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Ingo Molnar408894e2006-01-09 15:59:20 -08001/*
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>
Ingo Molnar408894e2006-01-09 15:59:20 -080016#include <linux/delay.h>
17#include <linux/module.h>
Randy Dunlapa7807a32006-06-27 02:53:54 -070018#include <linux/poison.h>
Ingo Molnar408894e2006-01-09 15:59:20 -080019#include <linux/spinlock.h>
20#include <linux/kallsyms.h>
21#include <linux/interrupt.h>
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070022#include <linux/debug_locks.h>
Ingo Molnar408894e2006-01-09 15:59:20 -080023
Ingo Molnar408894e2006-01-09 15:59:20 -080024#include "mutex-debug.h"
25
26/*
Ingo Molnar408894e2006-01-09 15:59:20 -080027 * Must be called with lock->wait_lock held.
28 */
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070029void debug_mutex_set_owner(struct mutex *lock, struct thread_info *new_owner)
Ingo Molnar408894e2006-01-09 15:59:20 -080030{
31 lock->owner = new_owner;
Ingo Molnar408894e2006-01-09 15:59:20 -080032}
33
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070034void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
Ingo Molnar408894e2006-01-09 15:59:20 -080035{
Randy Dunlapa7807a32006-06-27 02:53:54 -070036 memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
Ingo Molnar408894e2006-01-09 15:59:20 -080037 waiter->magic = waiter;
38 INIT_LIST_HEAD(&waiter->list);
39}
40
41void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
42{
Ingo Molnar9e7f4d42006-07-03 00:24:30 -070043 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));
Ingo Molnar408894e2006-01-09 15:59:20 -080047}
48
49void debug_mutex_free_waiter(struct mutex_waiter *waiter)
50{
Ingo Molnar9e7f4d42006-07-03 00:24:30 -070051 DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
Randy Dunlapa7807a32006-06-27 02:53:54 -070052 memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
Ingo Molnar408894e2006-01-09 15:59:20 -080053}
54
55void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070056 struct thread_info *ti)
Ingo Molnar408894e2006-01-09 15:59:20 -080057{
Ingo Molnar9e7f4d42006-07-03 00:24:30 -070058 SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070059
Ingo Molnar408894e2006-01-09 15:59:20 -080060 /* Mark the current thread as blocked on the lock: */
61 ti->task->blocked_on = waiter;
62 waiter->lock = lock;
63}
64
65void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
66 struct thread_info *ti)
67{
Ingo Molnar9e7f4d42006-07-03 00:24:30 -070068 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);
Ingo Molnar408894e2006-01-09 15:59:20 -080071 ti->task->blocked_on = NULL;
72
73 list_del_init(&waiter->list);
74 waiter->task = NULL;
75}
76
77void debug_mutex_unlock(struct mutex *lock)
78{
Ingo Molnar2ee91f12006-12-06 20:39:32 -080079 if (unlikely(!debug_locks))
80 return;
81
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070082 DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
Ingo Molnar9e7f4d42006-07-03 00:24:30 -070083 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());
Ingo Molnar408894e2006-01-09 15:59:20 -080086}
87
Ingo Molnaref5d4702006-07-03 00:24:55 -070088void debug_mutex_init(struct mutex *lock, const char *name,
89 struct lock_class_key *key)
Ingo Molnar408894e2006-01-09 15:59:20 -080090{
Ingo Molnaref5d4702006-07-03 00:24:55 -070091#ifdef CONFIG_DEBUG_LOCK_ALLOC
Ingo Molnar408894e2006-01-09 15:59:20 -080092 /*
93 * Make sure we are not reinitializing a held lock:
94 */
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070095 debug_check_no_locks_freed((void *)lock, sizeof(*lock));
Peter Zijlstra4dfbb9d2006-10-11 01:45:14 -040096 lockdep_init_map(&lock->dep_map, name, key, 0);
Ingo Molnaref5d4702006-07-03 00:24:55 -070097#endif
Ingo Molnar408894e2006-01-09 15:59:20 -080098 lock->owner = NULL;
Ingo Molnar408894e2006-01-09 15:59:20 -080099 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 */
110void fastcall mutex_destroy(struct mutex *lock)
111{
Ingo Molnar9e7f4d42006-07-03 00:24:30 -0700112 DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
Ingo Molnar408894e2006-01-09 15:59:20 -0800113 lock->magic = NULL;
114}
115
116EXPORT_SYMBOL_GPL(mutex_destroy);