Re: [PATCH] kbuild: skip per-CPU BTF generation for pahole v1.18-v1.21

[Mel Gorman]

On Sat, May 29, 2021 at 05:25:36PM -0700, Andrii Nakryiko wrote:
> Commit "mm/page_alloc: convert per-cpu list protection to local_lock"
> introduced a zero-sized per-CPU variable, which causes pahole to generate
> invalid BTF. Only pahole versions 1.18 through 1.21 are impacted, as before
> 1.18 pahole doesn't know anything about per-CPU variables, and 1.22 contains
> the proper fix for the issue.
> 
> Luckily, pahole 1.18 got --skip_encoding_btf_vars option disabling BTF
> generation for per-CPU variables in anticipation of some unanticipated
> problems. So use this escape hatch to disable per-CPU var BTF info on those
> problematic pahole versions. Users relying on availability of per-CPU var BTFs
> would need to upgrade to pahole 1.22+, but everyone won't notice any
> regressions.
> 
> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: Hao Luo <haoluo@xxxxxxxxxx>
> Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>

Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>

-- 
Mel Gorman
SUSE Labs