reproduce (this is a W=1 build):
        git remote add bpf-next https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git
        git fetch bpf-next master
        git checkout bpf-next/master
        b4 shazam https://lore.kernel.org/r/AM6PR03MB5848C2304B17658423B4B81D99932@AM6PR03MB5848.eurprd03.prod.outlook.com
        # 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 kernel/bpf/