[3.19.y-ckt stable] Patch "sit: fix sit0 percpu double allocations" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    sit: fix sit0 percpu double allocations

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt11.

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

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From f36f4ca419ba11542fbf789b57230fbfa6b3e8f4 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet at google.com>
Date: Mon, 2 Nov 2015 17:08:19 -0800
Subject: sit: fix sit0 percpu double allocations

[ Upstream commit 4ece9009774596ee3df0acba65a324b7ea79387c ]

sit0 device allocates its percpu storage twice :
- One time in ipip6_tunnel_init()
- One time in ipip6_fb_tunnel_init()

Thus we leak 48 bytes per possible cpu per network namespace dismantle.

ipip6_fb_tunnel_init() can be much simpler and does not
return an error, and should be called after register_netdev()

Note that ipip6_tunnel_clone_6rd() also needs to be called
after register_netdev() (calling ipip6_tunnel_init())

Fixes: ebe084aafb7e ("sit: Use ipip6_tunnel_init as the ndo_init function.")
Signed-off-by: Eric Dumazet <edumazet at google.com>
Reported-by: Dmitry Vyukov <dvyukov at google.com>
Cc: Steffen Klassert <steffen.klassert at secunet.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/ipv6/sit.c | 26 ++++----------------------
 1 file changed, 4 insertions(+), 22 deletions(-)

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index cdbfe5a..eb3ea58 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1395,34 +1395,20 @@ static int ipip6_tunnel_init(struct net_device *dev)
 	return 0;
 }

-static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
+static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
 	struct iphdr *iph = &tunnel->parms.iph;
 	struct net *net = dev_net(dev);
 	struct sit_net *sitn = net_generic(net, sit_net_id);

-	tunnel->dev = dev;
-	tunnel->net = dev_net(dev);
-
 	iph->version		= 4;
 	iph->protocol		= IPPROTO_IPV6;
 	iph->ihl		= 5;
 	iph->ttl		= 64;

-	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
-	if (!dev->tstats)
-		return -ENOMEM;
-
-	tunnel->dst_cache = alloc_percpu(struct ip_tunnel_dst);
-	if (!tunnel->dst_cache) {
-		free_percpu(dev->tstats);
-		return -ENOMEM;
-	}
-
 	dev_hold(dev);
 	rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
-	return 0;
 }

 static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[])
@@ -1832,23 +1818,19 @@ static int __net_init sit_init_net(struct net *net)
 	 */
 	sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;

-	err = ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
-	if (err)
-		goto err_dev_free;
-
-	ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
 	err = register_netdev(sitn->fb_tunnel_dev);
 	if (err)
 		goto err_reg_dev;

+	ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
+	ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
+
 	t = netdev_priv(sitn->fb_tunnel_dev);

 	strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
 	return 0;

 err_reg_dev:
-	dev_put(sitn->fb_tunnel_dev);
-err_dev_free:
 	ipip6_dev_free(sitn->fb_tunnel_dev);
 err_alloc_dev:
 	return err;
--
1.9.1