reproduce (this is a W=1 build):
        git remote add xen-tip https://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git
        git fetch xen-tip linux-next
        git checkout xen-tip/linux-next
        b4 shazam https://lore.kernel.org/r/20250404133459.16125-1-roger.pau@citrix.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