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 --- bridge_loop_avoidance.c | 11 +++++++++++ hash.c | 9 +++++++++ hash.h | 3 +++ 3 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/bridge_loop_avoidance.c b/bridge_loop_avoidance.c index 8a17a78..c74d8a2 100644 --- a/bridge_loop_avoidance.c +++ b/bridge_loop_avoidance.c @@ -1124,6 +1124,14 @@ 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) { @@ -1158,6 +1166,9 @@ int bla_init(struct bat_priv *bat_priv) bat_priv->claim_hash = hash_new(128); bat_priv->backbone_hash = hash_new(32);
+ hash_set_lock_class(bat_priv->claim_hash, &claim_hash_lock_class_key); + hash_set_lock_class(bat_priv->backbone_hash, &backbone_hash_lock_class_key); + if (!bat_priv->claim_hash || !bat_priv->backbone_hash) return -1;
diff --git a/hash.c b/hash.c index 117687b..13d4597 100644 --- a/hash.c +++ b/hash.c @@ -69,3 +69,12 @@ free_hash: kfree(hash); return NULL; } + +void 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/hash.h b/hash.h index d4bd786..7bcb98f 100644 --- a/hash.h +++ b/hash.h @@ -45,6 +45,9 @@ struct hashtable_t { /* allocates and clears the hash */ struct hashtable_t *hash_new(uint32_t size);
+/* set class key for all locks */ +void 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);