Commit eb9ed3ee authored by Sven Eckelmann's avatar Sven Eckelmann Committed by Luis Henriques

batman-adv: Drop immediate orig_node free function

commit 42eff6a6 upstream.

It is not allowed to free the memory of an object which is part of a list
which is protected by rcu-read-side-critical sections without making sure
that no other context is accessing the object anymore. This usually happens
by removing the references to this object and then waiting until the rcu
grace period is over and no one (allowedly) accesses it anymore.

But the _now functions ignore this completely. They free the object
directly even when a different context still tries to access it. This has
to be avoided and thus these functions must be removed and all functions
have to use batadv_orig_node_free_ref.

Fixes: 72822225 ("batman-adv: Fix rcu_barrier() miss due to double call_rcu() in TT code")
Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
Signed-off-by: default avatarMarek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: default avatarAntonio Quartulli <a@unstable.cc>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent 7ec2a7c6
...@@ -563,17 +563,6 @@ void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node) ...@@ -563,17 +563,6 @@ void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node)
batadv_orig_node_release(orig_node); batadv_orig_node_release(orig_node);
} }
/**
* batadv_orig_node_free_ref_now - decrement the orig node refcounter and
* possibly free it (without rcu callback)
* @orig_node: the orig node to free
*/
void batadv_orig_node_free_ref_now(struct batadv_orig_node *orig_node)
{
if (atomic_dec_and_test(&orig_node->refcount))
batadv_orig_node_free_rcu(&orig_node->rcu);
}
void batadv_originator_free(struct batadv_priv *bat_priv) void batadv_originator_free(struct batadv_priv *bat_priv)
{ {
struct batadv_hashtable *hash = bat_priv->orig_hash; struct batadv_hashtable *hash = bat_priv->orig_hash;
......
...@@ -25,7 +25,6 @@ int batadv_originator_init(struct batadv_priv *bat_priv); ...@@ -25,7 +25,6 @@ int batadv_originator_init(struct batadv_priv *bat_priv);
void batadv_originator_free(struct batadv_priv *bat_priv); void batadv_originator_free(struct batadv_priv *bat_priv);
void batadv_purge_orig_ref(struct batadv_priv *bat_priv); void batadv_purge_orig_ref(struct batadv_priv *bat_priv);
void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node); void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node);
void batadv_orig_node_free_ref_now(struct batadv_orig_node *orig_node);
struct batadv_orig_node *batadv_orig_node_new(struct batadv_priv *bat_priv, struct batadv_orig_node *batadv_orig_node_new(struct batadv_priv *bat_priv,
const uint8_t *addr); const uint8_t *addr);
struct batadv_neigh_node * struct batadv_neigh_node *
......
...@@ -219,20 +219,6 @@ int batadv_tt_global_hash_count(struct batadv_priv *bat_priv, ...@@ -219,20 +219,6 @@ int batadv_tt_global_hash_count(struct batadv_priv *bat_priv,
return count; return count;
} }
static void batadv_tt_orig_list_entry_free_rcu(struct rcu_head *rcu)
{
struct batadv_tt_orig_list_entry *orig_entry;
orig_entry = container_of(rcu, struct batadv_tt_orig_list_entry, rcu);
/* We are in an rcu callback here, therefore we cannot use
* batadv_orig_node_free_ref() and its call_rcu():
* An rcu_barrier() wouldn't wait for that to finish
*/
batadv_orig_node_free_ref_now(orig_entry->orig_node);
kfree(orig_entry);
}
/** /**
* batadv_tt_local_size_mod - change the size by v of the local table identified * batadv_tt_local_size_mod - change the size by v of the local table identified
* by vid * by vid
...@@ -328,13 +314,25 @@ static void batadv_tt_global_size_dec(struct batadv_orig_node *orig_node, ...@@ -328,13 +314,25 @@ static void batadv_tt_global_size_dec(struct batadv_orig_node *orig_node,
batadv_tt_global_size_mod(orig_node, vid, -1); batadv_tt_global_size_mod(orig_node, vid, -1);
} }
/**
* batadv_tt_orig_list_entry_release - release tt orig entry from lists and
* queue for free after rcu grace period
* @orig_entry: tt orig entry to be free'd
*/
static void
batadv_tt_orig_list_entry_release(struct batadv_tt_orig_list_entry *orig_entry)
{
batadv_orig_node_free_ref(orig_entry->orig_node);
kfree_rcu(orig_entry, rcu);
}
static void static void
batadv_tt_orig_list_entry_free_ref(struct batadv_tt_orig_list_entry *orig_entry) batadv_tt_orig_list_entry_free_ref(struct batadv_tt_orig_list_entry *orig_entry)
{ {
if (!atomic_dec_and_test(&orig_entry->refcount)) if (!atomic_dec_and_test(&orig_entry->refcount))
return; return;
call_rcu(&orig_entry->rcu, batadv_tt_orig_list_entry_free_rcu); batadv_tt_orig_list_entry_release(orig_entry);
} }
/** /**
......
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