sample-trace-array: Remove trace_array 'sample-instance'

Remove trace_array 'sample-instance' if kthread_run fails
in sample_trace_array_init().

Link: https://lkml.kernel.org/r/20200609135200.2206726-1-wangkefeng.wang@huawei.com

Cc: stable@vger.kernel.org
Fixes: 89ed42495e ("tracing: Sample module to demonstrate kernel access to Ftrace instances.")
Reviewed-by: Divya Indi <divya.indi@oracle.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

samples/ftrace/sample-trace-array.c

@@ -115,8 +115,12 @@ static int __init sample_trace_array_init(void)
 	trace_printk_init_buffers();
 
 	simple_tsk = kthread_run(simple_thread, NULL, "sample-instance");
-	if (IS_ERR(simple_tsk))
+	if (IS_ERR(simple_tsk)) {
+		trace_array_put(tr);
+		trace_array_destroy(tr);
 		return -1;
+	}
+
 	return 0;
 }