reproduce (this is a W=1 build):
        git remote add cxl https://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl.git
        git fetch cxl next
        git checkout cxl/next
        b4 shazam https://lore.kernel.org/r/20240618165310.877974-1-ruansy.fnst@fujitsu.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