Re: [RFC PATCH 0/9] pahole: shared ELF and faster reproducible BTF encoding

[Jiri Olsa <olsajiri@gmail.com>]

On Thu, Nov 28, 2024 at 01:23:44AM +0000, Ihor Solodrai wrote:

SNIP

> Test results for this patch series:
> 
>   1: Validation of BTF encoding of functions; this may take some time: Ok
>   2: Default BTF on a system without BTF: Ok
>   3: Flexible arrays accounting: WARNING: still unsuported BTF_KIND_DECL_TAG(bpf_fastcall) for bpf_cast_to_kern_ctx already with attribute (bpf_kfunc), ignoring
> WARNING: still unsuported BTF_KIND_DECL_TAG(bpf_fastcall) for bpf_rdonly_cast already with attribute (bpf_kfunc), ignoring
> pahole: type 'nft_pipapo_elem' not found
> pahole: type 'ip6t_standard' not found
> pahole: type 'ip6t_error' not found
> pahole: type 'nft_rbtree_elem' not found
> pahole: type 'nft_rule_dp_last' not found
> pahole: type 'nft_bitmap_elem' not found
> pahole: type 'fuse_direntplus' not found
> pahole: type 'ipt_standard' not found
> pahole: type 'ipt_error' not found
> pahole: type 'tls_rec' not found
> pahole: type 'nft_rhash_elem' not found
> pahole: type 'nft_hash_elem' not found
> Ok
>   4: Pretty printing of files using DWARF type information: Ok
>   5: Parallel reproducible DWARF Loading/Serial BTF encoding: Ok

hi,
when trying selftests with this change, I'm getting wrong .BTF
on bpf selftest bpf_testmod.ko module

$ bpftool btf dump file ./bpf_testmod.ko
Error: failed to load BTF from ./bpf_testmod.ko: Invalid argument

jirka

> 
> 
> [1]: https://lore.kernel.org/dwarves/20241016001025.857970-1-ihor.solodrai@pm.me/
> [2]: https://github.com/theihor/dwarves/pull/3
> [3]: https://lore.kernel.org/dwarves/8678ce40-3ce2-4ece-985b-a40427386d57@oracle.com/
> [4]: https://github.com/acmel/dwarves/compare/master...alan-maguire:dwarves:elf-prep
> [5]: https://github.com/theihor/dwarves/pull/8
> [6]: https://gist.github.com/theihor/f000ce89427828e61fdaa567b332649b
> [7]: https://github.com/theihor/dwarves/pull/8/commits/a7bc67d79d90f98776c6dc5fdaf9f088eb09909d
> 
> 
> Alan Maguire (3):
>   btf_encoder: simplify function encoding
>   btf_encoder: store,use section-relative addresses in ELF function
>     representation
>   btf_encoder: separate elf function, saved function representations
> 
> Ihor Solodrai (6):
>   dwarf_loader: introduce pre_load_module hook to conf_load
>   btf_encoder: introduce elf_functions struct type
>   btf_encoder: collect elf_functions in btf_encoder__pre_load_module
>   btf_encoder: switch to shared elf_functions table
>   btf_encoder: introduce btf_encoding_context
>   pahole: faster reproducible BTF encoding
> 
>  btf_encoder.c  | 661 ++++++++++++++++++++++++++++++-------------------
>  btf_encoder.h  |   6 +
>  dwarf_loader.c |  18 +-
>  dwarves.c      |  47 ++--
>  dwarves.h      |  16 +-
>  pahole.c       | 265 +++++++++-----------
>  6 files changed, 567 insertions(+), 446 deletions(-)
> 
> -- 
> 2.47.0
> 
>