[tip:smp/urgent 1/1] kernel/cpu.c:1353:2: error: implicit declaration of function 'cpu_up_down_serialize_trainwrecks'

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git smp/urgent
head:   64c71be97c02c3d3f24dea7c290912ad300538b9
commit: 64c71be97c02c3d3f24dea7c290912ad300538b9 [1/1] cpu/hotplug: Cure the cpusets trainwreck
config: mips-randconfig-r005-20210620 (attached as .config)
compiler: mips64-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
        # https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=64c71be97c02c3d3f24dea7c290912ad300538b9
        git remote add tip https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
        git fetch --no-tags tip smp/urgent
        git checkout 64c71be97c02c3d3f24dea7c290912ad300538b9
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=mips 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

   kernel/cpu.c: In function '_cpu_up':
>> kernel/cpu.c:1353:2: error: implicit declaration of function 'cpu_up_down_serialize_trainwrecks' [-Werror=implicit-function-declaration]
    1353 |  cpu_up_down_serialize_trainwrecks(tasks_frozen);
         |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/cpu_up_down_serialize_trainwrecks +1353 kernel/cpu.c

  1295	
  1296	/* Requires cpu_add_remove_lock to be held */
  1297	static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target)
  1298	{
  1299		struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
  1300		struct task_struct *idle;
  1301		int ret = 0;
  1302	
  1303		cpus_write_lock();
  1304	
  1305		if (!cpu_present(cpu)) {
  1306			ret = -EINVAL;
  1307			goto out;
  1308		}
  1309	
  1310		/*
  1311		 * The caller of cpu_up() might have raced with another
  1312		 * caller. Nothing to do.
  1313		 */
  1314		if (st->state >= target)
  1315			goto out;
  1316	
  1317		if (st->state == CPUHP_OFFLINE) {
  1318			/* Let it fail before we try to bring the cpu up */
  1319			idle = idle_thread_get(cpu);
  1320			if (IS_ERR(idle)) {
  1321				ret = PTR_ERR(idle);
  1322				goto out;
  1323			}
  1324		}
  1325	
  1326		cpuhp_tasks_frozen = tasks_frozen;
  1327	
  1328		cpuhp_set_state(st, target);
  1329		/*
  1330		 * If the current CPU state is in the range of the AP hotplug thread,
  1331		 * then we need to kick the thread once more.
  1332		 */
  1333		if (st->state > CPUHP_BRINGUP_CPU) {
  1334			ret = cpuhp_kick_ap_work(cpu);
  1335			/*
  1336			 * The AP side has done the error rollback already. Just
  1337			 * return the error code..
  1338			 */
  1339			if (ret)
  1340				goto out;
  1341		}
  1342	
  1343		/*
  1344		 * Try to reach the target state. We max out on the BP at
  1345		 * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is
  1346		 * responsible for bringing it up to the target state.
  1347		 */
  1348		target = min((int)target, CPUHP_BRINGUP_CPU);
  1349		ret = cpuhp_up_callbacks(cpu, st, target);
  1350	out:
  1351		cpus_write_unlock();
  1352		arch_smt_update();
> 1353		cpu_up_down_serialize_trainwrecks(tasks_frozen);
  1354		return ret;
  1355	}
  1356	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

Attachment: .config.gz
Description: application/gzip