Hi Andrew, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 18250b538735142307082e4e99e3ae5c12d44013 commit: f79e616f27ab6cd74deb0995a8eead3d1c9d65af [7904/13394] KVM: arm64: Use BUG and BUG_ON in nVHE hyp config: arm64-randconfig-r005-20210418 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project dd68942f1d79986267a58c9a9924522680d5c82b) 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 arm64 cross compiling tool for clang build # apt-get install binutils-aarch64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commi... git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout f79e616f27ab6cd74deb0995a8eead3d1c9d65af # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=arm64 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 >>): void __noreturn hyp_panic(void) ^ arch/arm64/kvm/hyp/vhe/switch.c:217:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __noreturn hyp_panic(void) ^ static arch/arm64/kvm/hyp/vhe/switch.c:227:17: warning: no previous prototype for function 'kvm_unexpected_el2_exception' [-Wmissing-prototypes] asmlinkage void kvm_unexpected_el2_exception(void) ^ arch/arm64/kvm/hyp/vhe/switch.c:227:12: note: declare 'static' if the function is not intended to be used outside of this translation unit asmlinkage void kvm_unexpected_el2_exception(void) ^ static 2 warnings generated. -- void __noreturn hyp_panic(void) ^ arch/arm64/kvm/hyp/nvhe/switch.c:264:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __noreturn hyp_panic(void) ^ static arch/arm64/kvm/hyp/nvhe/switch.c:286:17: warning: no previous prototype for function 'kvm_unexpected_el2_exception' [-Wmissing-prototypes] asmlinkage void kvm_unexpected_el2_exception(void) ^ arch/arm64/kvm/hyp/nvhe/switch.c:286:12: note: declare 'static' if the function is not intended to be used outside of this translation unit asmlinkage void kvm_unexpected_el2_exception(void) ^ static 2 warnings generated. vim +/hyp_panic +217 arch/arm64/kvm/hyp/vhe/switch.c 09cf57eba30424 David Brazdil 2020-06-25 216 6a0259ed29bba8 Andrew Scull 2020-09-15 @217 void __noreturn hyp_panic(void) 09cf57eba30424 David Brazdil 2020-06-25 218 { 09cf57eba30424 David Brazdil 2020-06-25 219 u64 spsr = read_sysreg_el2(SYS_SPSR); 09cf57eba30424 David Brazdil 2020-06-25 220 u64 elr = read_sysreg_el2(SYS_ELR); 96d389ca10110d Rob Herring 2020-10-28 221 u64 par = read_sysreg_par(); 09cf57eba30424 David Brazdil 2020-06-25 222 6a0259ed29bba8 Andrew Scull 2020-09-15 223 __hyp_call_panic(spsr, elr, par); 09cf57eba30424 David Brazdil 2020-06-25 224 unreachable(); 09cf57eba30424 David Brazdil 2020-06-25 225 } e9ee186bb735bf James Morse 2020-08-21 226 :::::: The code at line 217 was first introduced by commit :::::: 6a0259ed29bba83653a36fabcdf6b06aecd78596 KVM: arm64: Remove hyp_panic arguments :::::: TO: Andrew Scull <ascull(a)google.com&gt; :::::: CC: Marc Zyngier <maz(a)kernel.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org