tree: https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git rcu/refperf head: df3410c1f7436cf0a91127b2629a33923cc62140 commit: e9577008869a8d050252b346823d54ab84af4021 [1/3] test config: i386-randconfig-r015-20200514 (attached as .config) compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 reproduce: git checkout e9577008869a8d050252b346823d54ab84af4021 # save the attached .config to linux build tree make ARCH=i386 If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; All error/warnings (new ones prefixed by >>, old ones prefixed by <<): kernel/rcu/tree.c: In function 'rcu_pr_kthread': kernel/rcu/tree.c:3852:35: warning: unused variable 'spincnt2' [-Wunused-variable] unsigned long spincnt, spincnt1, spincnt2, x=0; ^~~~~~~~ kernel/rcu/tree.c:3852:25: warning: unused variable 'spincnt1' [-Wunused-variable] unsigned long spincnt, spincnt1, spincnt2, x=0; ^~~~~~~~ kernel/rcu/tree.c:3851:7: warning: unused variable 'work' [-Wunused-variable] char work, *workp = this_cpu_ptr(&rcu_data.rcu_pr_has_work); ^~~~ kernel/rcu/tree.c:3850:16: warning: unused variable 'statusp' [-Wunused-variable] unsigned int *statusp = this_cpu_ptr(&rcu_data.rcu_pr_kthread_status); ^~~~~~~ kernel/rcu/tree.c: In function 'rcu_spawn_pr_kthreads': &pr_ops); ^ In file included from kernel/rcu/tree.c:23:0: include/linux/proc_fs.h:79:24: note: expected 'const struct proc_ops *' but argument is of type 'const struct file_operations *' struct proc_dir_entry *proc_create(const char *name, umode_t mode, struct proc_dir_entry *parent, const struct proc_ops *proc_ops); ^~~~~~~~~~~ kernel/rcu/tree.c: In function 'pr_proc_write': } ^ cc1: some warnings being treated as errors vim +/proc_create +3979 kernel/rcu/tree.c 3935 3936 ssize_t pr_proc_write(struct file * f, const char __user * b, size_t s, loff_t * off) 3937 { 3938 u64 before, after; 3939 3940 WRITE_ONCE(work_type, PERCPU_RWSEM); 3941 repeat: 3942 smp_mb(); 3943 3944 before = ktime_get_mono_fast_ns(); 3945 do_one_pr_test(); 3946 after = ktime_get_mono_fast_ns(); 3947 3948 pr_err("Total time: %lu us , type: %s\n", (unsigned long)((after - before) / 1000), 3949 (work_type == PERCPU_RWSEM ? "percpu-rwsem" : "rwsem") ); 3950 3951 if (work_type != RWSEM) { 3952 work_type = RWSEM; 3953 msleep(100); 3954 goto repeat; 3955 } 3956 3958 3959 static const struct file_operations pr_ops = { 3960 .write = pr_proc_write, 3961 .llseek = default_llseek, 3962 }; 3963 3964 /* 3965 * Spawn boost kthreads -- called as soon as the scheduler is running. 3966 */ 3967 static void __init rcu_spawn_pr_kthreads(void) 3968 { 3969 int cpu; 3970 3971 for_each_possible_cpu(cpu) 3972 per_cpu(rcu_data.rcu_pr_has_work, cpu) = 0; 3973 3974 if (WARN_ONCE(smpboot_register_percpu_thread(&rcu_pr_thread_spec), 3975 "%s: Could not start rcub kthread, OOM is now expected behavior\n", __func__)) 3976 return; 3977 3978 proc_create("prw_test", 0777, NULL, 3980 3981 /* 3982 for_each_online_cpu(cpu) { 3983 pr_err("waking up thread on online cpu %d\n", cpu); 3984 per_cpu(rcu_data.rcu_pr_has_work, cpu) = 1; 3985 smp_mb(); 3986 wake_up_process(per_cpu(rcu_data.pr_kthread, cpu)); 3987 } 3988 */ 3989 } 3990 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org