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408894ee IM |
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 <mingo@redhat.com> | |
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> | |
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16 | #include <linux/delay.h> |
17 | #include <linux/module.h> | |
a7807a32 | 18 | #include <linux/poison.h> |
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19 | #include <linux/spinlock.h> |
20 | #include <linux/kallsyms.h> | |
21 | #include <linux/interrupt.h> | |
9a11b49a | 22 | #include <linux/debug_locks.h> |
408894ee | 23 | |
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24 | #include "mutex-debug.h" |
25 | ||
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26 | /* |
27 | * Must be called with lock->wait_lock held. | |
28 | */ | |
9a11b49a | 29 | void debug_mutex_set_owner(struct mutex *lock, struct thread_info *new_owner) |
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30 | { |
31 | lock->owner = new_owner; | |
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32 | } |
33 | ||
9a11b49a | 34 | void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter) |
408894ee | 35 | { |
a7807a32 | 36 | memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter)); |
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37 | waiter->magic = waiter; |
38 | INIT_LIST_HEAD(&waiter->list); | |
39 | } | |
40 | ||
41 | void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter) | |
42 | { | |
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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)); | |
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47 | } |
48 | ||
49 | void debug_mutex_free_waiter(struct mutex_waiter *waiter) | |
50 | { | |
9e7f4d45 | 51 | DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list)); |
a7807a32 | 52 | memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter)); |
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53 | } |
54 | ||
55 | void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter, | |
9a11b49a | 56 | struct thread_info *ti) |
408894ee | 57 | { |
9e7f4d45 | 58 | SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock)); |
9a11b49a | 59 | |
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60 | /* Mark the current thread as blocked on the lock: */ |
61 | ti->task->blocked_on = waiter; | |
62 | waiter->lock = lock; | |
63 | } | |
64 | ||
65 | void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter, | |
66 | struct thread_info *ti) | |
67 | { | |
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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); | |
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71 | ti->task->blocked_on = NULL; |
72 | ||
73 | list_del_init(&waiter->list); | |
74 | waiter->task = NULL; | |
75 | } | |
76 | ||
77 | void debug_mutex_unlock(struct mutex *lock) | |
78 | { | |
2ee91f19 IM |
79 | if (unlikely(!debug_locks)) |
80 | return; | |
81 | ||
9a11b49a | 82 | DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info()); |
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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()); | |
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86 | } |
87 | ||
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88 | void debug_mutex_init(struct mutex *lock, const char *name, |
89 | struct lock_class_key *key) | |
408894ee | 90 | { |
ef5d4707 | 91 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
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92 | /* |
93 | * Make sure we are not reinitializing a held lock: | |
94 | */ | |
9a11b49a | 95 | debug_check_no_locks_freed((void *)lock, sizeof(*lock)); |
4dfbb9d8 | 96 | lockdep_init_map(&lock->dep_map, name, key, 0); |
ef5d4707 | 97 | #endif |
408894ee | 98 | lock->owner = NULL; |
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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 | */ | |
7ad5b3a5 | 110 | void mutex_destroy(struct mutex *lock) |
408894ee | 111 | { |
9e7f4d45 | 112 | DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock)); |
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113 | lock->magic = NULL; |
114 | } | |
115 | ||
116 | EXPORT_SYMBOL_GPL(mutex_destroy); |