[PATCH 0/3] tracing: Some cleanups of event trigger code

[PATCH 0/3] tracing: Some cleanups of event trigger code

[Steven Rostedt]

These are minor clean ups of the trace_events_trigger code.

- Rename event_trigger_alloc() to trigger_data_alloc() as it
  is supposed to be freed by trigger_data_free().

- Remove unneeded goto outs

- Add consistent cleanup in event_trigger_parse()


Miaoqian Lin (1):
      tracing: Fix error handling in event_trigger_parse()

Steven Rostedt (2):
      tracing: Rename event_trigger_alloc() to trigger_data_alloc()
      tracing: Remove unnecessary "goto out" that simply returns ret is trigger code

----
 kernel/trace/trace.h                |  8 ++---
 kernel/trace/trace_events_hist.c    |  2 +-
 kernel/trace/trace_events_trigger.c | 64 ++++++++++++++++---------------------
 3 files changed, 31 insertions(+), 43 deletions(-)

[PATCH 1/3] tracing: Rename event_trigger_alloc() to trigger_data_alloc()

[Steven Rostedt]

From: Steven Rostedt <rostedt@goodmis.org>

The function event_trigger_alloc() creates an event_trigger_data
descriptor and states that it needs to be freed via event_trigger_free().
This is incorrect, it needs to be freed by trigger_data_free() as
event_trigger_free() adds ref counting.

Rename event_trigger_alloc() to trigger_data_alloc() and state that it
needs to be freed via trigger_data_free(). This naming convention
was introducing bugs.

Fixes: 86599dbe2c527 ("tracing: Add helper functions to simplify event_command.parse() callback handling")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace.h                |  8 +++-----
 kernel/trace/trace_events_hist.c    |  2 +-
 kernel/trace/trace_events_trigger.c | 16 ++++++++--------
 3 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index a2639daea47b..053af6e4e7e0 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1774,6 +1774,9 @@ extern int event_enable_register_trigger(char *glob,
 extern void event_enable_unregister_trigger(char *glob,
 					    struct event_trigger_data *test,
 					    struct trace_event_file *file);
+extern struct event_trigger_data *
+trigger_data_alloc(struct event_command *cmd_ops, char *cmd, char *param,
+		   void *private_data);
 extern void trigger_data_free(struct event_trigger_data *data);
 extern int event_trigger_init(struct event_trigger_data *data);
 extern int trace_event_trigger_enable_disable(struct trace_event_file *file,
@@ -1800,11 +1803,6 @@ extern bool event_trigger_check_remove(const char *glob);
 extern bool event_trigger_empty_param(const char *param);
 extern int event_trigger_separate_filter(char *param_and_filter, char **param,
 					 char **filter, bool param_required);
-extern struct event_trigger_data *
-event_trigger_alloc(struct event_command *cmd_ops,
-		    char *cmd,
-		    char *param,
-		    void *private_data);
 extern int event_trigger_parse_num(char *trigger,
 				   struct event_trigger_data *trigger_data);
 extern int event_trigger_set_filter(struct event_command *cmd_ops,
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 58c9535f61df..1d536219b624 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -6826,7 +6826,7 @@ static int event_hist_trigger_parse(struct event_command *cmd_ops,
 		return PTR_ERR(hist_data);
 	}
 
-	trigger_data = event_trigger_alloc(cmd_ops, cmd, param, hist_data);
+	trigger_data = trigger_data_alloc(cmd_ops, cmd, param, hist_data);
 	if (!trigger_data) {
 		ret = -ENOMEM;
 		goto out_free;
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index b66b6d235d91..dac3344ee345 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -804,7 +804,7 @@ int event_trigger_separate_filter(char *param_and_filter, char **param,
 }
 
 /**
- * event_trigger_alloc - allocate and init event_trigger_data for a trigger
+ * trigger_data_alloc - allocate and init event_trigger_data for a trigger
  * @cmd_ops: The event_command operations for the trigger
  * @cmd: The cmd string
  * @param: The param string
@@ -815,14 +815,14 @@ int event_trigger_separate_filter(char *param_and_filter, char **param,
  * trigger_ops to assign to the event_trigger_data.  @private_data can
  * also be passed in and associated with the event_trigger_data.
  *
- * Use event_trigger_free() to free an event_trigger_data object.
+ * Use trigger_data_free() to free an event_trigger_data object.
  *
  * Return: The trigger_data object success, NULL otherwise
  */
-struct event_trigger_data *event_trigger_alloc(struct event_command *cmd_ops,
-					       char *cmd,
-					       char *param,
-					       void *private_data)
+struct event_trigger_data *trigger_data_alloc(struct event_command *cmd_ops,
+					      char *cmd,
+					      char *param,
+					      void *private_data)
 {
 	struct event_trigger_data *trigger_data;
 	const struct event_trigger_ops *trigger_ops;
@@ -989,7 +989,7 @@ event_trigger_parse(struct event_command *cmd_ops,
 		return ret;
 
 	ret = -ENOMEM;
-	trigger_data = event_trigger_alloc(cmd_ops, cmd, param, file);
+	trigger_data = trigger_data_alloc(cmd_ops, cmd, param, file);
 	if (!trigger_data)
 		goto out;
 
@@ -1793,7 +1793,7 @@ int event_enable_trigger_parse(struct event_command *cmd_ops,
 	enable_data->enable = enable;
 	enable_data->file = event_enable_file;
 
-	trigger_data = event_trigger_alloc(cmd_ops, cmd, param, enable_data);
+	trigger_data = trigger_data_alloc(cmd_ops, cmd, param, enable_data);
 	if (!trigger_data) {
 		kfree(enable_data);
 		goto out;
-- 
2.47.2

[PATCH 2/3] tracing: Fix error handling in event_trigger_parse()

[Steven Rostedt]

From: Miaoqian Lin <linmq006@gmail.com>

According to trigger_data_alloc() doc, trigger_data_free() should be
used to free an event_trigger_data object. This fixes a mismatch introduced
when kzalloc was replaced with trigger_data_alloc without updating
the corresponding deallocation calls.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Link: https://lore.kernel.org/20250318112737.4174-1-linmq006@gmail.com
Fixes: e1f187d09e11 ("tracing: Have existing event_command.parse() implementations use helpers")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
[ SDR: Changed event_trigger_alloc/free() to trigger_data_alloc/free() ]
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_trigger.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index dac3344ee345..c316badc608b 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -995,7 +995,7 @@ event_trigger_parse(struct event_command *cmd_ops,
 
 	if (remove) {
 		event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
-		kfree(trigger_data);
+		trigger_data_free(trigger_data);
 		ret = 0;
 		goto out;
 	}
@@ -1022,7 +1022,7 @@ event_trigger_parse(struct event_command *cmd_ops,
 
  out_free:
 	event_trigger_reset_filter(cmd_ops, trigger_data);
-	kfree(trigger_data);
+	trigger_data_free(trigger_data);
 	goto out;
 }
 
-- 
2.47.2

[PATCH 3/3] tracing: Remove unnecessary "goto out" that simply returns ret is trigger code

[Steven Rostedt]

From: Steven Rostedt <rostedt@goodmis.org>

There's several functions that have "goto out;" where the label out is just:

 out:
	return ret;

Simplify the code by just doing the return in the location and removing
all the out labels and jumps.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_trigger.c | 44 +++++++++++------------------
 1 file changed, 17 insertions(+), 27 deletions(-)

diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index c316badc608b..fdd1112388e9 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -552,16 +552,14 @@ static int register_trigger(char *glob,
 	lockdep_assert_held(&event_mutex);
 
 	list_for_each_entry(test, &file->triggers, list) {
-		if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
-			ret = -EEXIST;
-			goto out;
-		}
+		if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type)
+			return -EEXIST;
 	}
 
 	if (data->ops->init) {
 		ret = data->ops->init(data);
 		if (ret < 0)
-			goto out;
+			return ret;
 	}
 
 	list_add_rcu(&data->list, &file->triggers);
@@ -572,7 +570,6 @@ static int register_trigger(char *glob,
 		list_del_rcu(&data->list);
 		update_cond_flag(file);
 	}
-out:
 	return ret;
 }
 
@@ -770,7 +767,7 @@ int event_trigger_separate_filter(char *param_and_filter, char **param,
 	if (!param_and_filter) {
 		if (param_required)
 			ret = -EINVAL;
-		goto out;
+		return ret;
 	}
 
 	/*
@@ -781,7 +778,7 @@ int event_trigger_separate_filter(char *param_and_filter, char **param,
 	 */
 	if (!param_required && param_and_filter && !isdigit(param_and_filter[0])) {
 		*filter = param_and_filter;
-		goto out;
+		return ret;
 	}
 
 	/*
@@ -799,7 +796,6 @@ int event_trigger_separate_filter(char *param_and_filter, char **param,
 		if (!**filter)
 			*filter = NULL;
 	}
-out:
 	return ret;
 }
 
@@ -991,13 +987,12 @@ event_trigger_parse(struct event_command *cmd_ops,
 	ret = -ENOMEM;
 	trigger_data = trigger_data_alloc(cmd_ops, cmd, param, file);
 	if (!trigger_data)
-		goto out;
+		return ret;
 
 	if (remove) {
 		event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
 		trigger_data_free(trigger_data);
-		ret = 0;
-		goto out;
+		return 0;
 	}
 
 	ret = event_trigger_parse_num(param, trigger_data);
@@ -1017,13 +1012,12 @@ event_trigger_parse(struct event_command *cmd_ops,
 
 	/* Down the counter of trigger_data or free it if not used anymore */
 	event_trigger_free(trigger_data);
- out:
 	return ret;
 
  out_free:
 	event_trigger_reset_filter(cmd_ops, trigger_data);
 	trigger_data_free(trigger_data);
-	goto out;
+	return ret;
 }
 
 /**
@@ -1057,10 +1051,10 @@ int set_trigger_filter(char *filter_str,
 	s = strsep(&filter_str, " \t");
 
 	if (!strlen(s) || strcmp(s, "if") != 0)
-		goto out;
+		return ret;
 
 	if (!filter_str)
-		goto out;
+		return ret;
 
 	/* The filter is for the 'trigger' event, not the triggered event */
 	ret = create_event_filter(file->tr, file->event_call,
@@ -1104,7 +1098,6 @@ int set_trigger_filter(char *filter_str,
 			ret = -ENOMEM;
 		}
 	}
- out:
 	return ret;
 }
 
@@ -1772,7 +1765,7 @@ int event_enable_trigger_parse(struct event_command *cmd_ops,
 	ret = -EINVAL;
 	event_enable_file = find_event_file(tr, system, event);
 	if (!event_enable_file)
-		goto out;
+		return ret;
 
 #ifdef CONFIG_HIST_TRIGGERS
 	hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
@@ -1787,7 +1780,7 @@ int event_enable_trigger_parse(struct event_command *cmd_ops,
 
 	enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
 	if (!enable_data)
-		goto out;
+		return ret;
 
 	enable_data->hist = hist;
 	enable_data->enable = enable;
@@ -1796,7 +1789,7 @@ int event_enable_trigger_parse(struct event_command *cmd_ops,
 	trigger_data = trigger_data_alloc(cmd_ops, cmd, param, enable_data);
 	if (!trigger_data) {
 		kfree(enable_data);
-		goto out;
+		return ret;
 	}
 
 	if (remove) {
@@ -1804,7 +1797,7 @@ int event_enable_trigger_parse(struct event_command *cmd_ops,
 		kfree(trigger_data);
 		kfree(enable_data);
 		ret = 0;
-		goto out;
+		return ret;
 	}
 
 	/* Up the trigger_data count to make sure nothing frees it on failure */
@@ -1834,7 +1827,6 @@ int event_enable_trigger_parse(struct event_command *cmd_ops,
 		goto out_disable;
 
 	event_trigger_free(trigger_data);
- out:
 	return ret;
  out_disable:
 	trace_event_enable_disable(event_enable_file, 0, 1);
@@ -1845,7 +1837,7 @@ int event_enable_trigger_parse(struct event_command *cmd_ops,
 	event_trigger_free(trigger_data);
 	kfree(enable_data);
 
-	goto out;
+	return ret;
 }
 
 int event_enable_register_trigger(char *glob,
@@ -1865,15 +1857,14 @@ int event_enable_register_trigger(char *glob,
 		    (test->cmd_ops->trigger_type ==
 		     data->cmd_ops->trigger_type) &&
 		    (test_enable_data->file == enable_data->file)) {
-			ret = -EEXIST;
-			goto out;
+			return -EEXIST;
 		}
 	}
 
 	if (data->ops->init) {
 		ret = data->ops->init(data);
 		if (ret < 0)
-			goto out;
+			return ret;
 	}
 
 	list_add_rcu(&data->list, &file->triggers);
@@ -1884,7 +1875,6 @@ int event_enable_register_trigger(char *glob,
 		list_del_rcu(&data->list);
 		update_cond_flag(file);
 	}
-out:
 	return ret;
 }
 
-- 
2.47.2

Re: [PATCH 0/3] tracing: Some cleanups of event trigger code

[Tom Zanussi]

Hi Steve,

On Wed, 2025-05-07 at 10:53 -0400, Steven Rostedt wrote:
> These are minor clean ups of the trace_events_trigger code.
> 
> - Rename event_trigger_alloc() to trigger_data_alloc() as it
>   is supposed to be freed by trigger_data_free().
> 
> - Remove unneeded goto outs
> 
> - Add consistent cleanup in event_trigger_parse()
> 
> 
> Miaoqian Lin (1):
>       tracing: Fix error handling in event_trigger_parse()
> 
> Steven Rostedt (2):
>       tracing: Rename event_trigger_alloc() to trigger_data_alloc()
>       tracing: Remove unnecessary "goto out" that simply returns ret
> is trigger code
> 

These all look right to me, and were probably the original intent.

For all 3,

Reviewed-by: Tom Zanussi <zanussi@kernel.org>

Thanks,

Tom

> ----
>  kernel/trace/trace.h                |  8 ++---
>  kernel/trace/trace_events_hist.c    |  2 +-
>  kernel/trace/trace_events_trigger.c | 64 ++++++++++++++++-----------
> ----------
>  3 files changed, 31 insertions(+), 43 deletions(-)

Re: [PATCH 0/3] tracing: Some cleanups of event trigger code

[Steven Rostedt]

On Mon, 12 May 2025 15:47:53 -0500
Tom Zanussi <zanussi@kernel.org> wrote:

> > Miaoqian Lin (1):
> >       tracing: Fix error handling in event_trigger_parse()
> > 
> > Steven Rostedt (2):
> >       tracing: Rename event_trigger_alloc() to trigger_data_alloc()
> >       tracing: Remove unnecessary "goto out" that simply returns ret
> > is trigger code
> >   
> 
> These all look right to me, and were probably the original intent.
> 
> For all 3,
> 
> Reviewed-by: Tom Zanussi <zanussi@kernel.org>

Thanks Tom!

-- Steve