reproduce (this is a W=1 build):
        git remote add tj-cgroup https://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git
        git fetch tj-cgroup for-next
        git checkout tj-cgroup/for-next
        b4 shazam https://lore.kernel.org/r/20251223102124.738818-4-ptikhomirov@virtuozzo.com

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/ kernel/