[PATCH v2] tracing: Show the tracer options in boot-time created instance

[PATCH v2] tracing: Show the tracer options in boot-time created instance

[Masami Hiramatsu (Google)]

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Since tracer_init_tracefs_work_func() only updates the tracer options
for the global_trace, the instances created by the kernel cmdline
do not have those options.

Fix to update tracer options for those boot-time created instances
to show those options.

Fixes: 428add559b69 ("tracing: Have tracer option be instance specific")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
  Change in v2:
   - Fix update_tracer_options() to update all instances.
   - Update tracer_options_updated after update all instances.
---
 kernel/trace/trace.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8ae95800592d..4a6784057855 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -10231,11 +10231,16 @@ static __init int __update_tracer_options(struct trace_array *tr)
 	return ret;
 }
 
-static __init void update_tracer_options(struct trace_array *tr)
+static __init void update_tracer_options(void)
 {
+	struct trace_array *tr;
+
 	guard(mutex)(&trace_types_lock);
+
+	list_for_each_entry(tr, &ftrace_trace_arrays, list)
+		__update_tracer_options(tr);
+
 	tracer_options_updated = true;
-	__update_tracer_options(tr);
 }
 
 /* Must have trace_types_lock held */
@@ -10937,7 +10942,7 @@ static __init void tracer_init_tracefs_work_func(struct work_struct *work)
 
 	create_trace_instances(NULL);
 
-	update_tracer_options(&global_trace);
+	update_tracer_options();
 }
 
 static __init int tracer_init_tracefs(void)

Re: [PATCH v2] tracing: Show the tracer options in boot-time created instance

[Masami Hiramatsu]

On Wed, 19 Nov 2025 09:21:34 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:

> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> 
> Since tracer_init_tracefs_work_func() only updates the tracer options
> for the global_trace, the instances created by the kernel cmdline
> do not have those options.
> 
> Fix to update tracer options for those boot-time created instances
> to show those options.
> 

Wait, this seems not updating the global instance. Let me fix it.
(ftracetest found it.)

Thanks,

> Fixes: 428add559b69 ("tracing: Have tracer option be instance specific")
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
>   Change in v2:
>    - Fix update_tracer_options() to update all instances.
>    - Update tracer_options_updated after update all instances.
> ---
>  kernel/trace/trace.c |   11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 8ae95800592d..4a6784057855 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -10231,11 +10231,16 @@ static __init int __update_tracer_options(struct trace_array *tr)
>  	return ret;
>  }
>  
> -static __init void update_tracer_options(struct trace_array *tr)
> +static __init void update_tracer_options(void)
>  {
> +	struct trace_array *tr;
> +
>  	guard(mutex)(&trace_types_lock);
> +
> +	list_for_each_entry(tr, &ftrace_trace_arrays, list)
> +		__update_tracer_options(tr);
> +
>  	tracer_options_updated = true;
> -	__update_tracer_options(tr);
>  }
>  
>  /* Must have trace_types_lock held */
> @@ -10937,7 +10942,7 @@ static __init void tracer_init_tracefs_work_func(struct work_struct *work)
>  
>  	create_trace_instances(NULL);
>  
> -	update_tracer_options(&global_trace);
> +	update_tracer_options();
>  }
>  
>  static __init int tracer_init_tracefs(void)
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

Re: [PATCH v2] tracing: Show the tracer options in boot-time created instance

[Masami Hiramatsu]

On Wed, 19 Nov 2025 13:39:42 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:
> > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> > index 8ae95800592d..4a6784057855 100644
> > --- a/kernel/trace/trace.c
> > +++ b/kernel/trace/trace.c
> > @@ -10231,11 +10231,16 @@ static __init int __update_tracer_options(struct trace_array *tr)
> >  	return ret;
> >  }
> >  
> > -static __init void update_tracer_options(struct trace_array *tr)
> > +static __init void update_tracer_options(void)
> >  {
> > +	struct trace_array *tr;
> > +
> >  	guard(mutex)(&trace_types_lock);
> > +
> > +	list_for_each_entry(tr, &ftrace_trace_arrays, list)
> > +		__update_tracer_options(tr);
> > +
> >  	tracer_options_updated = true;

Oops, I misunderstood this flag. This should be set *before* calling
__update_tracer_options(). Not updated.

Thanks,

-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>