[4.2.y-ckt stable] Patch "fou: clean up socket with kfree_rcu" has been added to staging queue

Kamal Mostafa kamal at canonical.com
Tue Jan 5 19:01:30 UTC 2016


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

    fou: clean up socket with kfree_rcu

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt1.

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

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 002b295efff2a6324621c0f56b0eacda273fb631 Mon Sep 17 00:00:00 2001
From: Hannes Frederic Sowa <hannes at stressinduktion.org>
Date: Tue, 15 Dec 2015 21:01:53 +0100
Subject: fou: clean up socket with kfree_rcu

[ Upstream commit 3036facbb7be3a169e35be3b271162b0fa564a2d ]

fou->udp_offloads is managed by RCU. As it is actually included inside
the fou sockets, we cannot let the memory go out of scope before a grace
period. We either can synchronize_rcu or switch over to kfree_rcu to
manage the sockets. kfree_rcu seems appropriate as it is used by vxlan
and geneve.

Fixes: 23461551c00628c ("fou: Support for foo-over-udp RX path")
Cc: Tom Herbert <tom at herbertland.com>
Signed-off-by: Hannes Frederic Sowa <hannes at stressinduktion.org>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/ipv4/fou.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index 34968cd..4b67937 100644
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -24,6 +24,7 @@ struct fou {
 	u16 type;
 	struct udp_offload udp_offloads;
 	struct list_head list;
+	struct rcu_head rcu;
 };

 #define FOU_F_REMCSUM_NOPARTIAL BIT(0)
@@ -421,7 +422,7 @@ static void fou_release(struct fou *fou)
 	list_del(&fou->list);
 	udp_tunnel_sock_release(sock);

-	kfree(fou);
+	kfree_rcu(fou, rcu);
 }

 static int fou_encap_init(struct sock *sk, struct fou *fou, struct fou_cfg *cfg)
--
1.9.1





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