tree: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next-test head: 0a2900256840208c4a4248ff5900ae57990d55dc commit: 7f24f76bc606cbae1b56a8a445a5353594c3cf18 [33/34] powerpc/smp: Move ppc_md.cpu_die() to smp_ops.cpu_offline_self() config: powerpc-randconfig-r024-20200811 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 4f2ad15db535873dda9bfe248a2771023b64a43c) 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 # install powerpc cross compiling tool for clang build # apt-get install binutils-powerpc-linux-gnu git checkout 7f24f76bc606cbae1b56a8a445a5353594c3cf18 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc 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 >>): arch/powerpc/platforms/powermac/smp.c:419:13: warning: no previous prototype for function 'smp_psurge_take_timebase' [-Wmissing-prototypes] void __init smp_psurge_take_timebase(void) ^ arch/powerpc/platforms/powermac/smp.c:419:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __init smp_psurge_take_timebase(void) ^ static arch/powerpc/platforms/powermac/smp.c:435:13: warning: no previous prototype for function 'smp_psurge_give_timebase' [-Wmissing-prototypes] void __init smp_psurge_give_timebase(void) ^ arch/powerpc/platforms/powermac/smp.c:435:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __init smp_psurge_give_timebase(void) ^ static low_cpu_offline_self(); ^ arch/powerpc/platforms/powermac/smp.c:933:2: note: did you mean 'pmac_cpu_offline_self'? arch/powerpc/platforms/powermac/smp.c:923:13: note: 'pmac_cpu_offline_self' declared here static void pmac_cpu_offline_self(void) ^ 2 warnings and 1 error generated. vim +/low_cpu_offline_self +933 arch/powerpc/platforms/powermac/smp.c 922 923 static void pmac_cpu_offline_self(void) 924 { 925 int cpu = smp_processor_id(); 926 927 local_irq_disable(); 928 idle_task_exit(); 929 pr_debug("CPU%d offline\n", cpu); 930 generic_set_cpu_dead(cpu); 931 smp_wmb(); 932 mb(); 934 } 935 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org