reproduce (this is a W=1 build):
        git remote add net https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git
        git fetch net main
        git checkout net/main
        b4 shazam https://lore.kernel.org/r/20231011003313.105315-1-kuba@kernel.org
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=um SUBARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=um SUBARCH=i386 SHELL=/bin/bash