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batman-adv: Drop immediate neigh_ifinfo free function

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[ Upstream commit ae3e1e36e3 ]

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: 89652331c0 ("batman-adv: split tq information in neigh_node struct")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sven Eckelmann
2016-01-05 12:06:24 +01:00
committed by Greg Kroah-Hartman
parent 31459b9b45
commit 568f95d027
1 changed files with 10 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
net/batman-adv/originator.c
View File

@@ -163,42 +163,28 @@ err:
}
/**
* batadv_neigh_ifinfo_free_rcu - free the neigh_ifinfo object
* @rcu: rcu pointer of the neigh_ifinfo object
*/
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)
* batadv_neigh_ifinfo_release - release neigh_ifinfo from lists and queue for
* free after rcu grace period
* @neigh_ifinfo: the neigh_ifinfo object to release
*/
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))
batadv_neigh_ifinfo_free_rcu(&neigh_ifinfo->rcu);
if (neigh_ifinfo->if_outgoing != BATADV_IF_DEFAULT)
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
* @neigh_ifinfo: the neigh_ifinfo object to release
*/
void batadv_neigh_ifinfo_free_ref(struct batadv_neigh_ifinfo *neigh_ifinfo)
{
if (atomic_dec_and_test(&neigh_ifinfo->refcount))
call_rcu(&neigh_ifinfo->rcu, batadv_neigh_ifinfo_free_rcu);
batadv_neigh_ifinfo_release(neigh_ifinfo);
}
/**
@@ -217,7 +203,7 @@ static void batadv_neigh_node_free_rcu(struct rcu_head *rcu)
hlist_for_each_entry_safe(neigh_ifinfo, node_tmp,
&neigh_node->ifinfo_list, list) {
batadv_neigh_ifinfo_free_ref_now(neigh_ifinfo);
batadv_neigh_ifinfo_free_ref(neigh_ifinfo);
}
if (bao->bat_neigh_free)