kernel/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/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);