Commit 5aa0d18d authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt (Google)
Browse files

tracing: Have add_tracer_options() error pass up to callers 

The function add_tracer_options() can fail, but currently it is ignored.
Pass the status of add_tracer_options() up to adding a new tracer as well
as when an instance is created. Have the instance creation fail if the
add_tracer_options() fail.

Only print a warning for the top level instance, like it does with other
failures.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://patch.msgid.link/20251105161935.375299297@kernel.org


Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent c7bed15c

kernel/trace/trace.c

+34 −21
Original line number Diff line number Diff line
@@ -2302,7 +2302,7 @@ static inline int do_run_tracer_selftest(struct tracer *type) 
}

#endif /* CONFIG_FTRACE_STARTUP_TEST */



static void add_tracer_options(struct trace_array *tr, struct tracer *t);

static int add_tracer_options(struct trace_array *tr, struct tracer *t);



static void __init apply_trace_boot_options(void);
@@ -2353,9 +2353,14 @@ int __init register_tracer(struct tracer *type) 
	if (ret < 0)

		goto out;



	ret = add_tracer_options(&global_trace, type);

	if (ret < 0) {

		pr_warn("Failed to create tracer options for %s\n", type->name);

		goto out;

	}



	type->next = trace_types;

	trace_types = type;

	add_tracer_options(&global_trace, type);



 out:

	mutex_unlock(&trace_types_lock);
@@ -6221,7 +6226,7 @@ int tracing_update_buffers(struct trace_array *tr) 


struct trace_option_dentry;



static void

static int

create_trace_option_files(struct trace_array *tr, struct tracer *tracer);



/*
@@ -6243,17 +6248,17 @@ static void tracing_set_nop(struct trace_array *tr) 


static bool tracer_options_updated;



static void add_tracer_options(struct trace_array *tr, struct tracer *t)

static int add_tracer_options(struct trace_array *tr, struct tracer *t)

{

	/* Only enable if the directory has been created already. */

	if (!tr->dir && !(tr->flags & TRACE_ARRAY_FL_GLOBAL))

		return;

		return 0;



	/* Only create trace option files after update_tracer_options finish */

	if (!tracer_options_updated)

		return;

		return 0;



	create_trace_option_files(tr, t);

	return create_trace_option_files(tr, t);

}



int tracing_set_tracer(struct trace_array *tr, const char *buf)
@@ -9585,7 +9590,7 @@ create_trace_option_file(struct trace_array *tr, 


}



static void

static int

create_trace_option_files(struct trace_array *tr, struct tracer *tracer)

{

	struct trace_option_dentry *topts;
@@ -9596,24 +9601,24 @@ create_trace_option_files(struct trace_array *tr, struct tracer *tracer) 
	int i;



	if (!tracer)

		return;

		return 0;



	flags = tracer->flags;



	if (!flags || !flags->opts)

		return;

		return 0;



	/*

	 * If this is an instance, only create flags for tracers

	 * the instance may have.

	 */

	if (!trace_ok_for_array(tracer, tr))

		return;

		return 0;



	for (i = 0; i < tr->nr_topts; i++) {

		/* Make sure there's no duplicate flags. */

		if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))

			return;

			return -EINVAL;

	}



	opts = flags->opts;
@@ -9623,13 +9628,13 @@ create_trace_option_files(struct trace_array *tr, struct tracer *tracer) 


	topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);

	if (!topts)

		return;

		return 0;



	tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),

			    GFP_KERNEL);

	if (!tr_topts) {

		kfree(topts);

		return;

		return -ENOMEM;

	}



	tr->topts = tr_topts;
@@ -9644,6 +9649,7 @@ create_trace_option_files(struct trace_array *tr, struct tracer *tracer) 
			  "Failed to create trace option: %s",

			  opts[cnt].name);

	}

	return 0;

}



static struct dentry *
@@ -10094,15 +10100,18 @@ static void init_trace_flags_index(struct trace_array *tr) 
		tr->trace_flags_index[i] = i;

}



static void __update_tracer_options(struct trace_array *tr)

static int __update_tracer_options(struct trace_array *tr)

{

	struct tracer *t;

	int ret = 0;



	for (t = trace_types; t && !ret; t = t->next)

		ret = add_tracer_options(tr, t);



	for (t = trace_types; t; t = t->next)

		add_tracer_options(tr, t);

	return ret;

}



static void update_tracer_options(struct trace_array *tr)

static __init void update_tracer_options(struct trace_array *tr)

{

	guard(mutex)(&trace_types_lock);

	tracer_options_updated = true;
@@ -10151,10 +10160,14 @@ static int trace_array_create_dir(struct trace_array *tr) 
	}



	init_tracer_tracefs(tr, tr->dir);

	__update_tracer_options(tr);



	ret = __update_tracer_options(tr);

	if (ret) {

		event_trace_del_tracer(tr);

		tracefs_remove(tr->dir);

		return ret;

	}

	return 0;

}



static struct trace_array *

trace_array_create_systems(const char *name, const char *systems,