1// SPDX-License-Identifier: GPL-2.0-only
  2#include <linux/module.h>
  3#include <linux/kthread.h>
  4
  5/*
  6 * Any file that uses trace points, must include the header.
  7 * But only one file, must include the header by defining
  8 * CREATE_TRACE_POINTS first.  This will make the C code that
  9 * creates the handles for the trace points.
 10 */
 11#define CREATE_TRACE_POINTS
 12#include "trace-events-sample.h"
 13
 14static const char *random_strings[] = {
 15	"Mother Goose",
 16	"Snoopy",
 17	"Gandalf",
 18	"Frodo",
 19	"One ring to rule them all"
 20};
 21
 22static void simple_thread_func(int cnt)
 23{
 24	int array[6];
 25	int len = cnt % 5;
 26	int i;
 27
 28	set_current_state(TASK_INTERRUPTIBLE);
 29	schedule_timeout(HZ);
 30
 31	for (i = 0; i < len; i++)
 32		array[i] = i + 1;
 33	array[i] = 0;
 34
 35	/* Silly tracepoints */
 36	trace_foo_bar("hello", cnt, array, random_strings[len],
 37		      current->cpus_ptr);
 38
 39	trace_foo_with_template_simple("HELLO", cnt);
 40
 41	trace_foo_bar_with_cond("Some times print", cnt);
 42
 43	trace_foo_with_template_cond("prints other times", cnt);
 44
 45	trace_foo_with_template_print("I have to be different", cnt);
 46}
 47
 48static int simple_thread(void *arg)
 49{
 50	int cnt = 0;
 51
 52	while (!kthread_should_stop())
 53		simple_thread_func(cnt++);
 54
 55	return 0;
 56}
 57
 58static struct task_struct *simple_tsk;
 59static struct task_struct *simple_tsk_fn;
 60
 61static void simple_thread_func_fn(int cnt)
 62{
 63	set_current_state(TASK_INTERRUPTIBLE);
 64	schedule_timeout(HZ);
 65
 66	/* More silly tracepoints */
 67	trace_foo_bar_with_fn("Look at me", cnt);
 68	trace_foo_with_template_fn("Look at me too", cnt);
 69}
 70
 71static int simple_thread_fn(void *arg)
 72{
 73	int cnt = 0;
 74
 75	while (!kthread_should_stop())
 76		simple_thread_func_fn(cnt++);
 77
 78	return 0;
 79}
 80
 81static DEFINE_MUTEX(thread_mutex);
 82static int simple_thread_cnt;
 83
 84int foo_bar_reg(void)
 85{
 86	mutex_lock(&thread_mutex);
 87	if (simple_thread_cnt++)
 88		goto out;
 89
 90	pr_info("Starting thread for foo_bar_fn\n");
 91	/*
 92	 * We shouldn't be able to start a trace when the module is
 93	 * unloading (there's other locks to prevent that). But
 94	 * for consistency sake, we still take the thread_mutex.
 95	 */
 96	simple_tsk_fn = kthread_run(simple_thread_fn, NULL, "event-sample-fn");
 97 out:
 98	mutex_unlock(&thread_mutex);
 99	return 0;
100}
101
102void foo_bar_unreg(void)
103{
104	mutex_lock(&thread_mutex);
105	if (--simple_thread_cnt)
106		goto out;
107
108	pr_info("Killing thread for foo_bar_fn\n");
109	if (simple_tsk_fn)
110		kthread_stop(simple_tsk_fn);
111	simple_tsk_fn = NULL;
112 out:
113	mutex_unlock(&thread_mutex);
114}
115
116static int __init trace_event_init(void)
117{
118	simple_tsk = kthread_run(simple_thread, NULL, "event-sample");
119	if (IS_ERR(simple_tsk))
120		return -1;
121
122	return 0;
123}
124
125static void __exit trace_event_exit(void)
126{
127	kthread_stop(simple_tsk);
128	mutex_lock(&thread_mutex);
129	if (simple_tsk_fn)
130		kthread_stop(simple_tsk_fn);
131	simple_tsk_fn = NULL;
132	mutex_unlock(&thread_mutex);
133}
134
135module_init(trace_event_init);
136module_exit(trace_event_exit);
137
138MODULE_AUTHOR("Steven Rostedt");
139MODULE_DESCRIPTION("trace-events-sample");
140MODULE_LICENSE("GPL");

 
 1#include <linux/module.h>
 2#include <linux/kthread.h>
 3
 4/*
 5 * Any file that uses trace points, must include the header.
 6 * But only one file, must include the header by defining
 7 * CREATE_TRACE_POINTS first.  This will make the C code that
 8 * creates the handles for the trace points.
 9 */
10#define CREATE_TRACE_POINTS
11#include "trace-events-sample.h"
12
 
 
 
 
 
 
 
13
14static void simple_thread_func(int cnt)
15{
 
 
 
 
16	set_current_state(TASK_INTERRUPTIBLE);
17	schedule_timeout(HZ);
18	trace_foo_bar("hello", cnt);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
19}
20
21static int simple_thread(void *arg)
22{
23	int cnt = 0;
24
25	while (!kthread_should_stop())
26		simple_thread_func(cnt++);
27
28	return 0;
29}
30
31static struct task_struct *simple_tsk;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
32
33static int __init trace_event_init(void)
34{
35	simple_tsk = kthread_run(simple_thread, NULL, "event-sample");
36	if (IS_ERR(simple_tsk))
37		return -1;
38
39	return 0;
40}
41
42static void __exit trace_event_exit(void)
43{
44	kthread_stop(simple_tsk);
 
 
 
 
 
45}
46
47module_init(trace_event_init);
48module_exit(trace_event_exit);
49
50MODULE_AUTHOR("Steven Rostedt");
51MODULE_DESCRIPTION("trace-events-sample");
52MODULE_LICENSE("GPL");