mutex-debug.c

  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>
 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>
 23 
 24 #include "mutex-debug.h"
 25 
 26 /*
 27  * Must be called with lock->wait_lock held.
 28  */
 29 void debug_mutex_set_owner(struct mutex *lock, struct thread_info *new_owner)
 30 {
 31         lock->owner = new_owner;
 32 }
 33 
 34 void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
 35 {
 36         memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
 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 {
 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));
 47 }
 48 
 49 void debug_mutex_free_waiter(struct mutex_waiter *waiter)
 50 {
 51         DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
 52         memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
 53 }
 54 
 55 void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
 56                             struct thread_info *ti)
 57 {
 58         SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
 59 
 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 {
 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);
 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 {
 79         if (unlikely(!debug_locks))
 80                 return;
 81 
 82         DEBUG_LOCKS_WARN_ON(lock->magic != lock);
 83         DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
 84         DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
 85         DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
 86 }
 87 
 88 void debug_mutex_init(struct mutex *lock, const char *name,
 89                       struct lock_class_key *key)
 90 {
 91 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 92         /*
 93          * Make sure we are not reinitializing a held lock:
 94          */
 95         debug_check_no_locks_freed((void *)lock, sizeof(*lock));
 96         lockdep_init_map(&lock->dep_map, name, key, 0);
 97 #endif
 98         lock->owner = NULL;
 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  */
110 void mutex_destroy(struct mutex *lock)
111 {
112         DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
113         lock->magic = NULL;
114 }
115 
116 EXPORT_SYMBOL_GPL(mutex_destroy);
117
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Linux/kernel/mutex-debug.c
