Commit a03f20f4 authored by Sven Eckelmann's avatar Sven Eckelmann Committed by Luis Henriques

batman-adv: Drop immediate neigh_ifinfo free function

commit ae3e1e36 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_neigh_ifinfo_free_ref.

Fixes: 89652331 ("batman-adv: split tq information in neigh_node struct")
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 dd876ecc
...@@ -150,42 +150,28 @@ int batadv_originator_init(struct batadv_priv *bat_priv) ...@@ -150,42 +150,28 @@ int batadv_originator_init(struct batadv_priv *bat_priv)
} }
/** /**
* batadv_neigh_ifinfo_free_rcu - free the neigh_ifinfo object * batadv_neigh_ifinfo_release - release neigh_ifinfo from lists and queue for
* @rcu: rcu pointer of the neigh_ifinfo object * free after rcu grace period
*/
static void batadv_neigh_ifinfo_free_rcu(struct rcu_head *rcu)
{
struct batadv_neigh_ifinfo *neigh_ifinfo;
neigh_ifinfo = container_of(rcu, struct batadv_neigh_ifinfo, rcu);
if (neigh_ifinfo->if_outgoing != BATADV_IF_DEFAULT)
batadv_hardif_free_ref_now(neigh_ifinfo->if_outgoing);
kfree(neigh_ifinfo);
}
/**
* batadv_neigh_ifinfo_free_now - decrement the refcounter and possibly free
* the neigh_ifinfo (without rcu callback)
* @neigh_ifinfo: the neigh_ifinfo object to release * @neigh_ifinfo: the neigh_ifinfo object to release
*/ */
static void static void
batadv_neigh_ifinfo_free_ref_now(struct batadv_neigh_ifinfo *neigh_ifinfo) batadv_neigh_ifinfo_release(struct batadv_neigh_ifinfo *neigh_ifinfo)
{ {
if (atomic_dec_and_test(&neigh_ifinfo->refcount)) if (neigh_ifinfo->if_outgoing != BATADV_IF_DEFAULT)
batadv_neigh_ifinfo_free_rcu(&neigh_ifinfo->rcu); batadv_hardif_free_ref(neigh_ifinfo->if_outgoing);
kfree_rcu(neigh_ifinfo, rcu);
} }
/** /**
* batadv_neigh_ifinfo_free_ref - decrement the refcounter and possibly free * batadv_neigh_ifinfo_free_ref - decrement the refcounter and possibly release
* the neigh_ifinfo * the neigh_ifinfo
* @neigh_ifinfo: the neigh_ifinfo object to release * @neigh_ifinfo: the neigh_ifinfo object to release
*/ */
void batadv_neigh_ifinfo_free_ref(struct batadv_neigh_ifinfo *neigh_ifinfo) void batadv_neigh_ifinfo_free_ref(struct batadv_neigh_ifinfo *neigh_ifinfo)
{ {
if (atomic_dec_and_test(&neigh_ifinfo->refcount)) if (atomic_dec_and_test(&neigh_ifinfo->refcount))
call_rcu(&neigh_ifinfo->rcu, batadv_neigh_ifinfo_free_rcu); batadv_neigh_ifinfo_release(neigh_ifinfo);
} }
/** /**
...@@ -202,7 +188,7 @@ static void batadv_neigh_node_free_rcu(struct rcu_head *rcu) ...@@ -202,7 +188,7 @@ static void batadv_neigh_node_free_rcu(struct rcu_head *rcu)
hlist_for_each_entry_safe(neigh_ifinfo, node_tmp, hlist_for_each_entry_safe(neigh_ifinfo, node_tmp,
&neigh_node->ifinfo_list, list) { &neigh_node->ifinfo_list, list) {
batadv_neigh_ifinfo_free_ref_now(neigh_ifinfo); batadv_neigh_ifinfo_free_ref(neigh_ifinfo);
} }
batadv_hardif_free_ref_now(neigh_node->if_incoming); batadv_hardif_free_ref_now(neigh_node->if_incoming);
......
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