From: Steven Rostedt (VMware) <rostedt@goodmis.org>
Date: Wed, 1 Aug 2018 20:06:02 +0000 (-0400)
Subject: tracing: Do a WARN_ON() if start_thread() in hwlat is called when thread exists
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=978defee11a5;p=linux.git

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>
---

diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index 2d9d36dd5fe77..688e48be7bb51 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 */