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 <redacted>
Cc: Arnaldo Carvalho de Melo <redacted>
Cc: Hao Luo <redacted>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

Acked-by: Mel Gorman <redacted>

-- 
Mel Gorman
SUSE Labs