1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun * kernel/mutex-debug.c
3*4882a593Smuzhiyun *
4*4882a593Smuzhiyun * Debugging code for mutexes
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun * Started by Ingo Molnar:
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
9*4882a593Smuzhiyun *
10*4882a593Smuzhiyun * lock debugging, locking tree, deadlock detection started by:
11*4882a593Smuzhiyun *
12*4882a593Smuzhiyun * Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
13*4882a593Smuzhiyun * Released under the General Public License (GPL).
14*4882a593Smuzhiyun */
15*4882a593Smuzhiyun #include <linux/mutex.h>
16*4882a593Smuzhiyun #include <linux/delay.h>
17*4882a593Smuzhiyun #include <linux/export.h>
18*4882a593Smuzhiyun #include <linux/poison.h>
19*4882a593Smuzhiyun #include <linux/sched.h>
20*4882a593Smuzhiyun #include <linux/spinlock.h>
21*4882a593Smuzhiyun #include <linux/kallsyms.h>
22*4882a593Smuzhiyun #include <linux/interrupt.h>
23*4882a593Smuzhiyun #include <linux/debug_locks.h>
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun #include "mutex-debug.h"
26*4882a593Smuzhiyun
27*4882a593Smuzhiyun /*
28*4882a593Smuzhiyun * Must be called with lock->wait_lock held.
29*4882a593Smuzhiyun */
debug_mutex_lock_common(struct mutex * lock,struct mutex_waiter * waiter)30*4882a593Smuzhiyun void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
33*4882a593Smuzhiyun waiter->magic = waiter;
34*4882a593Smuzhiyun INIT_LIST_HEAD(&waiter->list);
35*4882a593Smuzhiyun }
36*4882a593Smuzhiyun
debug_mutex_wake_waiter(struct mutex * lock,struct mutex_waiter * waiter)37*4882a593Smuzhiyun void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
38*4882a593Smuzhiyun {
39*4882a593Smuzhiyun lockdep_assert_held(&lock->wait_lock);
40*4882a593Smuzhiyun DEBUG_LOCKS_WARN_ON(list_empty(&lock->wait_list));
41*4882a593Smuzhiyun DEBUG_LOCKS_WARN_ON(waiter->magic != waiter);
42*4882a593Smuzhiyun DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
43*4882a593Smuzhiyun }
44*4882a593Smuzhiyun
debug_mutex_free_waiter(struct mutex_waiter * waiter)45*4882a593Smuzhiyun void debug_mutex_free_waiter(struct mutex_waiter *waiter)
46*4882a593Smuzhiyun {
47*4882a593Smuzhiyun DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
48*4882a593Smuzhiyun memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
49*4882a593Smuzhiyun }
50*4882a593Smuzhiyun
debug_mutex_add_waiter(struct mutex * lock,struct mutex_waiter * waiter,struct task_struct * task)51*4882a593Smuzhiyun void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
52*4882a593Smuzhiyun struct task_struct *task)
53*4882a593Smuzhiyun {
54*4882a593Smuzhiyun lockdep_assert_held(&lock->wait_lock);
55*4882a593Smuzhiyun
56*4882a593Smuzhiyun /* Mark the current thread as blocked on the lock: */
57*4882a593Smuzhiyun task->blocked_on = waiter;
58*4882a593Smuzhiyun }
59*4882a593Smuzhiyun
debug_mutex_remove_waiter(struct mutex * lock,struct mutex_waiter * waiter,struct task_struct * task)60*4882a593Smuzhiyun void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
61*4882a593Smuzhiyun struct task_struct *task)
62*4882a593Smuzhiyun {
63*4882a593Smuzhiyun DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
64*4882a593Smuzhiyun DEBUG_LOCKS_WARN_ON(waiter->task != task);
65*4882a593Smuzhiyun DEBUG_LOCKS_WARN_ON(task->blocked_on != waiter);
66*4882a593Smuzhiyun task->blocked_on = NULL;
67*4882a593Smuzhiyun
68*4882a593Smuzhiyun INIT_LIST_HEAD(&waiter->list);
69*4882a593Smuzhiyun waiter->task = NULL;
70*4882a593Smuzhiyun }
71*4882a593Smuzhiyun
debug_mutex_unlock(struct mutex * lock)72*4882a593Smuzhiyun void debug_mutex_unlock(struct mutex *lock)
73*4882a593Smuzhiyun {
74*4882a593Smuzhiyun if (likely(debug_locks)) {
75*4882a593Smuzhiyun DEBUG_LOCKS_WARN_ON(lock->magic != lock);
76*4882a593Smuzhiyun DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
77*4882a593Smuzhiyun }
78*4882a593Smuzhiyun }
79*4882a593Smuzhiyun
debug_mutex_init(struct mutex * lock,const char * name,struct lock_class_key * key)80*4882a593Smuzhiyun void debug_mutex_init(struct mutex *lock, const char *name,
81*4882a593Smuzhiyun struct lock_class_key *key)
82*4882a593Smuzhiyun {
83*4882a593Smuzhiyun #ifdef CONFIG_DEBUG_LOCK_ALLOC
84*4882a593Smuzhiyun /*
85*4882a593Smuzhiyun * Make sure we are not reinitializing a held lock:
86*4882a593Smuzhiyun */
87*4882a593Smuzhiyun debug_check_no_locks_freed((void *)lock, sizeof(*lock));
88*4882a593Smuzhiyun lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_SLEEP);
89*4882a593Smuzhiyun #endif
90*4882a593Smuzhiyun lock->magic = lock;
91*4882a593Smuzhiyun }
92*4882a593Smuzhiyun
93*4882a593Smuzhiyun /***
94*4882a593Smuzhiyun * mutex_destroy - mark a mutex unusable
95*4882a593Smuzhiyun * @lock: the mutex to be destroyed
96*4882a593Smuzhiyun *
97*4882a593Smuzhiyun * This function marks the mutex uninitialized, and any subsequent
98*4882a593Smuzhiyun * use of the mutex is forbidden. The mutex must not be locked when
99*4882a593Smuzhiyun * this function is called.
100*4882a593Smuzhiyun */
mutex_destroy(struct mutex * lock)101*4882a593Smuzhiyun void mutex_destroy(struct mutex *lock)
102*4882a593Smuzhiyun {
103*4882a593Smuzhiyun DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
104*4882a593Smuzhiyun lock->magic = NULL;
105*4882a593Smuzhiyun }
106*4882a593Smuzhiyun
107*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(mutex_destroy);
108