[kbuild-all] arch/arm/kvm/../../../virt/kvm/arm/arm.c:147:5: warning: no previous prototype for 'kvm_arch_create_vcpu_debugfs'

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 1df0d8960499e58963fd6c8ac75e544f2b417b29 commit: 741cbbae0768b828be2d48331eb371a4f08bbea8 KVM: remove kvm_arch_has_vcpu_debugfs() date: 11 months ago config: arm-axm55xx_defconfig (attached as .config) compiler: arm-linux-gnueabi-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 git checkout 741cbbae0768b828be2d48331eb371a4f08bbea8 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): 147 | int kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ vim +/kvm_arch_create_vcpu_debugfs +147 arch/arm/kvm/../../../virt/kvm/arm/arm.c 749cf76c5a363e arch/arm/kvm/arm.c Christoffer Dall 2013-01-20 146 235539b48a2357 arch/arm/kvm/arm.c Luiz Capitulino 2016-09-07 @147 int kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu) 235539b48a2357 arch/arm/kvm/arm.c Luiz Capitulino 2016-09-07 148 { 235539b48a2357 arch/arm/kvm/arm.c Luiz Capitulino 2016-09-07 149 return 0; 235539b48a2357 arch/arm/kvm/arm.c Luiz Capitulino 2016-09-07 150 } 235539b48a2357 arch/arm/kvm/arm.c Luiz Capitulino 2016-09-07 151 :::::: The code at line 147 was first introduced by commit :::::: 235539b48a2357da28f52d66d04bec04f3dcb9dd kvm: add stubs for arch specific debugfs support :::::: TO: Luiz Capitulino <lcapitulino(a)redhat.com&gt; :::::: CC: Paolo Bonzini <pbonzini(a)redhat.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org