Re: [PATCH dwarves v4 0/6] btf_encoder: emit type tags for bpf_arena pointers

Alan Maguire
2025-03-20T20:35:03Z

On 20/03/2025 16:32, Ihor Solodrai wrote:
> On 2/28/25 11:46 AM, Ihor Solodrai wrote:
>> This patch series implements emitting appropriate BTF type tags for
>> argument and return types of kfuncs marked with KF_ARENA_* flags.
>>
>> For additional context see the description of BPF patch
>> "bpf: define KF_ARENA_* flags for bpf_arena kfuncs" [1].
>>
>> The feature depends on recent changes in libbpf [2].
>>
>> [1] https://lore.kernel.org/bpf/20250206003148.2308659-1-ihor.solodrai@linux.dev/
>> [2] https://lore.kernel.org/bpf/20250130201239.1429648-1-ihor.solodrai@linux.dev/
>>
>> v3->v4:
>> * Add a patch (#2) replacing compile-time libbpf version checks with
>> runtime checks for symbol availablility
>> * Add a patch (#3) bumping libbpf submodule commit to latest master
>> * Modify "btf_encoder: emit type tags for bpf_arena pointers"
>> (#2->#4) to not use compile time libbpf version checks
>>
>> v2->v3:
>> * Nits in patch #1
>>
>> v1->v2:
>> * Rewrite patch #1 refactoring btf_encoder__tag_kfuncs(): now the
>> post-processing step is removed entirely, and kfuncs are tagged in
>> btf_encoder__add_func().
>> * Nits and renames in patch #2
>> * Add patch #4 editing man pages
>>
>> v2: https://lore.kernel.org/dwarves/20250212201552.1431219-1-ihor.solodrai@linux.dev/
>> v1: https://lore.kernel.org/dwarves/20250207021442.155703-1-ihor.solodrai@linux.dev/
>>
>> Ihor Solodrai (6):
>> btf_encoder: refactor btf_encoder__tag_kfuncs()
>> btf_encoder: use __weak declarations of version-dependent libbpf API
>> pahole: sync with libbpf mainline
>> btf_encoder: emit type tags for bpf_arena pointers
>> pahole: introduce --btf_feature=attributes
>> man-pages: describe attributes and remove reproducible_build
>
> Hi Alan, Arnaldo.
>
> This series hasn't received any comments in a while.
> Do you plan to review/land this?
>

Yep, thanks for the reminder; I hit a wall last time I looked a this
when testing with a shared library libbpf versus embedded but I can get
around that now so I should have the testing done for both modes tomorrow.

Alan

> Thanks.
>
>>
>> btf_encoder.c | 328 ++++++++++++++++++++++-----------------------
>> dwarves.h | 13 +-
>> lib/bpf | 2 +-
>> man-pages/pahole.1 | 7 +-
>> pahole.c | 11 +-
>> 5 files changed, 188 insertions(+), 173 deletions(-)
>>