1 /*
2  * Simple stack backtrace regression test module
3  *
4  * (C) Copyright 2008 Intel Corporation
5  * Author: Arjan van de Ven <arjan@linux.intel.com>
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License
9  * as published by the Free Software Foundation; version 2
10  * of the License.
11  */
12 
13 #include <linux/completion.h>
14 #include <linux/delay.h>
15 #include <linux/interrupt.h>
16 #include <linux/module.h>
17 #include <linux/sched.h>
18 #include <linux/stacktrace.h>
19 
backtrace_test_normal(void)20 static void backtrace_test_normal(void)
21 {
22 	pr_info("Testing a backtrace from process context.\n");
23 	pr_info("The following trace is a kernel self test and not a bug!\n");
24 
25 	dump_stack();
26 }
27 
28 static DECLARE_COMPLETION(backtrace_work);
29 
backtrace_test_irq_callback(unsigned long data)30 static void backtrace_test_irq_callback(unsigned long data)
31 {
32 	dump_stack();
33 	complete(&backtrace_work);
34 }
35 
36 static DECLARE_TASKLET(backtrace_tasklet, &backtrace_test_irq_callback, 0);
37 
backtrace_test_irq(void)38 static void backtrace_test_irq(void)
39 {
40 	pr_info("Testing a backtrace from irq context.\n");
41 	pr_info("The following trace is a kernel self test and not a bug!\n");
42 
43 	init_completion(&backtrace_work);
44 	tasklet_schedule(&backtrace_tasklet);
45 	wait_for_completion(&backtrace_work);
46 }
47 
48 #ifdef CONFIG_STACKTRACE
backtrace_test_saved(void)49 static void backtrace_test_saved(void)
50 {
51 	struct stack_trace trace;
52 	unsigned long entries[8];
53 
54 	pr_info("Testing a saved backtrace.\n");
55 	pr_info("The following trace is a kernel self test and not a bug!\n");
56 
57 	trace.nr_entries = 0;
58 	trace.max_entries = ARRAY_SIZE(entries);
59 	trace.entries = entries;
60 	trace.skip = 0;
61 
62 	save_stack_trace(&trace);
63 	print_stack_trace(&trace, 0);
64 }
65 #else
backtrace_test_saved(void)66 static void backtrace_test_saved(void)
67 {
68 	pr_info("Saved backtrace test skipped.\n");
69 }
70 #endif
71 
backtrace_regression_test(void)72 static int backtrace_regression_test(void)
73 {
74 	pr_info("====[ backtrace testing ]===========\n");
75 
76 	backtrace_test_normal();
77 	backtrace_test_irq();
78 	backtrace_test_saved();
79 
80 	pr_info("====[ end of backtrace testing ]====\n");
81 	return 0;
82 }
83 
exitf(void)84 static void exitf(void)
85 {
86 }
87 
88 module_init(backtrace_regression_test);
89 module_exit(exitf);
90 MODULE_LICENSE("GPL");
91 MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
92