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 
backtrace_test_bh_workfn(struct work_struct * work)24 static void backtrace_test_bh_workfn(struct work_struct *work)
25 {
26 	dump_stack();
27 }
28 
29 static DECLARE_WORK(backtrace_bh_work, &backtrace_test_bh_workfn);
30 
backtrace_test_bh(void)31 static void backtrace_test_bh(void)
32 {
33 	pr_info("Testing a backtrace from BH context.\n");
34 	pr_info("The following trace is a kernel self test and not a bug!\n");
35 
36 	queue_work(system_bh_wq, &backtrace_bh_work);
37 	flush_work(&backtrace_bh_work);
38 }
39 
40 #ifdef CONFIG_STACKTRACE
backtrace_test_saved(void)41 static void backtrace_test_saved(void)
42 {
43 	unsigned long entries[8];
44 	unsigned int nr_entries;
45 
46 	pr_info("Testing a saved backtrace.\n");
47 	pr_info("The following trace is a kernel self test and not a bug!\n");
48 
49 	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
50 	stack_trace_print(entries, nr_entries, 0);
51 }
52 #else
backtrace_test_saved(void)53 static void backtrace_test_saved(void)
54 {
55 	pr_info("Saved backtrace test skipped.\n");
56 }
57 #endif
58 
backtrace_regression_test(void)59 static int backtrace_regression_test(void)
60 {
61 	pr_info("====[ backtrace testing ]===========\n");
62 
63 	backtrace_test_normal();
64 	backtrace_test_bh();
65 	backtrace_test_saved();
66 
67 	pr_info("====[ end of backtrace testing ]====\n");
68 	return 0;
69 }
70 
exitf(void)71 static void exitf(void)
72 {
73 }
74 
75 module_init(backtrace_regression_test);
76 module_exit(exitf);
77 MODULE_DESCRIPTION("Simple stack backtrace regression test module");
78 MODULE_LICENSE("GPL");
79 MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
80