1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Simple stack backtrace regression test module
4  *
5  * (C) Copyright 2008 Intel Corporation
6  * Author: Arjan van de Ven <arjan@linux.intel.com>
7  */
8 
9 #include <linux/completion.h>
10 #include <linux/delay.h>
11 #include <linux/interrupt.h>
12 #include <linux/module.h>
13 #include <linux/sched.h>
14 #include <linux/stacktrace.h>
15 
backtrace_test_normal(void)16 static void backtrace_test_normal(void)
17 {
18 	pr_info("Testing a backtrace from process context.\n");
19 	pr_info("The following trace is a kernel self test and not a bug!\n");
20 
21 	dump_stack();
22 }
23 
24 static DECLARE_COMPLETION(backtrace_work);
25 
backtrace_test_irq_callback(unsigned long data)26 static void backtrace_test_irq_callback(unsigned long data)
27 {
28 	dump_stack();
29 	complete(&backtrace_work);
30 }
31 
32 static DECLARE_TASKLET(backtrace_tasklet, &backtrace_test_irq_callback, 0);
33 
backtrace_test_irq(void)34 static void backtrace_test_irq(void)
35 {
36 	pr_info("Testing a backtrace from irq context.\n");
37 	pr_info("The following trace is a kernel self test and not a bug!\n");
38 
39 	init_completion(&backtrace_work);
40 	tasklet_schedule(&backtrace_tasklet);
41 	wait_for_completion(&backtrace_work);
42 }
43 
44 #ifdef CONFIG_STACKTRACE
backtrace_test_saved(void)45 static void backtrace_test_saved(void)
46 {
47 	unsigned long entries[8];
48 	unsigned int nr_entries;
49 
50 	pr_info("Testing a saved backtrace.\n");
51 	pr_info("The following trace is a kernel self test and not a bug!\n");
52 
53 	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
54 	stack_trace_print(entries, nr_entries, 0);
55 }
56 #else
backtrace_test_saved(void)57 static void backtrace_test_saved(void)
58 {
59 	pr_info("Saved backtrace test skipped.\n");
60 }
61 #endif
62 
backtrace_regression_test(void)63 static int backtrace_regression_test(void)
64 {
65 	pr_info("====[ backtrace testing ]===========\n");
66 
67 	backtrace_test_normal();
68 	backtrace_test_irq();
69 	backtrace_test_saved();
70 
71 	pr_info("====[ end of backtrace testing ]====\n");
72 	return 0;
73 }
74 
exitf(void)75 static void exitf(void)
76 {
77 }
78 
79 module_init(backtrace_regression_test);
80 module_exit(exitf);
81 MODULE_LICENSE("GPL");
82 MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
83