[B.A.T.M.A.N.] [PATCH-maint 1/2] batman-adv: Only put gw_node list reference when removed
The batadv_gw_node reference counter in batadv_gw_node_update can only be reduced when the list entry was actually removed. Otherwise the reference counter may reach zero when batadv_gw_node_update is called from two different contexts for the same gw_node but only one context is actually removing the entry from the list.
The release function for this gw_node is not called inside the list_lock spinlock protected region because the function batadv_gw_node_update still holds a gw_node 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: 0511575c4d03 ("batman-adv: remove obsolete deleted attribute for gateway node") Signed-off-by: Sven Eckelmann sven@narfation.org --- net/batman-adv/gateway_client.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c index 8350775..c9b8b48 100644 --- a/net/batman-adv/gateway_client.c +++ b/net/batman-adv/gateway_client.c @@ -527,11 +527,12 @@ void batadv_gw_node_update(struct batadv_priv *bat_priv, * gets dereferenced. */ spin_lock_bh(&bat_priv->gw.list_lock); - hlist_del_init_rcu(&gw_node->list); + if (!hlist_unhashed(&gw_node->list)) { + hlist_del_init_rcu(&gw_node->list); + batadv_gw_node_free_ref(gw_node); + } spin_unlock_bh(&bat_priv->gw.list_lock);
- batadv_gw_node_free_ref(gw_node); - curr_gw = batadv_gw_get_selected_gw_node(bat_priv); if (gw_node == curr_gw) batadv_gw_reselect(bat_priv);
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: 21a57f6e7a3b ("batman-adv: make the TT CRC logic VLAN specific") Signed-off-by: Sven Eckelmann sven@narfation.org --- 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 9fcf6bf..7301a92 100644 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -311,9 +311,11 @@ 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);
On Sunday, January 31, 2016 13:28:00 Sven Eckelmann wrote:
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: 21a57f6e7a3b ("batman-adv: make the TT CRC logic VLAN specific") Signed-off-by: Sven Eckelmann sven@narfation.org
net/batman-adv/translation-table.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
Applied in revision ead9389.
Thanks, Marek
On Sunday, January 31, 2016 13:27:59 Sven Eckelmann wrote:
The batadv_gw_node reference counter in batadv_gw_node_update can only be reduced when the list entry was actually removed. Otherwise the reference counter may reach zero when batadv_gw_node_update is called from two different contexts for the same gw_node but only one context is actually removing the entry from the list.
The release function for this gw_node is not called inside the list_lock spinlock protected region because the function batadv_gw_node_update still holds a gw_node 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: 0511575c4d03 ("batman-adv: remove obsolete deleted attribute for gateway node") Signed-off-by: Sven Eckelmann sven@narfation.org
net/batman-adv/gateway_client.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
Applied in revision c215e4e.
Thanks, Marek
b.a.t.m.a.n@lists.open-mesh.org
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Marek Lindner -
Sven Eckelmann