projects/linux·blob v2.6.30-rc4 · refs

109 lines · 2.9 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_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
30{
31 memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
32 waiter->magic = waiter;
33 INIT_LIST_HEAD(&waiter->list);
34}
35
36void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
37{
38 SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
39 DEBUG_LOCKS_WARN_ON(list_empty(&lock->wait_list));
40 DEBUG_LOCKS_WARN_ON(waiter->magic != waiter);
41 DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
42}
43
44void debug_mutex_free_waiter(struct mutex_waiter *waiter)
45{
46 DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
47 memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
48}
49
50void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
51 struct thread_info *ti)
52{
53 SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
54
55 /* Mark the current thread as blocked on the lock: */
56 ti->task->blocked_on = waiter;
57}
58
59void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
60 struct thread_info *ti)
61{
62 DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
63 DEBUG_LOCKS_WARN_ON(waiter->task != ti->task);
64 DEBUG_LOCKS_WARN_ON(ti->task->blocked_on != waiter);
65 ti->task->blocked_on = NULL;
66
67 list_del_init(&waiter->list);
68 waiter->task = NULL;
69}
70
71void debug_mutex_unlock(struct mutex *lock)
72{
73 if (unlikely(!debug_locks))
74 return;
75
76 DEBUG_LOCKS_WARN_ON(lock->magic != lock);
77 DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
78 DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
79 mutex_clear_owner(lock);
80}
81
82void debug_mutex_init(struct mutex *lock, const char *name,
83 struct lock_class_key *key)
84{
85#ifdef CONFIG_DEBUG_LOCK_ALLOC
86 /*
87 * Make sure we are not reinitializing a held lock:
88 */
89 debug_check_no_locks_freed((void *)lock, sizeof(*lock));
90 lockdep_init_map(&lock->dep_map, name, key, 0);
91#endif
92 lock->magic = lock;
93}
94
95/***
96 * mutex_destroy - mark a mutex unusable
97 * @lock: the mutex to be destroyed
98 *
99 * This function marks the mutex uninitialized, and any subsequent
100 * use of the mutex is forbidden. The mutex must not be locked when
101 * this function is called.
102 */
103void mutex_destroy(struct mutex *lock)
104{
105 DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
106 lock->magic = NULL;
107}
108
109EXPORT_SYMBOL_GPL(mutex_destroy);