Patch "ipv6: Don't depend on per socket memory for neighbour discovery messages" has been added to the 3.10-stable tree

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This is a note to let you know that I've just added the patch titled

    ipv6: Don't depend on per socket memory for neighbour discovery messages

to the 3.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ipv6-don-t-depend-on-per-socket-memory-for-neighbour-discovery-messages.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 6cdb64d5f00491d0a515a61e233d049ca7f47c9e Mon Sep 17 00:00:00 2001
From: Thomas Graf <tgraf@xxxxxxx>
Date: Tue, 3 Sep 2013 13:37:01 +0200
Subject: ipv6: Don't depend on per socket memory for neighbour discovery messages

From: Thomas Graf <tgraf@xxxxxxx>

[ Upstream commit 25a6e6b84fba601eff7c28d30da8ad7cfbef0d43 ]

Allocating skbs when sending out neighbour discovery messages
currently uses sock_alloc_send_skb() based on a per net namespace
socket and thus share a socket wmem buffer space.

If a netdevice is temporarily unable to transmit due to carrier
loss or for other reasons, the queued up ndisc messages will cosnume
all of the wmem space and will thus prevent from any more skbs to
be allocated even for netdevices that are able to transmit packets.

The number of neighbour discovery messages sent is very limited,
use of alloc_skb() bypasses the socket wmem buffer size enforcement
while the manual call to skb_set_owner_w() maintains the socket
reference needed for the IPv6 output path.

This patch has orginally been posted by Eric Dumazet in a modified
form.

Signed-off-by: Thomas Graf <tgraf@xxxxxxx>
Cc: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Cc: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Cc: Stephen Warren <swarren@xxxxxxxxxxxxx>
Cc: Fabio Estevam <festevam@xxxxxxxxx>
Tested-by: Fabio Estevam <fabio.estevam@xxxxxxxxxxxxx>
Tested-by: Stephen Warren <swarren@xxxxxxxxxx>
Acked-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ipv6/ndisc.c |   14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -372,14 +372,11 @@ static struct sk_buff *ndisc_alloc_skb(s
 	int tlen = dev->needed_tailroom;
 	struct sock *sk = dev_net(dev)->ipv6.ndisc_sk;
 	struct sk_buff *skb;
-	int err;
 
-	skb = sock_alloc_send_skb(sk,
-				  hlen + sizeof(struct ipv6hdr) + len + tlen,
-				  1, &err);
+	skb = alloc_skb(hlen + sizeof(struct ipv6hdr) + len + tlen, GFP_ATOMIC);
 	if (!skb) {
-		ND_PRINTK(0, err, "ndisc: %s failed to allocate an skb, err=%d\n",
-			  __func__, err);
+		ND_PRINTK(0, err, "ndisc: %s failed to allocate an skb\n",
+			  __func__);
 		return NULL;
 	}
 
@@ -389,6 +386,11 @@ static struct sk_buff *ndisc_alloc_skb(s
 	skb_reserve(skb, hlen + sizeof(struct ipv6hdr));
 	skb_reset_transport_header(skb);
 
+	/* Manually assign socket ownership as we avoid calling
+	 * sock_alloc_send_pskb() to bypass wmem buffer limits
+	 */
+	skb_set_owner_w(skb, sk);
+
 	return skb;
 }
 


Patches currently in stable-queue which might be from tgraf@xxxxxxx are

queue-3.10/ipv6-don-t-depend-on-per-socket-memory-for-neighbour-discovery-messages.patch
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