reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git/commit/?id=f64d5d0ca0ec641579cbf42a9d3cdd33b75db717
        git remote add jolsa-perf https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
        git fetch --no-tags jolsa-perf bpf/optimized_usdt_13
        git checkout f64d5d0ca0ec641579cbf42a9d3cdd33b75db717
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash arch/x86/kernel/