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Ingo Molnar408894e2006-01-09 15:59:20 -08001/*
2 * kernel/mutex-debug.c
3 *
4 * Debugging code for mutexes
5 *
6 * Started by Ingo Molnar:
7 *
8 * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
9 *
10 * lock debugging, locking tree, deadlock detection started by:
11 *
12 * Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
13 * Released under the General Public License (GPL).
14 */
15#include <linux/mutex.h>
Ingo Molnar408894e2006-01-09 15:59:20 -080016#include <linux/delay.h>
17#include <linux/module.h>
Randy Dunlapa7807a32006-06-27 02:53:54 -070018#include <linux/poison.h>
Alexey Dobriyand43c36d2009-10-07 17:09:06 +040019#include <linux/sched.h>
Ingo Molnar408894e2006-01-09 15:59:20 -080020#include <linux/spinlock.h>
21#include <linux/kallsyms.h>
22#include <linux/interrupt.h>
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070023#include <linux/debug_locks.h>
Ingo Molnar408894e2006-01-09 15:59:20 -080024
Ingo Molnar408894e2006-01-09 15:59:20 -080025#include "mutex-debug.h"
26
27/*
Ingo Molnar408894e2006-01-09 15:59:20 -080028 * Must be called with lock->wait_lock held.
29 */
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070030void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
Ingo Molnar408894e2006-01-09 15:59:20 -080031{
Randy Dunlapa7807a32006-06-27 02:53:54 -070032 memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
Ingo Molnar408894e2006-01-09 15:59:20 -080033 waiter->magic = waiter;
34 INIT_LIST_HEAD(&waiter->list);
35}
36
37void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
38{
Ingo Molnar9e7f4d42006-07-03 00:24:30 -070039 SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
40 DEBUG_LOCKS_WARN_ON(list_empty(&lock->wait_list));
41 DEBUG_LOCKS_WARN_ON(waiter->magic != waiter);
42 DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
Ingo Molnar408894e2006-01-09 15:59:20 -080043}
44
45void debug_mutex_free_waiter(struct mutex_waiter *waiter)
46{
Ingo Molnar9e7f4d42006-07-03 00:24:30 -070047 DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
Randy Dunlapa7807a32006-06-27 02:53:54 -070048 memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
Ingo Molnar408894e2006-01-09 15:59:20 -080049}
50
51void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070052 struct thread_info *ti)
Ingo Molnar408894e2006-01-09 15:59:20 -080053{
Ingo Molnar9e7f4d42006-07-03 00:24:30 -070054 SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070055
Ingo Molnar408894e2006-01-09 15:59:20 -080056 /* Mark the current thread as blocked on the lock: */
57 ti->task->blocked_on = waiter;
Ingo Molnar408894e2006-01-09 15:59:20 -080058}
59
60void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
61 struct thread_info *ti)
62{
Ingo Molnar9e7f4d42006-07-03 00:24:30 -070063 DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
64 DEBUG_LOCKS_WARN_ON(waiter->task != ti->task);
65 DEBUG_LOCKS_WARN_ON(ti->task->blocked_on != waiter);
Ingo Molnar408894e2006-01-09 15:59:20 -080066 ti->task->blocked_on = NULL;
67
68 list_del_init(&waiter->list);
69 waiter->task = NULL;
70}
71
72void debug_mutex_unlock(struct mutex *lock)
73{
Ingo Molnar2ee91f12006-12-06 20:39:32 -080074 if (unlikely(!debug_locks))
75 return;
76
Ingo Molnar9e7f4d42006-07-03 00:24:30 -070077 DEBUG_LOCKS_WARN_ON(lock->magic != lock);
Jeremy Kerr493d3582008-05-14 16:22:58 -070078 DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
Ingo Molnar9e7f4d42006-07-03 00:24:30 -070079 DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
Peter Zijlstra0d66bf62009-01-12 14:01:47 +010080 mutex_clear_owner(lock);
Ingo Molnar408894e2006-01-09 15:59:20 -080081}
82
Ingo Molnaref5d4702006-07-03 00:24:55 -070083void debug_mutex_init(struct mutex *lock, const char *name,
84 struct lock_class_key *key)
Ingo Molnar408894e2006-01-09 15:59:20 -080085{
Ingo Molnaref5d4702006-07-03 00:24:55 -070086#ifdef CONFIG_DEBUG_LOCK_ALLOC
Ingo Molnar408894e2006-01-09 15:59:20 -080087 /*
88 * Make sure we are not reinitializing a held lock:
89 */
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070090 debug_check_no_locks_freed((void *)lock, sizeof(*lock));
Peter Zijlstra4dfbb9d2006-10-11 01:45:14 -040091 lockdep_init_map(&lock->dep_map, name, key, 0);
Ingo Molnaref5d4702006-07-03 00:24:55 -070092#endif
Ingo Molnar408894e2006-01-09 15:59:20 -080093 lock->magic = lock;
94}
95
96/***
97 * mutex_destroy - mark a mutex unusable
98 * @lock: the mutex to be destroyed
99 *
100 * This function marks the mutex uninitialized, and any subsequent
101 * use of the mutex is forbidden. The mutex must not be locked when
102 * this function is called.
103 */
Harvey Harrison7ad5b3a2008-02-08 04:19:53 -0800104void mutex_destroy(struct mutex *lock)
Ingo Molnar408894e2006-01-09 15:59:20 -0800105{
Ingo Molnar9e7f4d42006-07-03 00:24:30 -0700106 DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
Ingo Molnar408894e2006-01-09 15:59:20 -0800107 lock->magic = NULL;
108}
109
110EXPORT_SYMBOL_GPL(mutex_destroy);