reproduce:
        # https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/commit/?id=2618dfca21ab2b38484908efbe94e5d17c7dee3b
        git remote add kees https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git
        git fetch --no-tags kees dev/v6.13-rc2/truncated-nonstring
        git checkout 2618dfca21ab2b38484908efbe94e5d17c7dee3b
        make W=1 O=/tmp/kselftest headers
        make W=1 O=/tmp/kselftest -C tools/testing/selftests
        make W=1 O=/tmp/kselftest -C tools/testing/selftests/bpf