reproduce (this is a W=1 build):
        git remote add drm-misc git://anongit.freedesktop.org/drm/drm-misc
        git fetch drm-misc drm-misc-next
        git checkout drm-misc/drm-misc-next
        b4 shazam https://lore.kernel.org/r/a18dcae310f74dcb9c6fc01d5bdc0568@AcuMS.aculab.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 arch/x86/mm/