Is it possible to use CO-RE with kernel 4.9?

[tanshihaj]

README.md states that cilium/ebpf support linux kernels 4.9+. However I cannot understand how applyRelocations() should work - BTF supported only form linux kernel 4.18.

Is there any way to load BPF program on 4.9 kernel?

[lmb]

So, bpf2go is a way for you to compile C to BPF and ship it in your go binary. It doesn't have a kernel dependency.

When you say applyRelocations, I'm assuming you're talking about CO-RE? The library allows you to provide your own BTF using ProgramOptions.KernelTypes. You can combine this with btfhub which has BTF for popular distros / older kernels.

[tanshihaj]

When you say applyRelocations, I'm assuming you're talking about CO-RE?

Yes, it seems my issue is connected with CO-RE.

You can combine this with btfhub which has BTF for popular distros / older kernels.

Yes, it seems that I need to generate BTF for my 4.9 kernel somehow and pass it with ProgramOptions.

[tanshihaj]

It seems that latest (31bc0d7410572f6e03e3ed9da7c8c6f0d8df23c8) pahole from https://github.com/acmel/dwarves generates BTF from vmlinux for kernel 4.9 with command ./dwarves/build/pahole --btf_encode_detached vmlinux-4.9.253-....btf /boot/vmlinux-4.9.253-....