From: kernel test robot <lkp@intel.com>
To: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>
Cc: oe-kbuild-all@lists.linux.dev,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Subject: Re: [PATCH v4 2/4] tracing: Make the backup instance non-reusable
Date: Tue, 20 Jan 2026 16:17:05 +0800 [thread overview]
Message-ID: <202601201531.ng4kqZhn-lkp@intel.com> (raw)
In-Reply-To: <176887137556.578403.17994205756247311821.stgit@mhiramat.tok.corp.google.com>
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/20260120/202601201531.ng4kqZhn-lkp@intel.com/config)
compiler: arc-linux-gcc (GCC) 15.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260120/202601201531.ng4kqZhn-lkp@intel.com/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 <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202601201531.ng4kqZhn-lkp@intel.com/
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
next prev parent reply other threads:[~2026-01-20 8:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-20 1:09 [PATCH v4 0/4] tracing: Remove backup instance after read all Masami Hiramatsu (Google)
2026-01-20 1:09 ` [PATCH v4 1/4] tracing: Reset last_boot_info if ring buffer is reset Masami Hiramatsu (Google)
2026-01-20 1:09 ` [PATCH v4 2/4] tracing: Make the backup instance non-reusable Masami Hiramatsu (Google)
2026-01-20 8:17 ` kernel test robot [this message]
2026-01-20 1:09 ` [PATCH v4 3/4] tracing: Remove the backup instance automatically after read Masami Hiramatsu (Google)
2026-01-20 1:09 ` [PATCH v4 4/4] tracing/Documentation: Add a section about backup instance Masami Hiramatsu (Google)
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