tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 59fa6a163ffabc1bf25c5e0e33899e268a96d3cc commit: ea7ce6b17c1555b62690471f536eba6358ed3125 [6040/6048] set_memory: allow querying whether set_direct_map_*() is actually enabled config: arm64-randconfig-r031-20210128 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 48bdd676a1d1338c10541460bf5beb69ac17e451) 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/commit/?id=ea7ce6b17c1555b62690471f536eba6358ed3125 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 ea7ce6b17c1555b62690471f536eba6358ed3125 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All errors (new ones prefixed by >>): In file included from mm/kfence/core.c:26: >> arch/arm64/include/asm/kfence.h:17:2: error: implicit declaration of function 'set_memory_valid' [-Werror,-Wimplicit-function-declaration] set_memory_valid(addr, 1, !protect); ^ 1 error generated. vim +/set_memory_valid +17 arch/arm64/include/asm/kfence.h b6a4dacdad08f0 Marco Elver 2021-01-22 14 b6a4dacdad08f0 Marco Elver 2021-01-22 15 static inline bool kfence_protect_page(unsigned long addr, bool protect) b6a4dacdad08f0 Marco Elver 2021-01-22 16 { b6a4dacdad08f0 Marco Elver 2021-01-22 @17 set_memory_valid(addr, 1, !protect); b6a4dacdad08f0 Marco Elver 2021-01-22 18 b6a4dacdad08f0 Marco Elver 2021-01-22 19 return true; b6a4dacdad08f0 Marco Elver 2021-01-22 20 } b6a4dacdad08f0 Marco Elver 2021-01-22 21 :::::: The code at line 17 was first introduced by commit :::::: b6a4dacdad08f0a7db077346f89b36aa6891cde7 arm64, kfence: enable KFENCE for ARM64 :::::: TO: Marco Elver :::::: CC: Stephen Rothwell --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org