focal:linux-hwe-5.8 lttng-modules dkms failure

[Khaled El Mously]

Impact: lttng-modules-dkms fail to build on Focal with the linux-hwe-5.8 kernel.

Fix: Use version 2.12.2 instead of 2.11.2. That would bring it in line with the version used in groovy.

Testcase: Attempt to build the currently-available 2.11.2 - observe that it fails. Create a new package using the groovy source package, confirm that it builds and installs successfully. Furthermore, I was able to successfully manually modprobe all the .ko files that were built.

Regression potential: Technically this doesn't work on the 5.8 hwe kernel in focal right now, so it cannot be any more broken than it currently is. The 2.12.2 version is identical to the one currently used in groovy.
EDIT: The upstream lttng-modules project is compatible and buildable on all >3.0 kernels. The new 2.12.2 code should continue to function fine on the 5.4 kernel.

I confirmed that the this latest package builds and loads without any errors or warnings on the 5.4 kernel.

So, there is a small potential for regression on the 5.4 kernel - that would likely indicate an upstream bug in lttng-modules itself.

[Khaled El Mously (kmously)]

The source package is available at:

https://kernel.ubuntu.com/~kmously/lttng-2.12/

[Khaled El Mously (kmously)]

The upstream lttng-modules project is compatible and buildable on all >3.0 kernels. The new lttng-modules 2.12.2 code should continue to function fine on the 5.4 kernel.

I confirmed that the this latest package builds and loads without any errors or warnings on the 5.4 kernel.

Therefore, it is more accurate to say there is a small potential for regression on the 5.4 kernel - and that would likely indicate an upstream bug in lttng-modules itself.