Re: Reading Pinned maps in eBPF Programs


Andrii Nakryiko
 

On Mon, Aug 31, 2020 at 12:03 PM Ian <icampbe14@gmail.com> wrote:

Interestingly enough adding just -g in my Makefile built the BPF programs and allowed the BTF section to be found and properly loaded. My BPF program was loaded and is running properly with my desired functionality. I am confused though as to why the -g flag fixed this problem. Which according to the clang man page:

-g Generate debug information.

Is BTF information considered debug information? Is that in general or in this case? Is the this unexpected behavior? Perhaps a bug of clangs non -g compiled binaries with BPF? It would seem to me that the BTF information should not be purged from a non -g binary. I am interested to hear your thought on this Andrii!
It's expected right now. BTF started out as purely debug information,
but got elevated into pretty much a mandatory thing for modern BPF
applications. We've talked about making .BTF emitted without -g, but
that hasn't happened in Clang yet (there are some technical
difficulties).

Again, thank you so much for your help. There is no way I would have figured that out on my own.

Ian

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