reproduce:
        # https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/commit/?id=a5af0b602e5ecb379fd2470669654a6abe7e97a2
        git remote add akpm-mm https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git
        git fetch --no-tags akpm-mm mm-unstable
        git checkout a5af0b602e5ecb379fd2470669654a6abe7e97a2
        # 1. reproduce by kismet
           # install kmax per https://github.com/paulgazz/kmax/blob/master/README.md
           kismet --linux-ksrc=linux --selectees CONFIG_CRASH_DUMP --selectors CONFIG_FA_DUMP -a=powerpc
        # 2. reproduce by make
           # save the config file to linux source tree
           cd linux
           make ARCH=powerpc olddefconfig