1 files changed, 33 insertions, 8 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 1d18315..189b09b 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -78,7 +78,7 @@ EXPORT_SYMBOL_GPL(trace_define_field);
 	if (ret)							\
 		return ret;
 
-int trace_define_common_fields(struct ftrace_event_call *call)
+static int trace_define_common_fields(struct ftrace_event_call *call)
 {
 	int ret;
 	struct trace_entry ent;
@@ -91,7 +91,6 @@ int trace_define_common_fields(struct ftrace_event_call *call)
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(trace_define_common_fields);
 
 void trace_destroy_fields(struct ftrace_event_call *call)
 {
@@ -105,9 +104,25 @@ void trace_destroy_fields(struct ftrace_event_call *call)
 	}
 }
 
-static void ftrace_event_enable_disable(struct ftrace_event_call *call,
+int trace_event_raw_init(struct ftrace_event_call *call)
+{
+	int id;
+
+	id = register_ftrace_event(call->event);
+	if (!id)
+		return -ENODEV;
+	call->id = id;
+	INIT_LIST_HEAD(&call->fields);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(trace_event_raw_init);
+
+static int ftrace_event_enable_disable(struct ftrace_event_call *call,
 					int enable)
 {
+	int ret = 0;
+
 	switch (enable) {
 	case 0:
 		if (call->enabled) {
@@ -118,12 +133,20 @@ static void ftrace_event_enable_disable(struct ftrace_event_call *call,
 		break;
 	case 1:
 		if (!call->enabled) {
-			call->enabled = 1;
 			tracing_start_cmdline_record();
-			call->regfunc(call);
+			ret = call->regfunc(call);
+			if (ret) {
+				tracing_stop_cmdline_record();
+				pr_info("event trace: Could not enable event "
+					"%s\n", call->name);
+				break;
+			}
+			call->enabled = 1;
 		}
 		break;
 	}
+
+	return ret;
 }
 
 static void ftrace_clear_events(void)
@@ -402,7 +425,7 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 	case 0:
 	case 1:
 		mutex_lock(&event_mutex);
-		ftrace_event_enable_disable(call, val);
+		ret = ftrace_event_enable_disable(call, val);
 		mutex_unlock(&event_mutex);
 		break;
 
@@ -412,7 +435,7 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 
 	*ppos += cnt;
 
-	return cnt;
+	return ret ? ret : cnt;
 }
 
 static ssize_t
@@ -913,7 +936,9 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
 		 		  id);
 
 	if (call->define_fields) {
-		ret = call->define_fields(call);
+		ret = trace_define_common_fields(call);
+		if (!ret)
+			ret = call->define_fields(call);
 		if (ret < 0) {
 			pr_warning("Could not initialize trace point"
 				   " events/%s\n", call->name);