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authorJohannes Weiner <jweiner@fb.com>2016-09-19 14:44:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-09-19 15:36:17 -0700
commitd979a39d7242e0601bf9b60e89628fb8ac577179 (patch)
treef790aa92992c9bf54088de8d8bf0fa275252ab1f
parentdb2ba40c277dc545bab531671c3f45ac0afea6f8 (diff)
cgroup: duplicate cgroup reference when cloning sockets
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@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Tejun Heo <tj@kernel.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: <stable@vger.kernel.org> [4.5+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/cgroup.c6
-rw-r--r--net/core/sock.c5
2 files changed, 10 insertions, 1 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index d1c51b7f5221..5e8dab5bf9ad 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -6270,6 +6270,12 @@ void cgroup_sk_alloc(struct sock_cgroup_data *skcd)
if (cgroup_sk_alloc_disabled)
return;
+ /* Socket clone path */
+ if (skcd->val) {
+ cgroup_get(sock_cgroup_ptr(skcd));
+ return;
+ }
+
rcu_read_lock();
while (true) {
diff --git a/net/core/sock.c b/net/core/sock.c
index 25dab8b60223..fd7b41edf1ce 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1362,7 +1362,6 @@ static struct sock *sk_prot_alloc(struct proto *prot, gfp_t priority,
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, int family, gfp_t priority,
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 sock *sk, const gfp_t priority)
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)