Hi Vincent, FYI, the error/warning still remains. tree: https://android.googlesource.com/kernel/common android12-5.10-2021-09 head: cac628d5320f43641e9fb9285d972060b61ca2de commit: e19b8ce907a4ccc2f9dbeba218c50d1ff07fd321 [1944/10852] ANDROID: cpu/hotplug: add migration to paused_cpus config: x86_64-randconfig-r033-20210928 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project dc6e8dfdfe7efecfda318d43a06fae18b40eb498) 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 remote add android-common https://android.googlesource.com/kernel/common git fetch --no-tags android-common android12-5.10-2021-09 git checkout e19b8ce907a4ccc2f9dbeba218c50d1ff07fd321 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross 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 >>): int __pause_drain_rq(struct cpumask *cpus) ^ kernel/cpu.c:1098:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int __pause_drain_rq(struct cpumask *cpus) ^ static void __wait_drain_rq(struct cpumask *cpus) ^ kernel/cpu.c:1118:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __wait_drain_rq(struct cpumask *cpus) ^ static 2 warnings generated. vim +/__pause_drain_rq +1098 kernel/cpu.c 1097 1099 { 1100 unsigned int cpu; 1101 int err = 0; 1102 1103 /* 1104 * Disabling preemption avoids that one of the stopper, started from 1105 * sched_cpu_drain_rq(), blocks firing draining for the whole cpumask. 1106 */ 1107 preempt_disable(); 1108 for_each_cpu(cpu, cpus) { 1109 err = sched_cpu_drain_rq(cpu); 1110 if (err) 1111 break; 1112 } 1113 preempt_enable(); 1114 1115 return err; 1116 } 1117 1119 { 1120 unsigned int cpu; 1121 1122 for_each_cpu(cpu, cpus) 1123 sched_cpu_drain_rq_wait(cpu); 1124 } 1125 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org