reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/commit/?id=ef341fb241454b950e310efdd75763462a25d9fc
        git remote add kees https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git
        git fetch --no-tags kees devel/overflow/enable-unsigned-sanitizer
        git checkout ef341fb241454b950e310efdd75763462a25d9fc
        # 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