reproduce (this is a W=1 build):
        git remote add usb https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
        git fetch usb usb-linus
        git checkout usb/usb-linus
        b4 shazam https://lore.kernel.org/r/20240116-ml-topic-u9p-v10-2-a85fdeac2c52@pengutronix.de
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash net/9p/