tree: https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git 20211118-sysctl-cleanups-set-04-v2 head: 3110d41a56792588bd2f64621080948b0fceb6ab commit: f413b2178aaff38d62d6c905d716d218388537a2 [8/36] aio: move aio sysctl to aio.c config: nds32-allnoconfig (attached as .config) compiler: nds32le-linux-gcc (GCC) 11.2.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git/com... git remote add mcgrof-next https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git git fetch --no-tags mcgrof-next 20211118-sysctl-cleanups-set-04-v2 git checkout f413b2178aaff38d62d6c905d716d218388537a2 # save the attached .config to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=nds32 SHELL=/bin/bash If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): fs/aio.c: In function 'aio_sysctl_init': 246 | register_sysctl_init("fs", aio_sysctls, "aio_sysctls"); | ^ In file included from include/linux/key.h:17, from include/linux/cred.h:13, from include/linux/sched/signal.h:10, from include/linux/rcuwait.h:6, from include/linux/percpu-rwsem.h:7, from include/linux/fs.h:33, from include/uapi/linux/aio_abi.h:31, from fs/aio.c:18: include/linux/sysctl.h:210: note: macro "register_sysctl_init" defined here 210 | #define register_sysctl_init(path, table) __register_sysctl_init(path, table, #table) | 246 | register_sysctl_init("fs", aio_sysctls, "aio_sysctls"); | ^~~~~~~~~~~~~~~~~~~~ | register_sysctl_paths fs/aio.c:246:9: note: each undeclared identifier is reported only once for each function it appears in At top level: fs/aio.c:226:25: warning: 'aio_sysctls' defined but not used [-Wunused-variable] 226 | static struct ctl_table aio_sysctls[] = { | ^~~~~~~~~~~ vim +/register_sysctl_init +246 fs/aio.c 243 244 static void __init aio_sysctl_init(void) 245 { 247 } 248 #else 249 #define aio_sysctl_init() do { } while (0) 250 #endif 251 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org