reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/chao/linux.git/commit/?id=28a4fc03f837d64c67eeeba5ef226dbed4b369dc
        git remote add chao https://git.kernel.org/pub/scm/linux/kernel/git/chao/linux.git
        git fetch --no-tags chao bugfix/syzbot
        git checkout 28a4fc03f837d64c67eeeba5ef226dbed4b369dc
        # 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