| 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/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> |
| 24 | |
| 25 | #include "mutex-debug.h" |
| 26 | |
| 27 | /* |
| 28 | * Must be called with lock->wait_lock held. |
| 29 | */ |
| 30 | void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter) |
| 31 | { |
| 32 | memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter)); |
| 33 | waiter->magic = waiter; |
| 34 | INIT_LIST_HEAD(&waiter->list); |
| 35 | } |
| 36 | |
| 37 | void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter) |
| 38 | { |
| 39 | SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock)); |
| 40 | if(DEBUG_LOCKS_WARN_ON(list_empty(&lock->wait_list))){ |
| 41 | printk("[MUTEX WARN!!]\n"); |
| 42 | } |
| 43 | if(DEBUG_LOCKS_WARN_ON(waiter->magic != waiter)){ |
| 44 | printk("[MUTEX WARN!!] bad magic number %p:%p\n", waiter->magic, waiter); |
| 45 | } |
| 46 | if(DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list))){ |
| 47 | printk("[MUTEX WARN!!] empt waiter list\n"); |
| 48 | } |
| 49 | } |
| 50 | |
| 51 | void debug_mutex_free_waiter(struct mutex_waiter *waiter) |
| 52 | { |
| 53 | DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list)); |
| 54 | memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter)); |
| 55 | } |
| 56 | |
| 57 | void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter, |
| 58 | struct thread_info *ti) |
| 59 | { |
| 60 | SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock)); |
| 61 | |
| 62 | /* Mark the current thread as blocked on the lock: */ |
| 63 | ti->task->blocked_on = waiter; |
| 64 | #ifdef CONFIG_MT_DEBUG_MUTEXES |
| 65 | waiter->task_wait_on = lock->owner; |
| 66 | #endif |
| 67 | } |
| 68 | |
| 69 | void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter, |
| 70 | struct thread_info *ti) |
| 71 | { |
| 72 | if(DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list))){ |
| 73 | printk("[MUTEX WARN!!] empty waiter list\n"); |
| 74 | } |
| 75 | if(DEBUG_LOCKS_WARN_ON(waiter->task != ti->task)){ |
| 76 | printk("[MUTEX WARN!!] waiter task is not the same![%d:%s] != [%d:%s]\n", waiter->task->pid, waiter->task->comm, ti->task->pid, ti->task->comm); |
| 77 | } |
| 78 | if(DEBUG_LOCKS_WARN_ON(ti->task->blocked_on != waiter)){ |
| 79 | printk("[MUTEX WARN!!] blocked on different waiter\n"); |
| 80 | } |
| 81 | ti->task->blocked_on = NULL; |
| 82 | |
| 83 | list_del_init(&waiter->list); |
| 84 | waiter->task = NULL; |
| 85 | #ifdef CONFIG_MT_DEBUG_MUTEXES |
| 86 | waiter->task_wait_on = NULL; |
| 87 | #endif |
| 88 | } |
| 89 | |
| 90 | void debug_mutex_unlock(struct mutex *lock) |
| 91 | { |
| 92 | // if (unlikely(!debug_locks)) |
| 93 | // return; |
| 94 | |
| 95 | if(DEBUG_LOCKS_WARN_ON(lock->magic != lock)){ |
| 96 | printk("[MUTEX WARN!!] bad lock magic:%p\n", lock->magic); |
| 97 | } |
| 98 | if(DEBUG_LOCKS_WARN_ON(lock->owner != current)){ |
| 99 | if(lock->owner != NULL){ |
| 100 | printk("[MUTEX WARN!!] releasing mutex which is hold by another process, %p\n", lock->owner); |
| 101 | printk("[MUTEX WARN!!] current process[%d:%s] is trying to release lock\n But it should be released by lock owner-process[%d:%s]\n", current->pid, current->comm, lock->owner->pid, lock->owner->comm); |
| 102 | }else |
| 103 | printk("\n[MUTEX WARN!!] imbalanced unlock\n"); |
| 104 | } |
| 105 | if(DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next)){ |
| 106 | printk("[MUTEX WARN!!] wait_list both empty in prev and next \n"); |
| 107 | } |
| 108 | mutex_clear_owner(lock); |
| 109 | } |
| 110 | |
| 111 | void debug_mutex_init(struct mutex *lock, const char *name, |
| 112 | struct lock_class_key *key) |
| 113 | { |
| 114 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| 115 | /* |
| 116 | * Make sure we are not reinitializing a held lock: |
| 117 | */ |
| 118 | debug_check_no_locks_freed((void *)lock, sizeof(*lock)); |
| 119 | lockdep_init_map(&lock->dep_map, name, key, 0); |
| 120 | #endif |
| 121 | #ifdef CONFIG_DEBUG_MUTEXES |
| 122 | lock->name = name; |
| 123 | #endif |
| 124 | lock->magic = lock; |
| 125 | } |
| 126 | |
| 127 | /*** |
| 128 | * mutex_destroy - mark a mutex unusable |
| 129 | * @lock: the mutex to be destroyed |
| 130 | * |
| 131 | * This function marks the mutex uninitialized, and any subsequent |
| 132 | * use of the mutex is forbidden. The mutex must not be locked when |
| 133 | * this function is called. |
| 134 | */ |
| 135 | void mutex_destroy(struct mutex *lock) |
| 136 | { |
| 137 | DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock)); |
| 138 | lock->magic = NULL; |
| 139 | } |
| 140 | |
| 141 | EXPORT_SYMBOL_GPL(mutex_destroy); |