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>
---
scripts/link-vmlinux.sh | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 3b342b0b0b38..66e7053aa907 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -233,6 +233,10 @@ gen_btf()
vmlinux_link ${1}
+ if [ "${pahole_ver}" -ge "118" ] && [ "${pahole_ver}" -le "121" ]; then
+ # pahole 1.18 through 1.21 can't handle zero-sized per-CPU vars
+ extra_paholeopt="${extra_paholeopt} --skip_encoding_btf_vars"
+ fi
if [ "${pahole_ver}" -ge "121" ]; then
extra_paholeopt="${extra_paholeopt} --btf_gen_floats"
fi
--
2.30.2
