diff --git a/[refs] b/[refs]
index 9424cf037b4d..6cbb75e89e27 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 5d1a03dc541dc6672e60e57249ed22f40654ca47
+refs/heads/master: 05ce5818adee8f8efd0a5ca0d900a6789012516b
diff --git a/trunk/kernel/trace/ftrace.c b/trunk/kernel/trace/ftrace.c
index 7847806eefef..c81a759fbf76 100644
--- a/trunk/kernel/trace/ftrace.c
+++ b/trunk/kernel/trace/ftrace.c
@@ -2643,6 +2643,12 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 
 	mutex_lock(&ftrace_lock);
 
+	/* we currently allow only one tracer registered at a time */
+	if (atomic_read(&ftrace_graph_active)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
 	ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
 	register_pm_notifier(&ftrace_suspend_notifier);