batman-adv: Initialize lockdep class keys for hashes

The hash for claim and backbone hash in the bridge loop avoidance code receive the same key because they are getting initialized by hash_new with the same key. Lockdep will create a backtrace when they are used recursively. This can be avoided by reinitializing the key directly after the hash_new. Signed-off-by: Sven Eckelmann <sven@narfation.org>

batman-adv: Initialize lockdep class keys for hashes
The hash for claim and backbone hash in the bridge loop avoidance code receive the same key because they are getting initialized by hash_new with the same key. Lockdep will create a backtrace when they are used recursively. This can be avoided by reinitializing the key directly after the hash_new. Signed-off-by: Sven Eckelmann <sven@narfation.org>
Sven Eckelmann · Antonio Quartulli
1 parent d2b6cc8e46
Showing 3 changed files with 26 additions and 0 deletions Side-by-side Diff
net/batman-adv/bridge_loop_avoidance.c
net/batman-adv/hash.c
net/batman-adv/hash.h
@@ -1127,6 +1127,14 @@
 	bla_start_timer(bat_priv);
 }
  
+/* The hash for claim and backbone hash receive the same key because they
+ * are getting initialized by hash_new with the same key. Reinitializing
+ * them with to different keys to allow nested locking without generating
+ * lockdep warnings
+ */
+static struct lock_class_key claim_hash_lock_class_key;
+static struct lock_class_key backbone_hash_lock_class_key;
+
 /* initialize all bla structures */
 int bla_init(struct bat_priv *bat_priv)
 {
@@ -1163,6 +1171,11 @@
  
 	if (!bat_priv->claim_hash || !bat_priv->backbone_hash)
 		return -1;
+
+	batadv_hash_set_lock_class(bat_priv->claim_hash,
+				   &claim_hash_lock_class_key);
+	batadv_hash_set_lock_class(bat_priv->backbone_hash,
+				   &backbone_hash_lock_class_key);
  
 	bat_dbg(DBG_BLA, bat_priv, "bla hashes initialized\n");
  
@@ -69,4 +69,13 @@
 	kfree(hash);
 	return NULL;
 }
+
+void batadv_hash_set_lock_class(struct hashtable_t *hash,
+				struct lock_class_key *key)
+{
+	uint32_t i;
+
+	for (i = 0; i < hash->size; i++)
+		lockdep_set_class(&hash->list_locks[i], key);
+}
@@ -45,6 +45,10 @@
 /* allocates and clears the hash */
 struct hashtable_t *hash_new(uint32_t size);
  
+/* set class key for all locks */
+void batadv_hash_set_lock_class(struct hashtable_t *hash,
+				struct lock_class_key *key);
+
 /* free only the hashtable and the hash itself. */
 void hash_destroy(struct hashtable_t *hash);
...	...	@@ -1127,6 +1127,14 @@
1127	1127	bla_start_timer(bat_priv);
1128	1128	}
1129	1129
	1130	+/* The hash for claim and backbone hash receive the same key because they
	1131	+ * are getting initialized by hash_new with the same key. Reinitializing
	1132	+ * them with to different keys to allow nested locking without generating
	1133	+ * lockdep warnings
	1134	+ */
	1135	+static struct lock_class_key claim_hash_lock_class_key;
	1136	+static struct lock_class_key backbone_hash_lock_class_key;
	1137	+
1130	1138	/* initialize all bla structures */
1131	1139	int bla_init(struct bat_priv *bat_priv)
1132	1140	{
...	...	@@ -1163,6 +1171,11 @@
1163	1171
1164	1172	if (!bat_priv->claim_hash \|\| !bat_priv->backbone_hash)
1165	1173	return -1;
	1174	+
	1175	+ batadv_hash_set_lock_class(bat_priv->claim_hash,
	1176	+ &claim_hash_lock_class_key);
	1177	+ batadv_hash_set_lock_class(bat_priv->backbone_hash,
	1178	+ &backbone_hash_lock_class_key);
1166	1179
1167	1180	bat_dbg(DBG_BLA, bat_priv, "bla hashes initialized\n");
1168	1181
...	...	@@ -69,4 +69,13 @@
69	69	kfree(hash);
70	70	return NULL;
71	71	}
	72	+
	73	+void batadv_hash_set_lock_class(struct hashtable_t *hash,
	74	+ struct lock_class_key *key)
	75	+{
	76	+ uint32_t i;
	77	+
	78	+ for (i = 0; i < hash->size; i++)
	79	+ lockdep_set_class(&hash->list_locks[i], key);
	80	+}
...	...	@@ -45,6 +45,10 @@
45	45	/* allocates and clears the hash */
46	46	struct hashtable_t *hash_new(uint32_t size);
47	47
	48	+/* set class key for all locks */
	49	+void batadv_hash_set_lock_class(struct hashtable_t *hash,
	50	+ struct lock_class_key *key);
	51	+
48	52	/* free only the hashtable and the hash itself. */
49	53	void hash_destroy(struct hashtable_t *hash);
50	54