tree: https://github.com/oracle/dtrace-linux-kernel v1/5.7 head: 55f507c4c80c4ed245c8a4ba2096d10b20bf7218 commit: 680d360bc21af4f790820585be4754c8f64afccb [3/20] waitfd: new syscall implementing waitpid() over fds config: riscv-randconfig-r015-20200607 (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project e429cffd4f228f70c1d9df0e5d77c08590dd9766) 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 riscv cross compiling tool for clang build # apt-get install binutils-riscv64-linux-gnu git checkout 680d360bc21af4f790820585be4754c8f64afccb # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv 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 >>, old ones prefixed by <<): #warning syscall waitfd not implemented ^ 1 warning generated. -- #warning syscall waitfd not implemented ^ 1 warning generated. -- arch/riscv/kernel/asm-offsets.c:14:6: warning: no previous prototype for function 'asm_offsets' [-Wmissing-prototypes] void asm_offsets(void) ^ arch/riscv/kernel/asm-offsets.c:14:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void asm_offsets(void) ^ static 1 warning generated. #warning syscall waitfd not implemented ^ 1 warning generated. --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org