ftrace: Fix three small bugs

index 217207a..9e82551 100644
@@ -252,6 +252,9 @@ static inline struct trace_array *top_trace_array(void)
 {
 	struct trace_array *tr;
 
+	if (list_empty(ftrace_trace_arrays.prev))
+		return NULL;
+
 	tr = list_entry(ftrace_trace_arrays.prev,
 			typeof(*tr), list);
 	WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));

index 3ddfd8f..1349870 100644
@@ -574,6 +574,9 @@ int trace_set_clr_event(const char *system, const char *event, int set)
 {
 	struct trace_array *tr = top_trace_array();
 
+	if (!tr)
+		return -ENODEV;
+
 	return __ftrace_set_clr_event(tr, NULL, system, event, set);
 }
 EXPORT_SYMBOL_GPL(trace_set_clr_event);

@@ -2065,6 +2068,9 @@ event_enable_func(struct ftrace_hash *hash,
 	bool enable;
 	int ret;
 
+	if (!tr)
+		return -ENODEV;
+
 	/* hash funcs only work with set_ftrace_filter */
 	if (!enabled || !param)
 		return -EINVAL;

@@ -2396,6 +2402,9 @@ static __init int event_trace_enable(void)
 	char *token;
 	int ret;
 
+	if (!tr)
+		return -ENODEV;
+
 	for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
 
 		call = *iter;

@@ -2442,6 +2451,8 @@ static __init int event_trace_init(void)
 	int ret;
 
 	tr = top_trace_array();
+	if (!tr)
+		return -ENODEV;
 
 	d_tracer = tracing_init_dentry();
 	if (!d_tracer)

@@ -2535,6 +2546,8 @@ static __init void event_trace_self_tests(void)
 	int ret;
 
 	tr = top_trace_array();
+	if (!tr)
+		return -ENODEV;
 
 	pr_info("Running tests on trace events:\n");
 

index 1349870..f99e0b3 100644
@@ -2547,7 +2547,7 @@ static __init void event_trace_self_tests(void)
 
 	tr = top_trace_array();
 	if (!tr)
-		return -ENODEV;
+		return;
 
 	pr_info("Running tests on trace events:\n");
 

index 903ae28..ef2fba1 100644
@@ -1377,6 +1377,9 @@ static __init int kprobe_trace_self_tests_init(void)
 	struct trace_kprobe *tk;
 	struct ftrace_event_file *file;
 
+	if (tracing_is_disabled())
+		return -ENODEV;
+
 	target = kprobe_trace_selftest_target;
 
 	pr_info("Testing kprobe tracing: ");

index 473eb68..bbd86d2 100644
@@ -6277,7 +6277,7 @@ static int new_instance_create(const char *name)
 		goto out_free_tr;
 
 	if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
-		goto out_free_tr;
+		goto out_free_tr_name;
 
 	cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
 

@@ -6291,16 +6291,16 @@ static int new_instance_create(const char *name)
 	INIT_LIST_HEAD(&tr->events);
 
 	if (allocate_trace_buffers(tr, trace_buf_size) < 0)
-		goto out_free_tr;
+		goto out_free_cpumask_var;
 
 	tr->dir = debugfs_create_dir(name, trace_instance_dir);
 	if (!tr->dir)
-		goto out_free_tr;
+		goto out_free_trace_buffers;
 
 	ret = event_trace_add_tracer(tr->dir, tr);
 	if (ret) {
 		debugfs_remove_recursive(tr->dir);
-		goto out_free_tr;
+		goto out_free_trace_buffers;
 	}
 
 	init_tracer_debugfs(tr, tr->dir);

@@ -6311,18 +6311,23 @@ static int new_instance_create(const char *name)
 
 	return 0;
 
- out_free_tr:
-	if (tr->trace_buffer.buffer)
-		ring_buffer_free(tr->trace_buffer.buffer);
+ out_free_trace_buffers:
+	ring_buffer_free(tr->trace_buffer.buffer);
+	free_percpu(tr->trace_buffer.data);
+#ifdef CONFIG_TRACER_MAX_TRACE
+	ring_buffer_free(tr->max_buffer.buffer);
+	free_percpu(tr->max_buffer.data);
+#endif
+ out_free_cpumask_var:
 	free_cpumask_var(tr->tracing_cpumask);
+ out_free_tr_name:
 	kfree(tr->name);
+ out_free_tr:
 	kfree(tr);
-
  out_unlock:
 	mutex_unlock(&trace_types_lock);
 
 	return ret;
-
 }
 
 static int instance_delete(const char *name)

index e29edee..26cfff3 100644
@@ -6232,6 +6232,25 @@ static int allocate_trace_buffers(struct trace_array *tr, int size)
 	return 0;
 }
 
+static void free_trace_buffers(struct trace_array *tr)
+{
+	if (!tr)
+		return;
+
+	if (tr->trace_buffer.buffer) {
+		ring_buffer_free(tr->trace_buffer.buffer);
+		tr->trace_buffer.buffer = NULL;
+		free_percpu(tr->trace_buffer.data);
+	}
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (tr->max_buffer.buffer) {
+		ring_buffer_free(tr->max_buffer.buffer);
+		tr->max_buffer.buffer = NULL;
+	}
+#endif
+}
+
 static int new_instance_create(const char *name)
 {
 	struct trace_array *tr;

@@ -6290,8 +6309,7 @@ static int new_instance_create(const char *name)
 	return 0;
 
  out_free_tr:
-	if (tr->trace_buffer.buffer)
-		ring_buffer_free(tr->trace_buffer.buffer);
+	free_trace_buffers(tr);
 	free_cpumask_var(tr->tracing_cpumask);
 	kfree(tr->name);
 	kfree(tr);