projects/linux·blob v7.2 · refs

108 lines · 2.7 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(!lock->first_waiter);
41 DEBUG_LOCKS_WARN_ON(waiter->magic != waiter);
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 task_struct *task)
52{
53 lockdep_assert_held(&lock->wait_lock);
54
55 /* Current thread can't be already blocked (since it's executing!) */
56 DEBUG_LOCKS_WARN_ON(get_task_blocked_on(task));
57}
58
59void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
60 struct task_struct *task)
61{
62 struct mutex *blocked_on = get_task_blocked_on(task);
63
64 DEBUG_LOCKS_WARN_ON(waiter->task != task);
65 DEBUG_LOCKS_WARN_ON(blocked_on && blocked_on != lock);
66
67 INIT_LIST_HEAD(&waiter->list);
68 waiter->task = NULL;
69}
70
71void debug_mutex_unlock(struct mutex *lock)
72{
73 if (likely(debug_locks)) {
74 DEBUG_LOCKS_WARN_ON(lock->magic != lock);
75 }
76}
77
78void debug_mutex_init(struct mutex *lock)
79{
80 lock->magic = lock;
81}
82
83static void devm_mutex_release(void *res)
84{
85 mutex_destroy(res);
86}
87
88int __devm_mutex_init(struct device *dev, struct mutex *lock)
89{
90 return devm_add_action_or_reset(dev, devm_mutex_release, lock);
91}
92EXPORT_SYMBOL_GPL(__devm_mutex_init);
93
94/***
95 * mutex_destroy - mark a mutex unusable
96 * @lock: the mutex to be destroyed
97 *
98 * This function marks the mutex uninitialized, and any subsequent
99 * use of the mutex is forbidden. The mutex must not be locked when
100 * this function is called.
101 */
102void mutex_destroy(struct mutex *lock)
103{
104 DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
105 lock->magic = NULL;
106}
107
108EXPORT_SYMBOL_GPL(mutex_destroy);