From: Sven Eckelmann sven@narfation.org
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 Signed-off-by: Antonio Quartulli ordex@autistici.org --- net/batman-adv/bridge_loop_avoidance.c | 13 +++++++++++++ net/batman-adv/hash.c | 9 +++++++++ net/batman-adv/hash.h | 4 ++++ 3 files changed, 26 insertions(+)
diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c index 8bf9751..5c1ac55 100644 --- a/net/batman-adv/bridge_loop_avoidance.c +++ b/net/batman-adv/bridge_loop_avoidance.c @@ -1127,6 +1127,14 @@ out: 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) { @@ -1164,6 +1172,11 @@ int bla_init(struct bat_priv *bat_priv) 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");
bla_start_timer(bat_priv); diff --git a/net/batman-adv/hash.c b/net/batman-adv/hash.c index 117687b..5b2eabe 100644 --- a/net/batman-adv/hash.c +++ b/net/batman-adv/hash.c @@ -69,3 +69,12 @@ free_hash: 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); +} diff --git a/net/batman-adv/hash.h b/net/batman-adv/hash.h index d4bd786..93b3c71 100644 --- a/net/batman-adv/hash.h +++ b/net/batman-adv/hash.h @@ -45,6 +45,10 @@ struct hashtable_t { /* 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);