diff options
-rw-r--r-- | kernel/trace/ftrace.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 7847806eefef..c81a759fbf76 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c | |||
@@ -2643,6 +2643,12 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc, | |||
2643 | 2643 | ||
2644 | mutex_lock(&ftrace_lock); | 2644 | mutex_lock(&ftrace_lock); |
2645 | 2645 | ||
2646 | /* we currently allow only one tracer registered at a time */ | ||
2647 | if (atomic_read(&ftrace_graph_active)) { | ||
2648 | ret = -EBUSY; | ||
2649 | goto out; | ||
2650 | } | ||
2651 | |||
2646 | ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call; | 2652 | ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call; |
2647 | register_pm_notifier(&ftrace_suspend_notifier); | 2653 | register_pm_notifier(&ftrace_suspend_notifier); |
2648 | 2654 | ||