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-rw-r--r--kernel/trace/trace_hwlat.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index d7c8e4ec3d9d..1e6db9cbe4dc 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
/*
* trace_hwlatdetect.c - A simple Hardware Latency detector.
*
@@ -35,9 +36,6 @@
*
* Includes useful feedback from Clark Williams <clark@redhat.com>
*
- * This file is licensed under the terms of the GNU General Public
- * License version 2. This program is licensed "as is" without any
- * warranty of any kind, whether express or implied.
*/
#include <linux/kthread.h>
#include <linux/tracefs.h>
@@ -354,6 +352,9 @@ static int start_kthread(struct trace_array *tr)
struct task_struct *kthread;
int next_cpu;
+ if (WARN_ON(hwlat_kthread))
+ return 0;
+
/* Just pick the first CPU on first iteration */
current_mask = &save_cpumask;
get_online_cpus();