Thursday, 4 November 2021

Re: eBPF support in HWE kernels + userland changes needed

- #1 = Ubuntu HWE kernels aren't being compiled with BTF support, something that is critical for eBPF CO-RE, turning an eBPF object portable among different kernel versions.

Hi Rafael,
glad to "see" you.
It seems pahole is only a build time dependency to enable the kernel
to be able to build this dwarf info.
If it is indeed build-time only then it does not need to pass the MIR process.
As long as the kernel team is happy with using it at build time to
generate this extra data you should be fine.

Hey Christian! Thanks for the reply. Yep, it turns out that kernel team was quicker and I was the one that missed the SRUs. They've done better, preparing pahole 1.21 as SRU for Focal and Bionic:

 dwarves-dfsg | 1.21-0ubuntu1~18.04 | bionic-proposed/universe | source
 dwarves-dfsg | 1.21-0ubuntu1~20.04 | focal-updates/universe   | source
 dwarves-dfsg | 1.21-0ubuntu1~21.04 | hirsute-updates/universe | source
 dwarves-dfsg | 1.21-0ubuntu1       | impish/universe          | source
 dwarves-dfsg | 1.21-0ubuntu1       | jammy/universe           | source

xnox told me he is working in having BTF enabled for 5.4 and 5.8 kernels by EOY (which is very nice for us).

Thanks a lot everyone, sorry for the noise if any, hopefully it will also help others dealing with eBPF. I'll close the bugs I created.