tree: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git rcu/next head: 8e97ee7a3a2a6e583619a932a0404d7ae4302dcf commit: 589081348a37ec02d9b067aa08d4a771ae590e1e [61/65] rcu-tasks: Add RCU tasks to rcutorture writer stall output config: mips-lemote2f_defconfig (attached as .config) compiler: mips64el-linux-gcc (GCC) 5.5.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross git checkout 589081348a37ec02d9b067aa08d4a771ae590e1e # save the attached .config to linux build tree GCC_VERSION=5.5.0 make.cross ARCH=mips If you fix the issue, kindly add following tag Reported-by: kbuild test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): In file included from kernel/rcu/update.c:562:0: kernel/rcu/tasks.h: In function 'show_rcu_tasks_gp_kthreads': show_rcu_tasks_generic_gp_kthread(&rcu_tasks_rude, ""); ^ kernel/rcu/tasks.h:1000:37: note: each undeclared identifier is reported only once for each function it appears in vim +/rcu_tasks_rude +1000 kernel/rcu/tasks.h 996 997 void show_rcu_tasks_gp_kthreads(void) 998 { 999 show_rcu_tasks_generic_gp_kthread(&rcu_tasks, ""); 1001 show_rcu_tasks_trace_gp_kthread(); 1002 } 1003 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org