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* [B.A.T.M.A.N.] [PATCH v2 01/30] batman-adv: Fix list removal of batadv_hardif_neigh_node
@ 2015-12-20 13:17 Sven Eckelmann
  2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 02/30] batman-adv: Avoid recursive call_rcu for batadv_bla_claim Sven Eckelmann
                   ` (30 more replies)
  0 siblings, 31 replies; 42+ messages in thread
From: Sven Eckelmann @ 2015-12-20 13:17 UTC (permalink / raw)
  To: b.a.t.m.a.n

The neigh_list with batadv_hardif_neigh_node objects is accessed with only
rcu_read_lock in batadv_neigh_node_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: fed2826b490c ("batman-adv: add list of unique single hop neighbors per hard-interface")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
v2:
 - split patchset into fixes and kref migration to make it easier when the
   decision is made where each patch will be applied

 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 00b0437..2681c7d 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -217,10 +217,6 @@ 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);
 }
@@ -233,8 +229,13 @@ 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);
+	}
 }
 
 /**
@@ -244,8 +245,13 @@ 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);
+	}
 }
 
 /**
-- 
2.6.4


^ permalink raw reply related	[flat|nested] 42+ messages in thread

end of thread, other threads:[~2016-01-05  9:18 UTC | newest]

Thread overview: 42+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-12-20 13:17 [B.A.T.M.A.N.] [PATCH v2 01/30] batman-adv: Fix list removal of batadv_hardif_neigh_node Sven Eckelmann
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 02/30] batman-adv: Avoid recursive call_rcu for batadv_bla_claim Sven Eckelmann
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 03/30] batman-adv: Avoid recursive call_rcu for batadv_nc_node Sven Eckelmann
2016-01-04 16:04   ` Linus Lüssing
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 04/30] batman-adv: Drop immediate orig_node free function Sven Eckelmann
2016-01-04 16:32   ` Linus Lüssing
2016-01-04 16:47   ` Linus Lüssing
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 05/30] batman-adv: Drop immediate batadv_orig_ifinfo " Sven Eckelmann
2016-01-04 18:59   ` Linus Lüssing
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 06/30] batman-adv: Drop immediate batadv_neigh_node " Sven Eckelmann
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 07/30] batman-adv: Drop immediate batadv_hardif_neigh_node " Sven Eckelmann
2016-01-05  1:31   ` Linus Lüssing
2016-01-05  1:50     ` Linus Lüssing
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 08/30] batman-adv: Drop immediate neigh_ifinfo " Sven Eckelmann
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 09/30] batman-adv: Drop immediate batadv_hard_iface " Sven Eckelmann
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 10/30] batman-adv: Drop reference to netdevice on last reference Sven Eckelmann
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 11/30] batman-adv: Add compatibility code for kref_get_unless_zero Sven Eckelmann
2015-12-31 23:14   ` [B.A.T.M.A.N.] [PATCH v3 " Sven Eckelmann
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 12/30] batman-adv: Convert batadv_hardif_neigh_node to kref Sven Eckelmann
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 13/30] batman-adv: Convert batadv_gw_node " Sven Eckelmann
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 14/30] batman-adv: Convert batadv_softif_vlan " Sven Eckelmann
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 15/30] batman-adv: Convert batadv_bla_backbone_gw " Sven Eckelmann
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 16/30] batman-adv: Convert batadv_bla_claim " Sven Eckelmann
2016-01-05  4:43   ` Linus Lüssing
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 17/30] batman-adv: Convert batadv_nc_node " Sven Eckelmann
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 18/30] batman-adv: Convert batadv_nc_path " Sven Eckelmann
2015-12-20 13:17 ` [B.A.T.M.A.N.] [PATCH v2 19/30] batman-adv: Convert batadv_dat_entry " Sven Eckelmann
2016-01-05  4:45   ` Linus Lüssing
2015-12-20 13:18 ` [B.A.T.M.A.N.] [PATCH v2 20/30] batman-adv: Convert batadv_tvlv_container " Sven Eckelmann
2015-12-20 13:18 ` [B.A.T.M.A.N.] [PATCH v2 21/30] batman-adv: Convert batadv_tvlv_handler " Sven Eckelmann
2015-12-20 13:18 ` [B.A.T.M.A.N.] [PATCH v2 22/30] batman-adv: Convert batadv_tt_orig_list_entry " Sven Eckelmann
2015-12-20 13:18 ` [B.A.T.M.A.N.] [PATCH v2 23/30] batman-adv: Convert batadv_neigh_ifinfo " Sven Eckelmann
2015-12-20 13:18 ` [B.A.T.M.A.N.] [PATCH v2 24/30] batman-adv: Convert batadv_orig_ifinfo " Sven Eckelmann
2015-12-20 13:18 ` [B.A.T.M.A.N.] [PATCH v2 25/30] batman-adv: Convert batadv_neigh_node " Sven Eckelmann
2015-12-20 13:18 ` [B.A.T.M.A.N.] [PATCH v2 26/30] batman-adv: Convert batadv_hard_iface " Sven Eckelmann
2015-12-20 13:18 ` [B.A.T.M.A.N.] [PATCH v2 27/30] batman-adv: Convert batadv_orig_node_vlan " Sven Eckelmann
2015-12-20 13:18 ` [B.A.T.M.A.N.] [PATCH v2 28/30] batman-adv: Convert batadv_orig_node " Sven Eckelmann
2015-12-20 13:18 ` [B.A.T.M.A.N.] [PATCH v2 29/30] batman-adv: Convert batadv_tt_common_entry " Sven Eckelmann
2015-12-20 13:18 ` [B.A.T.M.A.N.] [PATCH v2 30/30] batman-adv: Rename *_free_ref function to *_put Sven Eckelmann
2016-01-04 16:03 ` [B.A.T.M.A.N.] [PATCH v2 01/30] batman-adv: Fix list removal of batadv_hardif_neigh_node Linus Lüssing
2016-01-05  5:02 ` Linus Lüssing
2016-01-05  9:18   ` Sven Eckelmann

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