Hello David,
these are two small fixes intended for your net tree.
Patch 1 prevents a lockdep splat from appearing along the shutdown path due to a missing lock in mcast_free(), by Simon Wunderlich.
Patch 2 fixes a new feature introduced in 4.5 by ensuring that a batadv_hardif_neigh_node object is free'd only when it is no longer used in any context, by Sven Eckelmann.
Please pull or let me know of any issue. Thanks a lot, Antonio
The following changes since commit f1640c3ddeec12804bc9a21feee85fc15aca95f6:
bgmac: fix a missing check for build_skb (2016-01-13 00:24:14 -0500)
are available in the git repository at:
git://git.open-mesh.org/linux-merge.git tags/batman-adv-fix-for-davem
for you to fetch changes up to bab7c6c3deac70966a3000402c0ea6d0c20edd15:
batman-adv: Fix list removal of batadv_hardif_neigh_node (2016-01-13 19:28:27 +0800)
---------------------------------------------------------------- Included bugfixes: - avoid freeing batadv_hardif_neigh_node when still in use in other contexts - prevent lockdep splat in mcast_free during shutdown
---------------------------------------------------------------- Simon Wunderlich (1): batman-adv: fix lockdep splat when doing mcast_free
Sven Eckelmann (1): batman-adv: Fix list removal of batadv_hardif_neigh_node
net/batman-adv/multicast.c | 2 ++ net/batman-adv/originator.c | 18 ++++++++++++------ 2 files changed, 14 insertions(+), 6 deletions(-)
From: Simon Wunderlich simon@open-mesh.com
While testing, we got something like this:
WARNING: CPU: 0 PID: 238 at net/batman-adv/multicast.c:142 batadv_mcast_mla_tt_retract+0x94/0x205 [batman_adv]() [...] Call Trace: [<ffffffff815fc597>] dump_stack+0x4b/0x64 [<ffffffff810b34dc>] warn_slowpath_common+0xbc/0x120 [<ffffffffa0024ec5>] ? batadv_mcast_mla_tt_retract+0x94/0x205 [batman_adv] [<ffffffff810b3705>] warn_slowpath_null+0x15/0x20 [<ffffffffa0024ec5>] batadv_mcast_mla_tt_retract+0x94/0x205 [batman_adv] [<ffffffffa00273fe>] batadv_mcast_free+0x36/0x39 [batman_adv] [<ffffffffa0020c77>] batadv_mesh_free+0x7d/0x13f [batman_adv] [<ffffffffa0036a6b>] batadv_softif_free+0x15/0x25 [batman_adv] [...]
Signed-off-by: Simon Wunderlich simon@open-mesh.com Signed-off-by: Marek Lindner mareklindner@neomailbox.ch Signed-off-by: Antonio Quartulli a@unstable.cc --- net/batman-adv/multicast.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c index eb76386f8d4b..75fa5013af72 100644 --- a/net/batman-adv/multicast.c +++ b/net/batman-adv/multicast.c @@ -802,7 +802,9 @@ void batadv_mcast_free(struct batadv_priv *bat_priv) batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_MCAST, 1); batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_MCAST, 1);
+ spin_lock_bh(&bat_priv->tt.commit_lock); batadv_mcast_mla_tt_retract(bat_priv, NULL); + spin_unlock_bh(&bat_priv->tt.commit_lock); }
/**
From: Sven Eckelmann sven@narfation.org
The neigh_list with batadv_hardif_neigh_node objects is accessed with only rcu_read_lock in batadv_hardif_neigh_get and batadv_iv_neigh_print. Thus it is not allowed to kfree the object before the rcu grace period ends (which may still protects context accessing this object). Therefore the object has first to be removed from the neigh_list and then it has either wait with synchronize_rcu or call_rcu till the grace period ends before it can be freed.
Fixes: cef63419f7db ("batman-adv: add list of unique single hop neighbors per hard-interface") Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Marek Lindner mareklindner@neomailbox.ch Signed-off-by: Antonio Quartulli a@unstable.cc --- net/batman-adv/originator.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c index 3c782a33bdac..ae6d18cafc5a 100644 --- a/net/batman-adv/originator.c +++ b/net/batman-adv/originator.c @@ -211,10 +211,6 @@ static void batadv_hardif_neigh_free_rcu(struct rcu_head *rcu)
hardif_neigh = container_of(rcu, struct batadv_hardif_neigh_node, rcu);
- spin_lock_bh(&hardif_neigh->if_incoming->neigh_list_lock); - hlist_del_init_rcu(&hardif_neigh->list); - spin_unlock_bh(&hardif_neigh->if_incoming->neigh_list_lock); - batadv_hardif_free_ref_now(hardif_neigh->if_incoming); kfree(hardif_neigh); } @@ -227,8 +223,13 @@ static void batadv_hardif_neigh_free_rcu(struct rcu_head *rcu) static void batadv_hardif_neigh_free_now(struct batadv_hardif_neigh_node *hardif_neigh) { - if (atomic_dec_and_test(&hardif_neigh->refcount)) + if (atomic_dec_and_test(&hardif_neigh->refcount)) { + spin_lock_bh(&hardif_neigh->if_incoming->neigh_list_lock); + hlist_del_init_rcu(&hardif_neigh->list); + spin_unlock_bh(&hardif_neigh->if_incoming->neigh_list_lock); + batadv_hardif_neigh_free_rcu(&hardif_neigh->rcu); + } }
/** @@ -238,8 +239,13 @@ batadv_hardif_neigh_free_now(struct batadv_hardif_neigh_node *hardif_neigh) */ void batadv_hardif_neigh_free_ref(struct batadv_hardif_neigh_node *hardif_neigh) { - if (atomic_dec_and_test(&hardif_neigh->refcount)) + if (atomic_dec_and_test(&hardif_neigh->refcount)) { + spin_lock_bh(&hardif_neigh->if_incoming->neigh_list_lock); + hlist_del_init_rcu(&hardif_neigh->list); + spin_unlock_bh(&hardif_neigh->if_incoming->neigh_list_lock); + call_rcu(&hardif_neigh->rcu, batadv_hardif_neigh_free_rcu); + } }
/**
From: Antonio Quartulli a@unstable.cc Date: Thu, 14 Jan 2016 01:51:52 +0800
these are two small fixes intended for your net tree.
Patch 1 prevents a lockdep splat from appearing along the shutdown path due to a missing lock in mcast_free(), by Simon Wunderlich.
Patch 2 fixes a new feature introduced in 4.5 by ensuring that a batadv_hardif_neigh_node object is free'd only when it is no longer used in any context, by Sven Eckelmann.
Please pull or let me know of any issue.
Pulled, thanks!
b.a.t.m.a.n@lists.open-mesh.org
-
Antonio Quartulli -
David Miller