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[3.5.y.z,extended,stable] Patch "vlan: fix a race in egress prio management" has been added to staging queue

Message ID 1374763335-18452-1-git-send-email-luis.henriques@canonical.com
State New
Headers show

Commit Message

Luis Henriques July 25, 2013, 2:42 p.m. UTC 
This is a note to let you know that I have just added a patch titled

    vlan: fix a race in egress prio management

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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From 796007b03a5267f4781b21a626b257c785f2c440 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Thu, 18 Jul 2013 09:35:10 -0700
Subject: [PATCH] vlan: fix a race in egress prio management

commit 3e3aac497513c669e1c62c71e1d552ea85c1d974 upstream.

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: Luis Henriques <luis.henriques@canonical.com>
---
 net/8021q/vlan_dev.c | 7 +++++++
 1 file changed, 7 insertions(+)

--
1.8.1.2
diff mbox

Patch

diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index 7005e08..b8cf84e 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -73,6 +73,8 @@  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_priv(dev)->egress_priority_map[(skb->priority & 0xF)];
 	while (mp) {
 		if (mp->priority == skb->priority) {
@@ -235,6 +237,11 @@  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++;