lockdep: fix debug_lock_alloc

[deliverable/linux.git] / kernel / lockdep.c

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index d3c72ad8d09ee23e93269588fa7c443c548679f6..1aa91fd6b06ec341897646f2322e35920640f448 100644 (file)
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -1372,18 +1372,32 @@ check_deadlock(struct task_struct *curr, struct held_lock *next,
               struct lockdep_map *next_instance, int read)
 {
        struct held_lock *prev;
+       struct held_lock *nest = NULL;
        int i;
 
        for (i = 0; i < curr->lockdep_depth; i++) {
                prev = curr->held_locks + i;
+
+               if (prev->instance == next->nest_lock)
+                       nest = prev;
+
                if (hlock_class(prev) != hlock_class(next))
                        continue;
+
                /*
                 * Allow read-after-read recursion of the same
                 * lock class (i.e. read_lock(lock)+read_lock(lock)):
                 */
                if ((read == 2) && prev->read)
                        return 2;
+
+               /*
+                * We're holding the nest_lock, which serializes this lock's
+                * nesting behaviour.
+                */
+               if (nest)
+                       return 2;
+
                return print_deadlock_bug(curr, prev, next);
        }
        return 1;
@@ -2507,7 +2521,7 @@ EXPORT_SYMBOL_GPL(lockdep_init_map);
  */
 static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
                          int trylock, int read, int check, int hardirqs_off,
-                         unsigned long ip)
+                         struct lockdep_map *nest_lock, unsigned long ip)
 {
        struct task_struct *curr = current;
        struct lock_class *class = NULL;
@@ -2566,6 +2580,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
        hlock->class_idx = class - lock_classes + 1;
        hlock->acquire_ip = ip;
        hlock->instance = lock;
+       hlock->nest_lock = nest_lock;
        hlock->trylock = trylock;
        hlock->read = read;
        hlock->check = check;
@@ -2717,7 +2732,7 @@ found_it:
                if (!__lock_acquire(hlock->instance,
                        hlock_class(hlock)->subclass, hlock->trylock,
                                hlock->read, hlock->check, hlock->hardirqs_off,
-                               hlock->acquire_ip))
+                               hlock->nest_lock, hlock->acquire_ip))
                        return 0;
        }
 
@@ -2778,7 +2793,7 @@ found_it:
                if (!__lock_acquire(hlock->instance,
                        hlock_class(hlock)->subclass, hlock->trylock,
                                hlock->read, hlock->check, hlock->hardirqs_off,
-                               hlock->acquire_ip))
+                               hlock->nest_lock, hlock->acquire_ip))
                        return 0;
        }
 
@@ -2915,13 +2930,11 @@ EXPORT_SYMBOL_GPL(lock_set_subclass);
  * and also avoid lockdep recursion:
  */
 void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
-                         int trylock, int read, int check, unsigned long ip)
+                         int trylock, int read, int check,
+                         struct lockdep_map *nest_lock, unsigned long ip)
 {
        unsigned long flags;
 
-       if (unlikely(!lock_stat && !prove_locking))
-               return;
-
        if (unlikely(current->lockdep_recursion))
                return;
 
@@ -2930,7 +2943,7 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 
        current->lockdep_recursion = 1;
        __lock_acquire(lock, subclass, trylock, read, check,
-                      irqs_disabled_flags(flags), ip);
+                      irqs_disabled_flags(flags), nest_lock, ip);
        current->lockdep_recursion = 0;
        raw_local_irq_restore(flags);
 }
@@ -2942,9 +2955,6 @@ void lock_release(struct lockdep_map *lock, int nested,
 {
        unsigned long flags;
 
-       if (unlikely(!lock_stat && !prove_locking))
-               return;
-
        if (unlikely(current->lockdep_recursion))
                return;
 
@@ -3160,6 +3170,7 @@ static void zap_class(struct lock_class *class)
        list_del_rcu(&class->hash_entry);
        list_del_rcu(&class->lock_entry);
 
+       class->key = NULL;
 }
 
 static inline int within(const void *addr, void *start, unsigned long size)