From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The start function of the hwlat tracer should never be called when the hwlat
thread already exists. If it is called, do a WARN_ON().

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_hwlat.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index 2d9d36dd5fe7..688e48be7bb5 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -354,7 +354,7 @@ static int start_kthread(struct trace_array *tr)
 	struct task_struct *kthread;
 	int next_cpu;
 
-	if (hwlat_kthread)
+	if (WARN_ON(hwlat_kthread))
 		return 0;
 
 	/* Just pick the first CPU on first iteration */
-- 
2.18.0