projects/linux·blob v3.7-rc4 · refs

110 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/export.h>
18#include <linux/poison.h>
19#include <linux/sched.h>
20#include <linux/spinlock.h>
21#include <linux/kallsyms.h>
22#include <linux/interrupt.h>
23#include <linux/debug_locks.h>
24
25#include "mutex-debug.h"
26
27/*
28 * Must be called with lock->wait_lock held.
29 */
30void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
31{
32 memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
33 waiter->magic = waiter;
34 INIT_LIST_HEAD(&waiter->list);
35}
36
37void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
38{
39 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));
43}
44
45void debug_mutex_free_waiter(struct mutex_waiter *waiter)
46{
47 DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
48 memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
49}
50
51void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
52 struct thread_info *ti)
53{
54 SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
55
56 /* Mark the current thread as blocked on the lock: */
57 ti->task->blocked_on = waiter;
58}
59
60void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
61 struct thread_info *ti)
62{
63 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);
66 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{
74 if (unlikely(!debug_locks))
75 return;
76
77 DEBUG_LOCKS_WARN_ON(lock->magic != lock);
78 DEBUG_LOCKS_WARN_ON(lock->owner != current);
79 DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
80 mutex_clear_owner(lock);
81}
82
83void debug_mutex_init(struct mutex *lock, const char *name,
84 struct lock_class_key *key)
85{
86#ifdef CONFIG_DEBUG_LOCK_ALLOC
87 /*
88 * Make sure we are not reinitializing a held lock:
89 */
90 debug_check_no_locks_freed((void *)lock, sizeof(*lock));
91 lockdep_init_map(&lock->dep_map, name, key, 0);
92#endif
93 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 */
104void mutex_destroy(struct mutex *lock)
105{
106 DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
107 lock->magic = NULL;
108}
109
110EXPORT_SYMBOL_GPL(mutex_destroy);