tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: fb57b1fabcb28f358901b2df90abd2b48abc1ca8 commit: f87dc808009ac86c790031627698ef1a34c31e25 [4042/10701] rcuperf: Add ability to increase object allocation size config: powerpc-randconfig-r016-20200519 (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 135b877874fae96b4372c8a3fbfaa8ff44ff86e3) reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install powerpc cross compiling tool for clang build # apt-get install binutils-powerpc-linux-gnu git checkout f87dc808009ac86c790031627698ef1a34c31e25 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc 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 <<): pr_alert("kfree object size=%lun", kfree_mult * sizeof(struct kfree_obj)); ~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ %u include/linux/printk.h:295:35: note: expanded from macro 'pr_alert' printk(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__) ~~~ ^~~~~~~~~~~ 1 warning generated. vim +726 kernel/rcu/rcuperf.c 708 709 static int __init 710 kfree_perf_init(void) 711 { 712 long i; 713 int firsterr = 0; 714 715 kfree_nrealthreads = compute_real(kfree_nthreads); 716 /* Start up the kthreads. */ 717 if (shutdown) { 718 init_waitqueue_head(&shutdown_wq); 719 firsterr = torture_create_kthread(kfree_perf_shutdown, NULL, 720 shutdown_task); 721 if (firsterr) 722 goto unwind; 723 schedule_timeout_uninterruptible(1); 724 } 725 727 728 kfree_reader_tasks = kcalloc(kfree_nrealthreads, sizeof(kfree_reader_tasks[0]), 729 GFP_KERNEL); 730 if (kfree_reader_tasks == NULL) { 731 firsterr = -ENOMEM; 732 goto unwind; 733 } 734 735 for (i = 0; i < kfree_nrealthreads; i++) { 736 firsterr = torture_create_kthread(kfree_perf_thread, (void *)i, 737 kfree_reader_tasks[i]); 738 if (firsterr) 739 goto unwind; 740 } 741 742 while (atomic_read(&n_kfree_perf_thread_started) < kfree_nrealthreads) 743 schedule_timeout_uninterruptible(1); 744 745 torture_init_end(); 746 return 0; 747 748 unwind: 749 torture_init_end(); 750 kfree_perf_cleanup(); 751 return firsterr; 752 } 753 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org