scripts: Require pahole v1.16 when generating BTF

bpf_iter requires the kernel BTF to be generated with
pahole >= 1.16, since otherwise the function definitions
that the iterator attaches to are not included.
This failure mode is indistiguishable from trying to attach
to an iterator that really doesn't exist.

Since it's really easy to miss this requirement, bump the
pahole version check used at build time to at least 1.16.

Fixes: c73cf96a66fd ("bpf: Allow loading of a bpf_iter program")
Suggested-by: Ivan Babrou <ivan@cloudflare.com>
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200608094257.47366-1-lmb@cloudflare.com

diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 3adef49250af979b22e3180ae05a8adb382a29b6..a37875904ca680853e6228aabfab16a9d8806606 100755 (executable)
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -143,8 +143,8 @@ gen_btf()
        fi
 
        pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
-       if [ "${pahole_ver}" -lt "113" ]; then
-               echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.13"
+       if [ "${pahole_ver}" -lt "116" ]; then
+               echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.16"
                return 1
        fi