tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 8ab774587903771821b59471cc723bba6d893942 commit: b027789e5e50494c2325cc70c8642e7fd6059479 sched/fair: Prevent dead task groups from regaining cfs_rq's date: 5 days ago config: arm-randconfig-r031-20211116 (attached as .config) compiler: arm-linux-gnueabi-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/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout b027789e5e50494c2325cc70c8642e7fd6059479 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=arm If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): 257 | void unregister_rt_sched_group(struct task_group *tg) { } | ^~~~~~~~~~~~~~~~~~~~~~~~~ kernel/sched/rt.c:259:6: warning: no previous prototype for 'free_rt_sched_group' [-Wmissing-prototypes] 259 | void free_rt_sched_group(struct task_group *tg) { } | ^~~~~~~~~~~~~~~~~~~ kernel/sched/rt.c:261:5: warning: no previous prototype for 'alloc_rt_sched_group' [-Wmissing-prototypes] 261 | int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent) | ^~~~~~~~~~~~~~~~~~~~ kernel/sched/rt.c:675:6: warning: no previous prototype for 'sched_rt_bandwidth_account' [-Wmissing-prototypes] 675 | bool sched_rt_bandwidth_account(struct rt_rq *rt_rq) | ^~~~~~~~~~~~~~~~~~~~~~~~~~ vim +/unregister_rt_sched_group +257 kernel/sched/rt.c 256 258 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org