tree: https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git sched/core head: e337f389dc4d3748ba4342bd2d1c2133346b8691 commit: 92318ca36a5876d444849ea850534488e843f077 [2/4] sched/hotplug: Ensure only per-cpu kthreads run during hotplug config: alpha-randconfig-r036-20200913 (attached as .config) compiler: alpha-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 git checkout 92318ca36a5876d444849ea850534488e843f077 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=alpha 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/sched/core.c:2380:6: warning: no previous prototype for 'sched_set_stop_task' [-Wmissing-prototypes] 2380 | void sched_set_stop_task(int cpu, struct task_struct *stop) | ^~~~~~~~~~~~~~~~~~~ kernel/sched/core.c: In function 'schedule_tail': kernel/sched/core.c:3742:13: warning: variable 'rq' set but not used [-Wunused-but-set-variable] 3742 | struct rq *rq; | ^~ kernel/sched/core.c: In function 'sched_cpu_activate': 7018 | balance_push_set(cpu, false); | ^~~~~~~~~~~~~~~~ | balance_push cc1: some warnings being treated as errors # https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?... git remote add peterz-queue https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git git fetch --no-tags peterz-queue sched/core git checkout 92318ca36a5876d444849ea850534488e843f077 vim +7018 kernel/sched/core.c 7012 7013 int sched_cpu_activate(unsigned int cpu) 7014 { 7015 struct rq *rq = cpu_rq(cpu); 7016 struct rq_flags rf; 7017 7019 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org