2 * Debugging code for mutexes
4 * Started by Ingo Molnar:
6 * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
8 * lock debugging, locking tree, deadlock detection started by:
10 * Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
11 * Released under the General Public License (GPL).
13 #include <linux/mutex.h>
14 #include <linux/delay.h>
15 #include <linux/export.h>
16 #include <linux/poison.h>
17 #include <linux/sched.h>
18 #include <linux/spinlock.h>
19 #include <linux/kallsyms.h>
20 #include <linux/interrupt.h>
21 #include <linux/debug_locks.h>
26 * Must be called with lock->wait_lock held.
28 void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
30 memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
31 waiter->magic = waiter;
32 INIT_LIST_HEAD(&waiter->list);
35 void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
37 lockdep_assert_held(&lock->wait_lock);
38 DEBUG_LOCKS_WARN_ON(list_empty(&lock->wait_list));
39 DEBUG_LOCKS_WARN_ON(waiter->magic != waiter);
40 DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
43 void debug_mutex_free_waiter(struct mutex_waiter *waiter)
45 DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
46 memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
49 void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
50 struct task_struct *task)
52 lockdep_assert_held(&lock->wait_lock);
54 /* Mark the current thread as blocked on the lock: */
55 task->blocked_on = waiter;
58 void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
59 struct task_struct *task)
61 DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
62 DEBUG_LOCKS_WARN_ON(waiter->task != task);
63 DEBUG_LOCKS_WARN_ON(task->blocked_on != waiter);
64 task->blocked_on = NULL;
66 INIT_LIST_HEAD(&waiter->list);
70 void debug_mutex_unlock(struct mutex *lock)
72 if (likely(debug_locks)) {
73 DEBUG_LOCKS_WARN_ON(lock->magic != lock);
74 DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
78 void debug_mutex_init(struct mutex *lock, const char *name,
79 struct lock_class_key *key)
81 #ifdef CONFIG_DEBUG_LOCK_ALLOC
83 * Make sure we are not reinitializing a held lock:
85 debug_check_no_locks_freed((void *)lock, sizeof(*lock));
86 lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_SLEEP);
92 * mutex_destroy - mark a mutex unusable
93 * @lock: the mutex to be destroyed
95 * This function marks the mutex uninitialized, and any subsequent
96 * use of the mutex is forbidden. The mutex must not be locked when
97 * this function is called.
99 void mutex_destroy(struct mutex *lock)
101 DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
105 EXPORT_SYMBOL_GPL(mutex_destroy);