd64, B.
(Use generic kernel unless you have a special need for lowlatency kernel, such as audio production.)

B  linux-headers-3.14.4-031404-generic_3.14.4-031404.201405130853_amd64.deb
A  linux-headers-3.14.4-031404-generic_3.14.4-031404.201405130853_i386.deb
   linux-headers-3.14.4-031404-lowlatency_3.14.4-031404.201405130853_amd64.deb
   linux-headers-3.14.4-031404-lowlatency_3.14.4-031404.201405130853_i386.deb
AB linux-headers-3.14.4-031404_3.14.4-031404.201405130853_all.deb
B  linux-image-3.14.4-031404-generic_3.14.4-031404.201405130853_amd64.deb
A  linux-image-3.14.4-031404-generic_3.14.4-031404.201405130853_i386.deb
   linux-image-3.14.4-031404-lowlatency_3.14.4-031404.201405130853_amd64.deb
   linux-image-3.14.4-031404-lowlatency_3.14.4-031404.201405130853_i386.deb

Once you have those downloaded they will need to be installed using dpkg:

sudo dpkg -i *.deb

When this process completes you should have a new entry on your boot menu representing the upstream kernel. This will appear as an entry like this:

Ubuntu Trusty, kernel 3.14.4-031404-generic

Problems installing an upstream kernel

Some have found issues installing an upstream kernel due to an error. For example:

Error! Bad return status for module build on kernel: 3.7.0-030700rc2-generic (x86_64)
Consult /var/lib/dkms/virtualbox/4.1.18/build/make.log for more information.

This would be due to a conflict with the installed software (VirtualBox, nvidia proprietary drivers, fglrx, wl, etc.). If possible, one would want to uninstall the conflicting package(s) first, then install the upstream kernel. This will allow you to test the upstream kernel, and provide another data point on if the removed software has a relationship to your problem.

Uninstalling upstream kernels

The upstream kernels have their own ABI namespace so they install side by side with the stock Ubuntu kernels (each kernel has a separate directory under /lib/modules/VERSION for example). This means that you can keep several mainline and Ubuntu stock kernels installed at the same time and select the one you need from the GRUB boot menu.

If you would like to uninstall an upstream kernel anyway, first use:

dpkg -l | grep "linux\-[a-z]*\-"

to find the exact name of the kernel packages you want to uninstall, and then do:

sudo apt-get remove KERNEL_PACKAGES_TO_REMOVE

Remember that several packages can belong to one kernel version: common headers, architecture specific headers and the architecture specific image.

Mainline build tool chain

These kernels are built with the tool chain (gcc etc.) from the previous LTS (Ubuntu 8.04/10.04/12.04) depending on version. Therefore, out-of-tree kernel modules built with tools from other versions likely will not work. The file BUILD in later mainline builds detailing what was used.

Mainline kernel mapping to Ubuntu kernel

The Ubuntu kernel is not bit-for-bit the same as the mainline. However, one may find the upstream release that the Ubuntu kernel is based on via the Ubuntu to mainline mapping table.