Hi Masami, kernel test robot noticed the following build warnings:
[auto build test WARNING on trace/for-next] [also build test WARNING on linus/master v6.19-rc6 next-20260119] [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#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Masami-Hiramatsu-Google/tracing-Reset-last_boot_info-if-ring-buffer-is-reset/20260120-091429 base: https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace for-next patch link: https://lore.kernel.org/r/176887137556.578403.17994205756247311821.stgit%40mhiramat.tok.corp.google.com patch subject: [PATCH v4 2/4] tracing: Make the backup instance non-reusable config: arc-defconfig (https://download.01.org/0day-ci/archive/20260120/[email protected]/config) compiler: arc-linux-gcc (GCC) 15.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260120/[email protected]/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <[email protected]> | Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/ All warnings (new ones prefixed by >>): kernel/trace/trace.c: In function 'tracing_init_tracefs_percpu': >> kernel/trace/trace.c:9398:17: warning: variable 'writable_mode' set but not >> used [-Wunused-but-set-variable] 9398 | umode_t writable_mode = TRACE_MODE_WRITE; | ^~~~~~~~~~~~~ vim +/writable_mode +9398 kernel/trace/trace.c 9393 9394 static void 9395 tracing_init_tracefs_percpu(struct trace_array *tr, long cpu) 9396 { 9397 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu); > 9398 umode_t writable_mode = TRACE_MODE_WRITE; 9399 struct dentry *d_cpu; 9400 char cpu_dir[30]; /* 30 characters should be more than enough */ 9401 9402 if (!d_percpu) 9403 return; 9404 9405 if (trace_array_is_readonly(tr)) 9406 writable_mode = TRACE_MODE_READ; 9407 9408 snprintf(cpu_dir, 30, "cpu%ld", cpu); 9409 d_cpu = tracefs_create_dir(cpu_dir, d_percpu); 9410 if (!d_cpu) { 9411 pr_warn("Could not create tracefs '%s' entry\n", cpu_dir); 9412 return; 9413 } 9414 9415 /* per cpu trace_pipe */ 9416 trace_create_cpu_file("trace_pipe", TRACE_MODE_READ, d_cpu, 9417 tr, cpu, &tracing_pipe_fops); 9418 9419 /* per cpu trace */ 9420 trace_create_cpu_file("trace", TRACE_MODE_WRITE, d_cpu, 9421 tr, cpu, &tracing_fops); 9422 9423 trace_create_cpu_file("trace_pipe_raw", TRACE_MODE_READ, d_cpu, 9424 tr, cpu, &tracing_buffers_fops); 9425 9426 trace_create_cpu_file("stats", TRACE_MODE_READ, d_cpu, 9427 tr, cpu, &tracing_stats_fops); 9428 9429 trace_create_cpu_file("buffer_size_kb", TRACE_MODE_READ, d_cpu, 9430 tr, cpu, &tracing_entries_fops); 9431 9432 if (tr->range_addr_start) 9433 trace_create_cpu_file("buffer_meta", TRACE_MODE_READ, d_cpu, 9434 tr, cpu, &tracing_buffer_meta_fops); 9435 #ifdef CONFIG_TRACER_SNAPSHOT 9436 if (!tr->range_addr_start) { 9437 trace_create_cpu_file("snapshot", TRACE_MODE_WRITE, d_cpu, 9438 tr, cpu, &snapshot_fops); 9439 9440 trace_create_cpu_file("snapshot_raw", TRACE_MODE_READ, d_cpu, 9441 tr, cpu, &snapshot_raw_fops); 9442 } 9443 #endif 9444 } 9445 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
