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| author | Johannes Weiner <jweiner@fb.com> | 2016-09-19 14:44:38 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-30 10:12:44 +0200 |
| commit | 02d35700208c7a13a75405018222646502608961 (patch) | |
| tree | 89f4403991036af36b6cbf825893e8c79c7226a1 | |
| parent | 0d91b17b239118104998d5a3f0da016c93be7b69 (diff) | |
| download | lwn-02d35700208c7a13a75405018222646502608961.tar.gz lwn-02d35700208c7a13a75405018222646502608961.zip | |
cgroup: duplicate cgroup reference when cloning sockets
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@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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/cgroup.c | 6 | ||||
| -rw-r--r-- | net/core/sock.c | 5 |
2 files changed, 10 insertions, 1 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index e0be49fc382f..129a7ca5f159 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -6240,6 +6240,12 @@ 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) |