Merge tag 'trace-v6.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Fix osnoise duration type to 64bit not 32bit

 - Have histogram triggers be able to handle an unexpected NULL pointer
   for the record event, which can happen when the histogram first
   starts up

 - Clear out ring buffers when dynamic events are removed, as the type
   that is saved in the ring buffer is used to read the event, and a
   stale type that is reused by another event could cause use after free
   issues

 - Trivial comment fix

 - Fix memory leak in user_event_create()

* tag 'trace-v6.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Free buffers when a used dynamic event is removed
  tracing: Add tracing_reset_all_online_cpus_unlocked() function
  tracing: Fix race where histograms can be called before the event
  tracing/osnoise: Fix duration type
  tracing/user_events: Fix memory leak in user_event_create()
  tracing/hist: add in missing * in comment blocks

Author: torvalds

kernel/trace/trace.c

@@ -2180,10 +2180,12 @@ void tracing_reset_online_cpus(struct array_buffer *buf)
 }
 
 /* Must have trace_types_lock held */
-void tracing_reset_all_online_cpus(void)
+void tracing_reset_all_online_cpus_unlocked(void)
 {
 	struct trace_array *tr;
 
+	lockdep_assert_held(&trace_types_lock);
+
 	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
 		if (!tr->clear_trace)
 			continue;
@@ -2195,6 +2197,13 @@ void tracing_reset_all_online_cpus(void)
 	}
 }
 
+void tracing_reset_all_online_cpus(void)
+{
+	mutex_lock(&trace_types_lock);
+	tracing_reset_all_online_cpus_unlocked();
+	mutex_unlock(&trace_types_lock);
+}
+
 /*
  * The tgid_map array maps from pid to tgid; i.e. the value stored at index i
  * is the tgid last observed corresponding to pid=i.

kernel/trace/trace.h

@@ -580,6 +580,7 @@ int tracing_is_enabled(void);
 void tracing_reset_online_cpus(struct array_buffer *buf);
 void tracing_reset_current(int cpu);
 void tracing_reset_all_online_cpus(void);
+void tracing_reset_all_online_cpus_unlocked(void);
 int tracing_open_generic(struct inode *inode, struct file *filp);
 int tracing_open_generic_tr(struct inode *inode, struct file *filp);
 bool tracing_is_disabled(void);

kernel/trace/trace_dynevent.c

@@ -118,6 +118,7 @@ int dyn_event_release(const char *raw_command, struct dyn_event_operations *type
 		if (ret)
 			break;
 	}
+	tracing_reset_all_online_cpus();
 	mutex_unlock(&event_mutex);
 out:
 	argv_free(argv);
@@ -214,6 +215,7 @@ int dyn_events_release_all(struct dyn_event_operations *type)
 			break;
 	}
 out:
+	tracing_reset_all_online_cpus();
 	mutex_unlock(&event_mutex);
 
 	return ret;

kernel/trace/trace_events.c

@@ -2880,7 +2880,10 @@ static int probe_remove_event_call(struct trace_event_call *call)
 		 * TRACE_REG_UNREGISTER.
 		 */
 		if (file->flags & EVENT_FILE_FL_ENABLED)
-			return -EBUSY;
+			goto busy;
+
+		if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
+			tr->clear_trace = true;
 		/*
 		 * The do_for_each_event_file_safe() is
 		 * a double loop. After finding the call for this
@@ -2893,6 +2896,12 @@ static int probe_remove_event_call(struct trace_event_call *call)
 	__trace_remove_event_call(call);
 
 	return 0;
+ busy:
+	/* No need to clear the trace now */
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		tr->clear_trace = false;
+	}
+	return -EBUSY;
 }
 
 /* Remove an event_call */
@@ -2972,7 +2981,7 @@ static void trace_module_remove_events(struct module *mod)
 	 * over from this module may be passed to the new module events and
 	 * unexpected results may occur.
 	 */
-	tracing_reset_all_online_cpus();
+	tracing_reset_all_online_cpus_unlocked();
 }
 
 static int trace_module_notify(struct notifier_block *self,

kernel/trace/trace_events_hist.c

@@ -983,7 +983,7 @@ static struct hist_field *find_any_var_ref(struct hist_trigger_data *hist_data,
  * A trigger can define one or more variables.  If any one of them is
  * currently referenced by any other trigger, this function will
  * determine that.
-
+ *
  * Typically used to determine whether or not a trigger can be removed
  * - if there are any references to a trigger's variables, it cannot.
  *
@@ -3226,7 +3226,7 @@ static struct field_var *create_field_var(struct hist_trigger_data *hist_data,
  * events.  However, for convenience, users are allowed to directly
  * specify an event field in an action, which will be automatically
  * converted into a variable on their behalf.
-
+ *
  * This function creates a field variable with the name var_name on
  * the hist trigger currently being defined on the target event.  If
  * subsys_name and event_name are specified, this function simply
@@ -5143,6 +5143,9 @@ static void event_hist_trigger(struct event_trigger_data *data,
 	void *key = NULL;
 	unsigned int i;
 
+	if (unlikely(!rbe))
+		return;
+
 	memset(compound_key, 0, hist_data->key_size);
 
 	for_each_hist_key_field(i, hist_data) {

kernel/trace/trace_events_synth.c

@@ -1425,7 +1425,6 @@ int synth_event_delete(const char *event_name)
 	mutex_unlock(&event_mutex);
 
 	if (mod) {
-		mutex_lock(&trace_types_lock);
 		/*
 		 * It is safest to reset the ring buffer if the module
 		 * being unloaded registered any events that were
@@ -1437,7 +1436,6 @@ int synth_event_delete(const char *event_name)
 		 * occur.
 		 */
 		tracing_reset_all_online_cpus();
-		mutex_unlock(&trace_types_lock);
 	}
 
 	return ret;

kernel/trace/trace_events_user.c

@@ -1100,8 +1100,10 @@ static int user_event_create(const char *raw_command)
 
 	group = current_user_event_group();
 
-	if (!group)
+	if (!group) {
+		kfree(name);
 		return -ENOENT;
+	}
 
 	mutex_lock(&group->reg_mutex);
 

kernel/trace/trace_osnoise.c

@@ -917,7 +917,7 @@ void osnoise_trace_irq_entry(int id)
 void osnoise_trace_irq_exit(int id, const char *desc)
 {
 	struct osnoise_variables *osn_var = this_cpu_osn_var();
-	int duration;
+	s64 duration;
 
 	if (!osn_var->sampling)
 		return;
@@ -1048,7 +1048,7 @@ static void trace_softirq_entry_callback(void *data, unsigned int vec_nr)
 static void trace_softirq_exit_callback(void *data, unsigned int vec_nr)
 {
 	struct osnoise_variables *osn_var = this_cpu_osn_var();
-	int duration;
+	s64 duration;
 
 	if (!osn_var->sampling)
 		return;
@@ -1144,7 +1144,7 @@ thread_entry(struct osnoise_variables *osn_var, struct task_struct *t)
 static void
 thread_exit(struct osnoise_variables *osn_var, struct task_struct *t)
 {
-	int duration;
+	s64 duration;
 
 	if (!osn_var->sampling)
 		return;