tree: https://github.com/zen-kernel/zen-kernel 5.9/muqss head: 8969d3bb632504cea984c900b71176e2d4c7997e commit: 49e82d66c704858ba77947984535811593d6dacb [1/20] MultiQueue Skiplist Scheduler v0.204 config: x86_64-randconfig-m001-20201117 (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 reproduce (this is a W=1 build): # https://github.com/zen-kernel/zen-kernel/commit/49e82d66c704858ba77947984... git remote add zen-kernel-zen-kernel https://github.com/zen-kernel/zen-kernel git fetch --no-tags zen-kernel-zen-kernel 5.9/muqss git checkout 49e82d66c704858ba77947984535811593d6dacb # save the attached .config to linux build tree make W=1 ARCH=x86_64 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 >>): kernel/sched/MuQSS.c:639:6: warning: no previous prototype for 'resched_task' [-Wmissing-prototypes] 639 | void resched_task(struct task_struct *p) | ^~~~~~~~~~~~ kernel/sched/MuQSS.c:2386:5: warning: no previous prototype for 'sysctl_schedstats' [-Wmissing-prototypes] 2386 | int sysctl_schedstats(struct ctl_table *table, int write, void *buffer, | ^~~~~~~~~~~~~~~~~ kernel/sched/MuQSS.c:3076:15: warning: no previous prototype for 'nr_active' [-Wmissing-prototypes] 3076 | unsigned long nr_active(void) | ^~~~~~~~~ 4407 | asmlinkage __visible void __sched schedule_user(void) | ^~~~~~~~~~~~~ kernel/sched/MuQSS.c:6234:6: warning: no previous prototype for 'resched_cpu' [-Wmissing-prototypes] 6234 | void resched_cpu(int cpu) | ^~~~~~~~~~~ kernel/sched/MuQSS.c:7697:6: warning: no previous prototype for 'init_idle_bootup_task' [-Wmissing-prototypes] 7697 | void init_idle_bootup_task(struct task_struct *idle) | ^~~~~~~~~~~~~~~~~~~~~ vim +/schedule_user +4407 kernel/sched/MuQSS.c 4405 4406 #ifdef CONFIG_CONTEXT_TRACKING 4408 { 4409 /* 4410 * If we come here after a random call to set_need_resched(), 4411 * or we have been woken up remotely but the IPI has not yet arrived, 4412 * we haven't yet exited the RCU idle mode. Do it here manually until 4413 * we find a better solution. 4414 * 4415 * NB: There are buggy callers of this function. Ideally we 4416 * should warn if prev_state != IN_USER, but that will trigger 4417 * too frequently to make sense yet. 4418 */ 4419 enum ctx_state prev_state = exception_enter(); 4420 schedule(); 4421 exception_exit(prev_state); 4422 } 4423 #endif 4424 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org