tree: https://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc.git topic-zol-remove head: 3138fa6a1832fdb830784a9781e63d739c0fdef7 commit: 3a2e16e5162c3e5ed9b8521d0bfefe96d0462cc9 [44/49] ARC: entry: rework (non-functional) config: arc-defconfig (attached as .config) compiler: arc-elf-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 3a2e16e5162c3e5ed9b8521d0bfefe96d0462cc9 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arc 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 <<): 303 | int syscall_trace_enter(struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~~ arch/arc/kernel/ptrace.c:311:17: warning: no previous prototype for 'syscall_trace_exit' [-Wmissing-prototypes] 311 | asmlinkage void syscall_trace_exit(struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~ vim +/syscall_trace_enter +303 arch/arc/kernel/ptrace.c 302 304 { 305 if (tracehook_report_syscall_entry(regs)) 306 return ULONG_MAX; 307 308 return regs->r8; 309 } 310 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org