4 * Debugging code for mutexes
6 * Started by Ingo Molnar:
8 * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
10 * lock debugging, locking tree, deadlock detection started by:
12 * Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
13 * Released under the General Public License (GPL).
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>
25 #include "mutex-debug.h"
28 * Must be called with lock->wait_lock held.
30 void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
32 memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
33 waiter->magic = waiter;
34 INIT_LIST_HEAD(&waiter->list);
37 void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
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));
45 void debug_mutex_free_waiter(struct mutex_waiter *waiter)
47 DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
48 memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
51 void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
52 struct task_struct *task)
54 lockdep_assert_held(&lock->wait_lock);
56 /* Mark the current thread as blocked on the lock: */
57 task->blocked_on = waiter;
60 void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
61 struct task_struct *task)
63 DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
64 DEBUG_LOCKS_WARN_ON(waiter->task != task);
65 DEBUG_LOCKS_WARN_ON(task->blocked_on != waiter);
66 task->blocked_on = NULL;
68 INIT_LIST_HEAD(&waiter->list);
72 void debug_mutex_unlock(struct mutex *lock)
74 if (likely(debug_locks)) {
75 DEBUG_LOCKS_WARN_ON(lock->magic != lock);
76 DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
80 void debug_mutex_init(struct mutex *lock, const char *name,
81 struct lock_class_key *key)
83 #ifdef CONFIG_DEBUG_LOCK_ALLOC
85 * Make sure we are not reinitializing a held lock:
87 debug_check_no_locks_freed((void *)lock, sizeof(*lock));
88 lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_SLEEP);
94 * mutex_destroy - mark a mutex unusable
95 * @lock: the mutex to be destroyed
97 * This function marks the mutex uninitialized, and any subsequent
98 * use of the mutex is forbidden. The mutex must not be locked when
99 * this function is called.
101 void mutex_destroy(struct mutex *lock)
103 DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
107 EXPORT_SYMBOL_GPL(mutex_destroy);