tracing: Do a WARN_ON() if start_thread() in hwlat is called when thread exists

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>

1 files changed, 1 insertions, 1 deletions

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 */