Hi Baisong, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: f0c4d9fc9cc9462659728d168387191387e903cc commit: 28f152cd0926596e69d412467b11b6fe6fe4e864 sched/rt: fix build error when CONFIG_SYSCTL is disable date: 7 months ago config: x86_64-buildonly-randconfig-r002-20221107 compiler: gcc-11 (Debian 11.3.0-8) 11.3.0 reproduce (this is a W=1 build): # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=28f152cd0926596e69d412467b11b6fe6fe4e864 git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 28f152cd0926596e69d412467b11b6fe6fe4e864 # save the config file mkdir build_dir && cp config build_dir/.config make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash kernel/ If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot All warnings (new ones prefixed by >>): In file included from kernel/sched/build_policy.c:43: kernel/sched/rt.c:309:6: warning: no previous prototype for 'unregister_rt_sched_group' [-Wmissing-prototypes] 309 | void unregister_rt_sched_group(struct task_group *tg) { } | ^~~~~~~~~~~~~~~~~~~~~~~~~ kernel/sched/rt.c:311:6: warning: no previous prototype for 'free_rt_sched_group' [-Wmissing-prototypes] 311 | void free_rt_sched_group(struct task_group *tg) { } | ^~~~~~~~~~~~~~~~~~~ kernel/sched/rt.c:313:5: warning: no previous prototype for 'alloc_rt_sched_group' [-Wmissing-prototypes] 313 | int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent) | ^~~~~~~~~~~~~~~~~~~~ kernel/sched/rt.c:716:6: warning: no previous prototype for 'sched_rt_bandwidth_account' [-Wmissing-prototypes] 716 | bool sched_rt_bandwidth_account(struct rt_rq *rt_rq) | ^~~~~~~~~~~~~~~~~~~~~~~~~~ >> kernel/sched/rt.c:9:18: warning: 'max_rt_runtime' defined but not used [-Wunused-const-variable=] 9 | static const u64 max_rt_runtime = MAX_BW; | ^~~~~~~~~~~~~~ vim +/max_rt_runtime +9 kernel/sched/rt.c d505b8af58912a Huaixin Chang 2020-04-25 @9 static const u64 max_rt_runtime = MAX_BW; ce0dbbbb30aee6 Clark Williams 2013-02-07 10 :::::: The code at line 9 was first introduced by commit :::::: d505b8af58912ae1e1a211fabc9995b19bd40828 sched: Defend cfs and rt bandwidth quota against overflow :::::: TO: Huaixin Chang :::::: CC: Peter Zijlstra -- 0-DAY CI Kernel Test Service https://01.org/lkp