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/module.h>
18 #include <linux/poison.h>
19 #include <linux/spinlock.h>
20 #include <linux/kallsyms.h>
21 #include <linux/interrupt.h>
22 #include <linux/debug_locks.h>
24 #include "mutex-debug.h"
27 * Must be called with lock->wait_lock held.
29 void debug_mutex_lock_common(struct mutex
*lock
, struct mutex_waiter
*waiter
)
31 memset(waiter
, MUTEX_DEBUG_INIT
, sizeof(*waiter
));
32 waiter
->magic
= waiter
;
33 INIT_LIST_HEAD(&waiter
->list
);
36 void debug_mutex_wake_waiter(struct mutex
*lock
, struct mutex_waiter
*waiter
)
38 SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock
->wait_lock
));
39 DEBUG_LOCKS_WARN_ON(list_empty(&lock
->wait_list
));
40 DEBUG_LOCKS_WARN_ON(waiter
->magic
!= waiter
);
41 DEBUG_LOCKS_WARN_ON(list_empty(&waiter
->list
));
44 void debug_mutex_free_waiter(struct mutex_waiter
*waiter
)
46 DEBUG_LOCKS_WARN_ON(!list_empty(&waiter
->list
));
47 memset(waiter
, MUTEX_DEBUG_FREE
, sizeof(*waiter
));
50 void debug_mutex_add_waiter(struct mutex
*lock
, struct mutex_waiter
*waiter
,
51 struct thread_info
*ti
)
53 SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock
->wait_lock
));
55 /* Mark the current thread as blocked on the lock: */
56 ti
->task
->blocked_on
= waiter
;
59 void mutex_remove_waiter(struct mutex
*lock
, struct mutex_waiter
*waiter
,
60 struct thread_info
*ti
)
62 DEBUG_LOCKS_WARN_ON(list_empty(&waiter
->list
));
63 DEBUG_LOCKS_WARN_ON(waiter
->task
!= ti
->task
);
64 DEBUG_LOCKS_WARN_ON(ti
->task
->blocked_on
!= waiter
);
65 ti
->task
->blocked_on
= NULL
;
67 list_del_init(&waiter
->list
);
71 void debug_mutex_unlock(struct mutex
*lock
)
73 if (unlikely(!debug_locks
))
76 DEBUG_LOCKS_WARN_ON(lock
->magic
!= lock
);
77 DEBUG_LOCKS_WARN_ON(lock
->owner
!= current_thread_info());
78 DEBUG_LOCKS_WARN_ON(!lock
->wait_list
.prev
&& !lock
->wait_list
.next
);
79 mutex_clear_owner(lock
);
82 void debug_mutex_init(struct mutex
*lock
, const char *name
,
83 struct lock_class_key
*key
)
85 #ifdef CONFIG_DEBUG_LOCK_ALLOC
87 * Make sure we are not reinitializing a held lock:
89 debug_check_no_locks_freed((void *)lock
, sizeof(*lock
));
90 lockdep_init_map(&lock
->dep_map
, name
, key
, 0);
96 * mutex_destroy - mark a mutex unusable
97 * @lock: the mutex to be destroyed
99 * This function marks the mutex uninitialized, and any subsequent
100 * use of the mutex is forbidden. The mutex must not be locked when
101 * this function is called.
103 void mutex_destroy(struct mutex
*lock
)
105 DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock
));
109 EXPORT_SYMBOL_GPL(mutex_destroy
);
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