kernel/backtracetest.c

   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
  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
  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
  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
  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
  66 static void backtrace_test_saved(void)
  67 {
  68         pr_info("Saved backtrace test skipped.\n");
  69 }
  70 #endif
  71
  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
  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>");