This is a note to let you know that I've just added the patch titled
cgroup: duplicate cgroup reference when cloning sockets
to the 4.7-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:
cgroup-duplicate-cgroup-reference-when-cloning-sockets.patch
and it can be found in the queue-4.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d979a39d7242e0601bf9b60e89628fb8ac577179 Mon Sep 17 00:00:00 2001
From: Johannes Weiner <jweiner@xxxxxx>
Date: Mon, 19 Sep 2016 14:44:38 -0700
Subject: cgroup: duplicate cgroup reference when cloning sockets
From: Johannes Weiner <jweiner@xxxxxx>
commit d979a39d7242e0601bf9b60e89628fb8ac577179 upstream.
When a socket is cloned, the associated sock_cgroup_data is duplicated
but not its reference on the cgroup. As a result, the cgroup reference
count will underflow when both sockets are destroyed later on.
Fixes: bd1060a1d671 ("sock, cgroup: add sock->sk_cgroup")
Link: http://lkml.kernel.org/r/20160914194846.11153-2-hannes@xxxxxxxxxxx
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/cgroup.c | 6 ++++++
net/core/sock.c | 5 ++++-
2 files changed, 10 insertions(+), 1 deletion(-)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -6240,6 +6240,12 @@ void cgroup_sk_alloc(struct sock_cgroup_
if (cgroup_sk_alloc_disabled)
return;
+ /* Socket clone path */
+ if (skcd->val) {
+ cgroup_get(sock_cgroup_ptr(skcd));
+ return;
+ }
+
rcu_read_lock();
while (true) {
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1362,7 +1362,6 @@ static struct sock *sk_prot_alloc(struct
if (!try_module_get(prot->owner))
goto out_free_sec;
sk_tx_queue_clear(sk);
- cgroup_sk_alloc(&sk->sk_cgrp_data);
}
return sk;
@@ -1422,6 +1421,7 @@ struct sock *sk_alloc(struct net *net, i
sock_net_set(sk, net);
atomic_set(&sk->sk_wmem_alloc, 1);
+ cgroup_sk_alloc(&sk->sk_cgrp_data);
sock_update_classid(&sk->sk_cgrp_data);
sock_update_netprioidx(&sk->sk_cgrp_data);
}
@@ -1566,6 +1566,9 @@ struct sock *sk_clone_lock(const struct
newsk->sk_priority = 0;
newsk->sk_incoming_cpu = raw_smp_processor_id();
atomic64_set(&newsk->sk_cookie, 0);
+
+ cgroup_sk_alloc(&newsk->sk_cgrp_data);
+
/*
* Before updating sk_refcnt, we must commit prior changes to memory
* (Documentation/RCU/rculist_nulls.txt for details)
Patches currently in stable-queue which might be from jweiner@xxxxxx are
queue-4.7/mm-memcontrol-make-per-cpu-charge-cache-irq-safe-for-socket-accounting.patch
queue-4.7/cgroup-duplicate-cgroup-reference-when-cloning-sockets.patch
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