Hi Daniel, [FYI, it's a private test report for your RFC patch.] [auto build test ERROR on tip/perf/core] [also build test ERROR on linux/master linus/master v5.12-rc6] [cannot apply to trace/for-next next-20210408] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Daniel-Bristot-de-Oliveira/hwlat... base: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git cface0326a6c2ae5c8f47bd466f07624b3e348a7 config: mips-randconfig-r002-20210408 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 56ea2e2fdd691136d5e6631fa0e447173694b82c) 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 mips cross compiling tool for clang build # apt-get install binutils-mips-linux-gnu # https://github.com/0day-ci/linux/commit/4e2f5d30c69f77756e8cf223acf55c2aa... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Daniel-Bristot-de-Oliveira/hwlat-improvements-and-osnoise-tracer/20210408-221655 git checkout 4e2f5d30c69f77756e8cf223acf55c2aa2657393 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): kernel/trace/trace_hwlat.c:122:28: warning: no previous prototype for function 'get_cpu_data' [-Wmissing-prototypes] struct hwlat_kthread_data *get_cpu_data(void) ^ kernel/trace/trace_hwlat.c:122:1: note: declare 'static' if the function is not intended to be used outside of this translation unit struct hwlat_kthread_data *get_cpu_data(void) ^ static if (!alloc_cpumask_var(&this_cpumask, GFP_KERNEL)) ^~~~~~~~~~~~~ include/linux/cpumask.h:767:53: note: passing argument to parameter 'mask' here static inline bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags) ^ 1 warning and 1 error generated. vim +496 kernel/trace/trace_hwlat.c 480 481 /** 482 * start_per_cpu_kthread - Kick off the hardware latency sampling/detector kthreads 483 * 484 * This starts the kernel threads that will sit on potentially all cpus and 485 * sample the CPU timestamp counter (TSC or similar) and look for potential 486 * hardware latencies. 487 */ 488 static int start_per_cpu_kthreads(struct trace_array *tr) 489 { 490 struct cpumask *current_mask = &save_cpumask; 491 struct cpumask *this_cpumask; 492 struct task_struct *kthread; 493 char comm[24]; 494 int cpu; 495 497 return -ENOMEM; 498 499 get_online_cpus(); 500 /* 501 * Run only on CPUs in which trace and hwlat are allowed to run. 502 */ 503 cpumask_and(current_mask, tr->tracing_cpumask, &hwlat_cpumask); 504 /* 505 * And the CPU is online. 506 */ 507 cpumask_and(current_mask, cpu_online_mask, current_mask); 508 put_online_cpus(); 509 510 for_each_online_cpu(cpu) 511 per_cpu(hwlat_per_cpu_data, cpu).kthread = NULL; 512 513 for_each_cpu(cpu, current_mask) { 514 snprintf(comm, 24, "hwlatd/%d", cpu); 515 516 kthread = kthread_create_on_cpu(kthread_fn, NULL, cpu, comm); 517 if (IS_ERR(kthread)) { 518 pr_err(BANNER "could not start sampling thread\n"); 519 stop_per_cpu_kthreads(); 520 return -ENOMEM; 521 } 522 523 per_cpu(hwlat_per_cpu_data, cpu).kthread = kthread; 524 wake_up_process(kthread); 525 } 526 527 return 0; 528 } 529 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org