kernel/backtracetest.c

   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
  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 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
  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
  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
  53 static void backtrace_test_saved(void)
  54 {
  55         pr_info("Saved backtrace test skipped.\n");
  56 }
  57 #endif
  58
  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
  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>");