tree: https://android.googlesource.com/kernel/common android-4.19-stable head: 95a98ff058c1e19c6a2538b490229dbe83386d59 commit: 4c3d3d24ddc40acc3204e1225a53eb95db2893e7 [17247/17251] ANDROID: GKI: kernel: tick-sched: Add an API for wakeup callbacks config: x86_64-randconfig-c024-20200720 (attached as .config) compiler: gcc-9 (Debian 9.3.0-14) 9.3.0 reproduce (this is a W=1 build): git checkout 4c3d3d24ddc40acc3204e1225a53eb95db2893e7 # save the attached .config to linux build tree make 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 errors (new ones prefixed by >>): kernel/time/tick-sched.c: In function 'register_tick_sched_wakeup_callback': 1409 | if (!wake_callback) | ^~~~~~~~~~~~~ kernel/time/tick-sched.c:1409:7: note: each undeclared identifier is reported only once for each function it appears in vim +/wake_callback +1409 kernel/time/tick-sched.c 1406 1407 void register_tick_sched_wakeup_callback(void (*cb)(void)) 1408 { 1410 wake_callback = cb; 1411 else 1412 pr_warn("tick-sched wake cb already exists; skipping.\n"); 1413 } 1414 EXPORT_SYMBOL_GPL(register_tick_sched_wakeup_callback); 1415 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org