tree: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2020.05.25a head: 1e9451642683146552713c5ce6d269ae378eacd5 commit: 786a25497743696d79592b864cafbfe48787e6e1 [51/63] refperf: Add a test to measure performance of read-side synchronization config: x86_64-allyesconfig (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 3393cc4cebf9969db94dc424b7a2b6195589c33b) 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 x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu git checkout 786a25497743696d79592b864cafbfe48787e6e1 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 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 <<): void reset_readers(int n) ^ kernel/rcu/refperf.c:298:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void reset_readers(int n) ^ static u64 process_durations(int n) ^ kernel/rcu/refperf.c:311:1: note: declare 'static' if the function is not intended to be used outside of this translation unit u64 process_durations(int n) ^ static 2 warnings generated. vim +/reset_readers +298 kernel/rcu/refperf.c 297 299 { 300 int i; 301 struct reader_task *rt; 302 303 for (i = 0; i < n; i++) { 304 rt = &(reader_tasks[i]); 305 306 rt->last_duration_ns = 0; 307 } 308 } 309 310 // Print the results of each reader and return the sum of all their durations. 312 { 313 int i; 314 struct reader_task *rt; 315 char buf1[64]; 316 char buf[512]; 317 u64 sum = 0; 318 319 buf[0] = 0; 320 sprintf(buf, "Experiment #%d (Format: <THREAD-NUM>:<Total loop time in ns>)", 321 exp_idx); 322 323 for (i = 0; i <= n && !torture_must_stop(); i++) { 324 rt = &(reader_tasks[i]); 325 sprintf(buf1, "%d: %llu\t", i, rt->last_duration_ns); 326 327 if (i % 5 == 0) 328 strcat(buf, "\n"); 329 strcat(buf, buf1); 330 331 sum += rt->last_duration_ns; 332 } 333 strcat(buf, "\n"); 334 335 PERFOUT("%s\n", buf); 336 337 return sum; 338 } 339 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org