projects/linux·blob v6.17 · refs

119 lines · 3.1 KiB

1/*
2 * Debugging code for mutexes
3 *
4 * Started by Ingo Molnar:
5 *
6 * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <[email protected]>
7 *
8 * lock debugging, locking tree, deadlock detection started by:
9 *
10 * Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
11 * Released under the General Public License (GPL).
12 */
13#include <linux/mutex.h>
14#include <linux/delay.h>
15#include <linux/device.h>
16#include <linux/export.h>
17#include <linux/poison.h>
18#include <linux/sched.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.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 waiter->ww_ctx = MUTEX_POISON_WW_CTX;
35}
36
37void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
38{
39 lockdep_assert_held(&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 task_struct *task)
53{
54 lockdep_assert_held(&lock->wait_lock);
55
56 /* Current thread can't be already blocked (since it's executing!) */
57 DEBUG_LOCKS_WARN_ON(__get_task_blocked_on(task));
58}
59
60void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
61 struct task_struct *task)
62{
63 struct mutex *blocked_on = __get_task_blocked_on(task);
64
65 DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
66 DEBUG_LOCKS_WARN_ON(waiter->task != task);
67 DEBUG_LOCKS_WARN_ON(blocked_on && blocked_on != lock);
68
69 INIT_LIST_HEAD(&waiter->list);
70 waiter->task = NULL;
71}
72
73void debug_mutex_unlock(struct mutex *lock)
74{
75 if (likely(debug_locks)) {
76 DEBUG_LOCKS_WARN_ON(lock->magic != lock);
77 DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
78 }
79}
80
81void debug_mutex_init(struct mutex *lock, const char *name,
82 struct lock_class_key *key)
83{
84#ifdef CONFIG_DEBUG_LOCK_ALLOC
85 /*
86 * Make sure we are not reinitializing a held lock:
87 */
88 debug_check_no_locks_freed((void *)lock, sizeof(*lock));
89 lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_SLEEP);
90#endif
91 lock->magic = lock;
92}
93
94static void devm_mutex_release(void *res)
95{
96 mutex_destroy(res);
97}
98
99int __devm_mutex_init(struct device *dev, struct mutex *lock)
100{
101 return devm_add_action_or_reset(dev, devm_mutex_release, lock);
102}
103EXPORT_SYMBOL_GPL(__devm_mutex_init);
104
105/***
106 * mutex_destroy - mark a mutex unusable
107 * @lock: the mutex to be destroyed
108 *
109 * This function marks the mutex uninitialized, and any subsequent
110 * use of the mutex is forbidden. The mutex must not be locked when
111 * this function is called.
112 */
113void mutex_destroy(struct mutex *lock)
114{
115 DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
116 lock->magic = NULL;
117}
118
119EXPORT_SYMBOL_GPL(mutex_destroy);