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authorEric Dumazet <edumazet@google.com>2013-07-18 09:35:10 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-07-28 16:18:43 -0700
commitf45a0233de990dc788371b54f23a8986a23bfa4a (patch)
tree2799d6fd3b02c675d6a650910f291ab292edbd62
parent8956c3efefa2a61df16a47ba4f159e3d49717858 (diff)
vlan: fix a race in egress prio management
[ Upstream commit 3e3aac497513c669e1c62c71e1d552ea85c1d974 ] egress_priority_map[] hash table updates are protected by rtnl, and we never remove elements until device is dismantled. We have to make sure that before inserting an new element in hash table, all its fields are committed to memory or else another cpu could find corrupt values and crash. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/8021q/vlan_dev.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index d54845618c2a..b172407bf0e0 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -70,6 +70,8 @@ vlan_dev_get_egress_qos_mask(struct net_device *dev, struct sk_buff *skb)
{
struct vlan_priority_tci_mapping *mp;
+ smp_rmb(); /* coupled with smp_wmb() in vlan_dev_set_egress_priority() */
+
mp = vlan_dev_info(dev)->egress_priority_map[(skb->priority & 0xF)];
while (mp) {
if (mp->priority == skb->priority) {
@@ -230,6 +232,11 @@ int vlan_dev_set_egress_priority(const struct net_device *dev,
np->next = mp;
np->priority = skb_prio;
np->vlan_qos = vlan_qos;
+ /* Before inserting this element in hash table, make sure all its fields
+ * are committed to memory.
+ * coupled with smp_rmb() in vlan_dev_get_egress_qos_mask()
+ */
+ smp_wmb();
vlan->egress_priority_map[skb_prio & 0xF] = np;
if (vlan_qos)
vlan->nr_egress_mappings++;