Re: [PATCH bpf v2] bpf: Add config for skipping BTF enum64s

[Jiri Olsa <olsajiri@gmail.com>]

On Sun, Aug 28, 2022 at 08:33:17PM -0300, Martin Rodriguez Reboredo wrote:
> After the release of pahole 1.24 some people in the dwarves mailing list
> notified issues related to building the kernel with the BTF_DEBUG_INFO
> option toggled. They seem to be happenning due to the kernel and
> resolve_btfids interpreting btf types erroneously. In the dwarves list
> I've proposed a change to the scripts that I've written while testing
> the Rust kernel, it simply passes the --skip_encoding_btf_enum64 to
> pahole if it has version 1.24.
> 
> v1 -> v2:
> - Switch to off by default and remove the config option.
> - Send it to stable instead.

hi,
we have change that needs to go to stable kernels but does not have the
equivalent fix in Linus tree

what would be the best way to submit it?

the issue is that new 'pahole' will generate BTF data that are not supported
by older kernels, so we need to add --skip_encoding_btf_enum64 option to
stable kernel's scripts/pahole-flags.sh to generate proper BTF data

we got complains that after upgrading to latest pahole the stable kernel
compilation fails

thanks,
jirka


> 
> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
> ---
>  scripts/pahole-flags.sh | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/scripts/pahole-flags.sh b/scripts/pahole-flags.sh
> index 0d99ef17e4a5..0a48fd86bc68 100755
> --- a/scripts/pahole-flags.sh
> +++ b/scripts/pahole-flags.sh
> @@ -19,5 +19,8 @@ fi
>  if [ "${pahole_ver}" -ge "122" ]; then
>  	extra_paholeopt="${extra_paholeopt} -j"
>  fi
> +if [ "${pahole_ver}" -ge "124" ]; then
> +	extra_paholeopt="${extra_paholeopt} --skip_encoding_btf_enum64"
> +fi
>  
>  echo ${extra_paholeopt}
> -- 
> 2.37.2
>