kernel/trace/trace.c | 38 ++++++++++++++++---------------------- 1 file changed, 16 insertions(+), 22 deletions(-)
From: Steven Rostedt <rostedt@goodmis.org>
In trace.c, the function trace_create_maxlat_file() is defined behind the
#ifdef CONFIG_TRACER_MAX_TRACE block. The #else part defines it as:
#define trace_create_maxlat_file(tr, d_tracer) \
trace_create_file("tracing_max_latency", TRACE_MODE_WRITE, \
d_tracer, tr, &tracing_max_lat_fops)
But the one place that it it used has:
#ifdef CONFIG_TRACER_MAX_TRACE
trace_create_maxlat_file(tr, d_tracer);
#endif
Which is pointless and also wrong!
It only gets created when both CONFIG_TRACE_MAX_TRACE and CONFIG_FS_NOTIFY
is defined, but the file itself should not be dependent on
CONFIG_FS_NOTIFY. Always create that file when TRACE_MAX_TRACE is defined
regardless if FS_NOTIFY is or is not.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
Changes since v2: https://patch.msgid.link/20260206230410.4ed96e9f@robin
- On further inspection, tracing_max_latency should always be created if
CONFIG_TRACER_MAX_TRACE is defined regardless if CONFIG_FS_NOTIFY is.
kernel/trace/trace.c | 38 ++++++++++++++++----------------------
1 file changed, 16 insertions(+), 22 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 702ef851db45..d02c4004c718 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1912,10 +1912,7 @@ static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
unsigned long __read_mostly tracing_thresh;
#ifdef CONFIG_TRACER_MAX_TRACE
-static const struct file_operations tracing_max_lat_fops;
-
#ifdef LATENCY_FS_NOTIFY
-
static struct workqueue_struct *fsnotify_wq;
static void latency_fsnotify_workfn(struct work_struct *work)
@@ -1932,17 +1929,6 @@ static void latency_fsnotify_workfn_irq(struct irq_work *iwork)
queue_work(fsnotify_wq, &tr->fsnotify_work);
}
-static void trace_create_maxlat_file(struct trace_array *tr,
- struct dentry *d_tracer)
-{
- INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);
- init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);
- tr->d_max_latency = trace_create_file("tracing_max_latency",
- TRACE_MODE_WRITE,
- d_tracer, tr,
- &tracing_max_lat_fops);
-}
-
__init static int latency_fsnotify_init(void)
{
fsnotify_wq = alloc_workqueue("tr_max_lat_wq",
@@ -1967,14 +1953,22 @@ void latency_fsnotify(struct trace_array *tr)
*/
irq_work_queue(&tr->fsnotify_irqwork);
}
+#endif /* !LATENCY_FS_NOTIFY */
-#else /* !LATENCY_FS_NOTIFY */
-
-#define trace_create_maxlat_file(tr, d_tracer) \
- trace_create_file("tracing_max_latency", TRACE_MODE_WRITE, \
- d_tracer, tr, &tracing_max_lat_fops)
+static const struct file_operations tracing_max_lat_fops;
+static void trace_create_maxlat_file(struct trace_array *tr,
+ struct dentry *d_tracer)
+{
+#ifdef LATENCY_FS_NOTIFY
+ INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);
+ init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);
#endif
+ tr->d_max_latency = trace_create_file("tracing_max_latency",
+ TRACE_MODE_WRITE,
+ d_tracer, tr,
+ &tracing_max_lat_fops);
+}
/*
* Copy the new maximum trace into the separate maximum-trace
@@ -2109,7 +2103,9 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
__update_max_tr(tr, tsk, cpu);
arch_spin_unlock(&tr->max_lock);
}
-
+#else /* !CONFIG_TRACER_MAX_TRACE */
+static inline void trace_create_maxlat_file(struct trace_array *tr,
+ struct dentry *d_tracer) { }
#endif /* CONFIG_TRACER_MAX_TRACE */
struct pipe_wait {
@@ -10664,9 +10660,7 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
create_trace_options_dir(tr);
-#ifdef CONFIG_TRACER_MAX_TRACE
trace_create_maxlat_file(tr, d_tracer);
-#endif
if (ftrace_create_function_files(tr, d_tracer))
MEM_FAIL(1, "Could not allocate function filter files");
--
2.51.0Hi Steven,
kernel test robot noticed the following build errors:
[auto build test ERROR on trace/for-next]
[also build test ERROR on linus/master v6.19-rc8 next-20260205]
[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/Steven-Rostedt/tracing-Clean-up-use-of-trace_create_maxlat_file/20260208-081407
base: https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace for-next
patch link: https://lore.kernel.org/r/20260207191101.0e014abd%40robin
patch subject: [PATCH] tracing: Clean up use of trace_create_maxlat_file()
config: arm-randconfig-r071-20260208 (https://download.01.org/0day-ci/archive/20260208/202602081759.QQ7Yu6SK-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 11.5.0
smatch version: v0.5.0-8994-gd50c5a4c
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260208/202602081759.QQ7Yu6SK-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/202602081759.QQ7Yu6SK-lkp@intel.com/
All errors (new ones prefixed by >>):
kernel/trace/trace.c: In function 'trace_create_maxlat_file':
>> kernel/trace/trace.c:1967:13: error: 'struct trace_array' has no member named 'd_max_latency'; did you mean 'max_latency'?
1967 | tr->d_max_latency = trace_create_file("tracing_max_latency",
| ^~~~~~~~~~~~~
| max_latency
vim +1967 kernel/trace/trace.c
1959
1960 static void trace_create_maxlat_file(struct trace_array *tr,
1961 struct dentry *d_tracer)
1962 {
1963 #ifdef LATENCY_FS_NOTIFY
1964 INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);
1965 init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);
1966 #endif
> 1967 tr->d_max_latency = trace_create_file("tracing_max_latency",
1968 TRACE_MODE_WRITE,
1969 d_tracer, tr,
1970 &tracing_max_lat_fops);
1971 }
1972
--
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