reproduce (this is a W=1 build):
        git checkout linus/master
        b4 shazam https://lore.kernel.org/r/tencent_816D842DE96C309554E8E2ED9ACC6078120A@qq.com
        # 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 fs/bcachefs/