Re: Questions about the state of some BTF features

[Alan Maguire <alan.maguire@oracle.com>]

On 25/10/2024 17:09, Alexei Starovoitov wrote:
> On Thu, Oct 24, 2024 at 4:26 PM Andrii Nakryiko
> <andrii.nakryiko@gmail.com> wrote:
>>
>>>
>>> The good news is that already happens, provided you have the updated
>>> pahole to handle distilled base generation. After building selftests I see
>>>
>>> $ objdump -h bpf_testmod.ko |grep BTF
>>>   7 .BTF_ids      000001c8  0000000000000000  0000000000000000  00002c50
>>>  2**0
>>>  50 .BTF          000036f4  0000000000000000  0000000000000000  0006e048
>>>  2**0
>>>  51 .BTF.base     000004cc  0000000000000000  0000000000000000  0007173c
>>>  2**0
>>>
>>
>> Indeed, after updating to the latest pahole master now I get
>> .BTF.base, very nice.
> 
> I pulled the latest pahole, rebuilt everything,
> but still cannot get it to generate BTF.base.
> 
> Any special trick needed?

Hmm, should just work for bpf_testmod.ko as long as "pahole
--supported_btf_features" reports "distilled_base" among the set of
features. scripts/Makefile.btf should add that feature if KBUILD_EXTMOD
is set, as it should be in the case of building bpf_testmod.ko. I'll
double-check at my end with latest bpf-next, but it was working
yesterday for me.

Alan