1 files changed, 27 insertions, 2 deletions

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 28fbeb2a10cc..d1a6daf1f51f 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -736,6 +736,25 @@ static bool assign_lock_key(struct lockdep_map *lock)
 }
 
 /*
+ * Initialize the lock_classes[] array elements.
+ */
+static void init_data_structures_once(void)
+{
+	static bool initialization_happened;
+	int i;
+
+	if (likely(initialization_happened))
+		return;
+
+	initialization_happened = true;
+
+	for (i = 0; i < ARRAY_SIZE(lock_classes); i++) {
+		INIT_LIST_HEAD(&lock_classes[i].locks_after);
+		INIT_LIST_HEAD(&lock_classes[i].locks_before);
+	}
+}
+
+/*
  * Register a lock's class in the hash-table, if the class is not present
  * yet. Otherwise we look it up. We cache the result in the lock object
  * itself, so actual lookup of the hash should be once per lock object.
@@ -775,6 +794,8 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
 			goto out_unlock_set;
 	}
 
+	init_data_structures_once();
+
 	/*
 	 * Allocate a new key from the static array, and add it to
 	 * the hash:
@@ -793,8 +814,8 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
 	class->key = key;
 	class->name = lock->name;
 	class->subclass = subclass;
-	INIT_LIST_HEAD(&class->locks_before);
-	INIT_LIST_HEAD(&class->locks_after);
+	WARN_ON_ONCE(!list_empty(&class->locks_before));
+	WARN_ON_ONCE(!list_empty(&class->locks_after));
 	class->name_version = count_matching_names(class);
 	/*
 	 * We use RCU's safe list-add method to make
@@ -4155,6 +4176,8 @@ void lockdep_free_key_range(void *start, unsigned long size)
 	int i;
 	int locked;
 
+	init_data_structures_once();
+
 	raw_local_irq_save(flags);
 	locked = graph_lock();
 
@@ -4218,6 +4241,8 @@ void lockdep_reset_lock(struct lockdep_map *lock)
 	unsigned long flags;
 	int j, locked;
 
+	init_data_structures_once();
+
 	raw_local_irq_save(flags);
 	locked = graph_lock();