tree: https://git.kernel.org/pub/scm/linux/kernel/git/sashal/linux-stable.git queue-5.4 head: d2c5af89e80c5b71f1da59879464a930947306a2 commit: 3c62d9df8c0139b34bca94fb340c95c03d3158d3 [130/132] rcu/nocb: Trigger self-IPI on late deferred wake up before user resume config: x86_64-randconfig-a003-20210318 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 436c6c9c20cc522c92a923440a5fc509c342a7db) 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 x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/sashal/linux-stable.git/c... git remote add sashal-linux-stable https://git.kernel.org/pub/scm/linux/kernel/git/sashal/linux-stable.git git fetch --no-tags sashal-linux-stable queue-5.4 git checkout 3c62d9df8c0139b34bca94fb340c95c03d3158d3 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross 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/rcu/tree.c:191:15: warning: no previous prototype for function 'rcu_rnp_online_cpus' [-Wmissing-prototypes] unsigned long rcu_rnp_online_cpus(struct rcu_node *rnp) ^ kernel/rcu/tree.c:191:1: note: declare 'static' if the function is not intended to be used outside of this translation unit unsigned long rcu_rnp_online_cpus(struct rcu_node *rnp) ^ static kernel/rcu/tree.c:297:6: warning: no previous prototype for function 'rcu_dynticks_curr_cpu_in_eqs' [-Wmissing-prototypes] bool rcu_dynticks_curr_cpu_in_eqs(void) ^ kernel/rcu/tree.c:297:1: note: declare 'static' if the function is not intended to be used outside of this translation unit bool rcu_dynticks_curr_cpu_in_eqs(void) ^ static IRQ_WORK_INIT(late_wakeup_func); ^ static DEFINE_PER_CPU(struct irq_work, late_wakeup_work) = ^ include/linux/percpu-defs.h:115:31: note: expanded from macro 'DEFINE_PER_CPU' DEFINE_PER_CPU_SECTION(type, name, "") ^ include/linux/percpu-defs.h:104:37: note: expanded from macro 'DEFINE_PER_CPU_SECTION' __PCPU_ATTRS(sec) __typeof__(type) name ^ 2 warnings and 2 errors generated. vim +/IRQ_WORK_INIT +617 kernel/rcu/tree.c 615 618 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org