Hi Hsin-Yi, Thank you for the patch! Yet something to improve: [auto build test ERROR on next-20200110] [also build test ERROR on v5.5-rc6] [cannot apply to arm64/for-next/core arm/for-next ia64/next hp-parisc/for-next powerpc/next s390/features sparc/master tip/x86/core linus/master sparc-next/master v5.5-rc6 v5.5-rc5 v5.5-rc4] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Hsin-Yi-Wang/reboot-support-hotplug-CPUs-before-reboot/20200114-143340 base: 6c09d7dbb7d366122d0218bc7487e0a1e6cca6ed config: powerpc-rhel-kconfig (attached as .config) compiler: powerpc64le-linux-gcc (GCC) 7.5.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree GCC_VERSION=7.5.0 make.cross ARCH=powerpc If you fix the issue, kindly add following tag Reported-by: kbuild test robot All errors (new ones prefixed by >>): >> kernel/cpu.c:1286:6: error: redefinition of 'enable_nonboot_cpus' void enable_nonboot_cpus(void) ^~~~~~~~~~~~~~~~~~~ In file included from kernel/cpu.c:16:0: include/linux/cpu.h:167:20: note: previous definition of 'enable_nonboot_cpus' was here static inline void enable_nonboot_cpus(void) {} ^~~~~~~~~~~~~~~~~~~ vim +/enable_nonboot_cpus +1286 kernel/cpu.c d0af9eed5aa91b Suresh Siddha 2009-08-19 1285 71cf5aeeb8e215 Mathias Krause 2015-07-19 @1286 void enable_nonboot_cpus(void) e3920fb42c8ddf Rafael J. Wysocki 2006-09-25 1287 { e3920fb42c8ddf Rafael J. Wysocki 2006-09-25 1288 int cpu, error; e3920fb42c8ddf Rafael J. Wysocki 2006-09-25 1289 e3920fb42c8ddf Rafael J. Wysocki 2006-09-25 1290 /* Allow everyone to use the CPU hotplug again */ d221938c049f48 Gautham R Shenoy 2008-01-25 1291 cpu_maps_update_begin(); 01b41159066531 Lianwei Wang 2016-06-09 1292 __cpu_hotplug_enable(); e0b582ec56f1a1 Rusty Russell 2009-01-01 1293 if (cpumask_empty(frozen_cpus)) 1d64b9cb1dc2a7 Rafael J. Wysocki 2007-04-01 1294 goto out; e3920fb42c8ddf Rafael J. Wysocki 2006-09-25 1295 84117da5b79ffb Fabian Frederick 2014-06-04 1296 pr_info("Enabling non-boot CPUs ...\n"); d0af9eed5aa91b Suresh Siddha 2009-08-19 1297 d0af9eed5aa91b Suresh Siddha 2009-08-19 1298 arch_enable_nonboot_cpus_begin(); d0af9eed5aa91b Suresh Siddha 2009-08-19 1299 e0b582ec56f1a1 Rusty Russell 2009-01-01 1300 for_each_cpu(cpu, frozen_cpus) { bb3632c6101b2f Todd E Brandt 2014-06-06 1301 trace_suspend_resume(TPS("CPU_ON"), cpu, true); af1f40457da6f7 Thomas Gleixner 2016-02-26 1302 error = _cpu_up(cpu, 1, CPUHP_ONLINE); bb3632c6101b2f Todd E Brandt 2014-06-06 1303 trace_suspend_resume(TPS("CPU_ON"), cpu, false); e3920fb42c8ddf Rafael J. Wysocki 2006-09-25 1304 if (!error) { 84117da5b79ffb Fabian Frederick 2014-06-04 1305 pr_info("CPU%d is up\n", cpu); e3920fb42c8ddf Rafael J. Wysocki 2006-09-25 1306 continue; e3920fb42c8ddf Rafael J. Wysocki 2006-09-25 1307 } 84117da5b79ffb Fabian Frederick 2014-06-04 1308 pr_warn("Error taking CPU%d up: %d\n", cpu, error); e3920fb42c8ddf Rafael J. Wysocki 2006-09-25 1309 } d0af9eed5aa91b Suresh Siddha 2009-08-19 1310 d0af9eed5aa91b Suresh Siddha 2009-08-19 1311 arch_enable_nonboot_cpus_end(); d0af9eed5aa91b Suresh Siddha 2009-08-19 1312 e0b582ec56f1a1 Rusty Russell 2009-01-01 1313 cpumask_clear(frozen_cpus); 1d64b9cb1dc2a7 Rafael J. Wysocki 2007-04-01 1314 out: d221938c049f48 Gautham R Shenoy 2008-01-25 1315 cpu_maps_update_done(); ^1da177e4c3f41 Linus Torvalds 2005-04-16 1316 } e0b582ec56f1a1 Rusty Russell 2009-01-01 1317 :::::: The code at line 1286 was first introduced by commit :::::: 71cf5aeeb8e2154efda5f40be50c925f15057755 kernel, cpu: Remove bogus __ref annotations :::::: TO: Mathias Krause :::::: CC: Greg Kroah-Hartman --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org Intel Corporation