tree: https://github.com/alibaba/cloud-kernel.git linux-next head: 1d6103ae4cce545c231de9498d0e70564e7b734e commit: 1e53713f5f83c3ee86642edcdd03bb5ed9019ea4 [10939/11168] kvm: x86: add host poll control msrs config: x86_64-randconfig-a003-20200526 (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 3393cc4cebf9969db94dc424b7a2b6195589c33b) 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 git checkout 1e53713f5f83c3ee86642edcdd03bb5ed9019ea4 # 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: kbuild test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>, old ones prefixed by <<): arch/x86/kvm/x86.c:9045:5: warning: no previous prototype for function 'kvm_arch_post_init_vm' [-Wmissing-prototypes] int kvm_arch_post_init_vm(struct kvm *kvm) ^ arch/x86/kvm/x86.c:9045:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int kvm_arch_post_init_vm(struct kvm *kvm) ^ static arch/x86/kvm/x86.c:9151:6: warning: no previous prototype for function 'kvm_arch_pre_destroy_vm' [-Wmissing-prototypes] void kvm_arch_pre_destroy_vm(struct kvm *kvm) ^ arch/x86/kvm/x86.c:9151:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void kvm_arch_pre_destroy_vm(struct kvm *kvm) ^ static bool kvm_arch_no_poll(struct kvm_vcpu *vcpu) ^ arch/x86/kvm/x86.c:9760:1: note: declare 'static' if the function is not intended to be used outside of this translation unit bool kvm_arch_no_poll(struct kvm_vcpu *vcpu) ^ static 3 warnings generated. vim +/kvm_arch_no_poll +9760 arch/x86/kvm/x86.c 9759 9761 { 9762 return (vcpu->arch.msr_kvm_poll_control & 1) == 0; 9763 } 9764 EXPORT_SYMBOL_GPL(kvm_arch_no_poll); 9765 9766 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org