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From: Antonio Quartulli
To: davem@davemloft.net
Date: Tue, 16 Feb 2016 23:01:27 +0800
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Cc: netdev@vger.kernel.org, b.a.t.m.a.n@lists.open-mesh.org,
Antonio Quartulli ,
Marek Lindner
Subject: [B.A.T.M.A.N.] [PATCH 2/3] batman-adv: Only put orig_node_vlan list
reference when removed
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From: Sven Eckelmann
The batadv_orig_node_vlan reference counter in batadv_tt_global_size_mod
can only be reduced when the list entry was actually removed. Otherwise the
reference counter may reach zero when batadv_tt_global_size_mod is called
from two different contexts for the same orig_node_vlan but only one
context is actually removing the entry from the list.
The release function for this orig_node_vlan is not called inside the
vlan_list_lock spinlock protected region because the function
batadv_tt_global_size_mod still holds a orig_node_vlan reference for the
object pointer on the stack. Thus the actual release function (when
required) will be called only at the end of the function.
Fixes: 7ea7b4a14275 ("batman-adv: make the TT CRC logic VLAN specific")
Signed-off-by: Sven Eckelmann
Signed-off-by: Marek Lindner
Signed-off-by: Antonio Quartulli
---
net/batman-adv/translation-table.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index cdfc85fa2743..0e80fd1461ab 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -303,9 +303,11 @@ static void batadv_tt_global_size_mod(struct batadv_orig_node *orig_node,
if (atomic_add_return(v, &vlan->tt.num_entries) == 0) {
spin_lock_bh(&orig_node->vlan_list_lock);
- hlist_del_init_rcu(&vlan->list);
+ if (!hlist_unhashed(&vlan->list)) {
+ hlist_del_init_rcu(&vlan->list);
+ batadv_orig_node_vlan_free_ref(vlan);
+ }
spin_unlock_bh(&orig_node->vlan_list_lock);
- batadv_orig_node_vlan_free_ref(vlan);
}
batadv_orig_node_vlan_free_ref(vlan);