---

yaml --- r: 141032 b: refs/heads/master c: 05ce581 h: refs/heads/master v: v3
git-mirror · Mar 24, 2009 · fb4ff6a · fb4ff6a
1 parent 3969525
commit fb4ff6a
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Showing 2 changed files with 7 additions and 1 deletion.
diff --git 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
@@ -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);