tree: https://github.com/zen-kernel/zen-kernel 5.11/futex2 head: ea9a7956b5f6f44f3ee70d82542c64fcb7c86c5e commit: ea9a7956b5f6f44f3ee70d82542c64fcb7c86c5e [13/13] futex2: Add sysfs entry for syscall numbers config: xtensa-randconfig-r012-20210217 (attached as .config) compiler: xtensa-linux-gcc (GCC) 9.3.0 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://github.com/zen-kernel/zen-kernel/commit/ea9a7956b5f6f44f3ee70d825... git remote add zen-kernel-zen-kernel https://github.com/zen-kernel/zen-kernel git fetch --no-tags zen-kernel-zen-kernel 5.11/futex2 git checkout ea9a7956b5f6f44f3ee70d82542c64fcb7c86c5e # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=xtensa 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 >>): kernel/futex2.c: In function 'wait_show': 1226 | return sprintf(buf, "%u\n", __NR_futex_wait); | ^~~~~~~~~~~~~~~ | __futex_wait kernel/futex2.c:1226:30: note: each undeclared identifier is reported only once for each function it appears in kernel/futex2.c: In function 'wake_show': 1234 | return sprintf(buf, "%u\n", __NR_futex_wake); | ^~~~~~~~~~~~~~~ | sys_futex_wake kernel/futex2.c: In function 'waitv_show': 1242 | return sprintf(buf, "%u\n", __NR_futex_waitv); | ^~~~~~~~~~~~~~~~ | __futex_wait kernel/futex2.c:1244:1: error: control reaches end of non-void function [-Werror=return-type] 1244 | } | ^ kernel/futex2.c: In function 'wake_show': kernel/futex2.c:1236:1: error: control reaches end of non-void function [-Werror=return-type] 1236 | } | ^ kernel/futex2.c: In function 'wait_show': kernel/futex2.c:1228:1: error: control reaches end of non-void function [-Werror=return-type] 1228 | } | ^ cc1: some warnings being treated as errors vim +1226 kernel/futex2.c 1222 1223 static ssize_t wait_show(struct kobject *kobj, struct kobj_attribute *attr, 1224 char *buf) 1225 { 1227 1228 } 1229 static struct kobj_attribute futex2_wait_attr = __ATTR_RO(wait); 1230 1231 static ssize_t wake_show(struct kobject *kobj, struct kobj_attribute *attr, 1232 char *buf) 1233 { 1235 1236 } 1237 static struct kobj_attribute futex2_wake_attr = __ATTR_RO(wake); 1238 1239 static ssize_t waitv_show(struct kobject *kobj, struct kobj_attribute *attr, 1240 char *buf) 1241 { 1243 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org