Re: [PATCH 5.10] kbuild: fix BTF build with pahole 1.24

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Thu, Oct 27, 2022 at 02:58:47PM +0200, Jiri Olsa wrote:
> On Thu, Oct 27, 2022 at 09:01:58PM +0900, Dominique Martinet wrote:
> > pahole 1.24 broke builds on kernel <6.0 which do not have the
> > new BTF_KIND_ENUM64 BTF tag.
> > The 5.15 branch fixed this in commit b775fbf532dc01ae53a6fc56168fd30cb4b0c658
> > ("kbuild: Add skip_encoding_btf_enum64 option to pahole"), which
> > we cannot use directly for 5.10 because 5.10 does not have the
> > pahole-flags.sh script, itself introduced in upstream commit
> > 0baced0e0938f2895ceba54038eaf15ed91032e7 ("kbuild: Unify options
> > for BTF generation for vmlinux and modules")
> > 
> > that last commit is difficult to backport as 5.10 does not have BTF
> > for modules support: work around the problem by just copying the
> > pahole-flags.sh script and calling it directly in link-vmlinux.sh,
> > which is hopefully acceptable as the flags are not shared in this tree.
> > 
> > Note that compared to 5.15 the flags script does not have
> > --btf_gen_floats as linux 5.10 did not have that BTF tag yet;
> > but any new flag added to 5.15 will not be able to be added to 5.10 in
> > an identical way for any future breakage.
> > 
> > Cc: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
> > Cc: Jiri Olsa <jolsa@kernel.org>
> > CC: Andrii Nakryiko <andrii@kernel.org>
> > Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
> 
> hi,
> I sent this backport just recently:
>   https://lore.kernel.org/bpf/Y1lkASXgeW0jfP8o@kroah.com/T/#t
> 
> it's split into several patches, hopefuly fixing the issue for you

Yes, this should be resolved in the next 5.10.y release.

thanks,

greg k-h