projects/linux·blob v2.6.25-rc5 · refs

116 lines · 3.0 KiB

1/*
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 <[email protected]>
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>
16#include <linux/delay.h>
17#include <linux/module.h>
18#include <linux/poison.h>
19#include <linux/spinlock.h>
20#include <linux/kallsyms.h>
21#include <linux/interrupt.h>
22#include <linux/debug_locks.h>
23
24#include "mutex-debug.h"
25
26/*
27 * Must be called with lock->wait_lock held.
28 */
29void debug_mutex_set_owner(struct mutex *lock, struct thread_info *new_owner)
30{
31 lock->owner = new_owner;
32}
33
34void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
35{
36 memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
37 waiter->magic = waiter;
38 INIT_LIST_HEAD(&waiter->list);
39}
40
41void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
42{
43 SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
44 DEBUG_LOCKS_WARN_ON(list_empty(&lock->wait_list));
45 DEBUG_LOCKS_WARN_ON(waiter->magic != waiter);
46 DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
47}
48
49void debug_mutex_free_waiter(struct mutex_waiter *waiter)
50{
51 DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
52 memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
53}
54
55void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
56 struct thread_info *ti)
57{
58 SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
59
60 /* Mark the current thread as blocked on the lock: */
61 ti->task->blocked_on = waiter;
62 waiter->lock = lock;
63}
64
65void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
66 struct thread_info *ti)
67{
68 DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
69 DEBUG_LOCKS_WARN_ON(waiter->task != ti->task);
70 DEBUG_LOCKS_WARN_ON(ti->task->blocked_on != waiter);
71 ti->task->blocked_on = NULL;
72
73 list_del_init(&waiter->list);
74 waiter->task = NULL;
75}
76
77void debug_mutex_unlock(struct mutex *lock)
78{
79 if (unlikely(!debug_locks))
80 return;
81
82 DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
83 DEBUG_LOCKS_WARN_ON(lock->magic != lock);
84 DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
85 DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
86}
87
88void debug_mutex_init(struct mutex *lock, const char *name,
89 struct lock_class_key *key)
90{
91#ifdef CONFIG_DEBUG_LOCK_ALLOC
92 /*
93 * Make sure we are not reinitializing a held lock:
94 */
95 debug_check_no_locks_freed((void *)lock, sizeof(*lock));
96 lockdep_init_map(&lock->dep_map, name, key, 0);
97#endif
98 lock->owner = NULL;
99 lock->magic = lock;
100}
101
102/***
103 * mutex_destroy - mark a mutex unusable
104 * @lock: the mutex to be destroyed
105 *
106 * This function marks the mutex uninitialized, and any subsequent
107 * use of the mutex is forbidden. The mutex must not be locked when
108 * this function is called.
109 */
110void mutex_destroy(struct mutex *lock)
111{
112 DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
113 lock->magic = NULL;
114}
115
116EXPORT_SYMBOL_GPL(mutex_destroy);