diff options
| author | Eric Dumazet <edumazet@google.com> | 2017-10-08 21:44:51 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-10-09 20:55:01 -0700 |
| commit | 9f1c2674b328a69ab5a9b5a1c52405795ee4163f (patch) | |
| tree | bef7fc6c61201ca2b6d913bab2686a38fda039d2 | |
| parent | 529a86e063e9ff625c4ff247d8aa17d8072444fb (diff) | |
net: memcontrol: defer call to mem_cgroup_sk_alloc()
Instead of calling mem_cgroup_sk_alloc() from BH context,
it is better to call it from inet_csk_accept() in process context.
Not only this removes code in mem_cgroup_sk_alloc(), but it also
fixes a bug since listener might have been dismantled and css_get()
might cause a use-after-free.
Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | mm/memcontrol.c | 15 | ||||
| -rw-r--r-- | net/core/sock.c | 5 | ||||
| -rw-r--r-- | net/ipv4/inet_connection_sock.c | 1 |
3 files changed, 5 insertions, 16 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index d5f3a62887cf..661f046ad318 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5828,21 +5828,6 @@ void mem_cgroup_sk_alloc(struct sock *sk) if (!mem_cgroup_sockets_enabled) return; - /* - * Socket cloning can throw us here with sk_memcg already - * filled. It won't however, necessarily happen from - * process context. So the test for root memcg given - * the current task's memcg won't help us in this case. - * - * Respecting the original socket's memcg is a better - * decision in this case. - */ - if (sk->sk_memcg) { - BUG_ON(mem_cgroup_is_root(sk->sk_memcg)); - css_get(&sk->sk_memcg->css); - return; - } - rcu_read_lock(); memcg = mem_cgroup_from_task(current); if (memcg == root_mem_cgroup) diff --git a/net/core/sock.c b/net/core/sock.c index 23953b741a41..70c6ccbdf49f 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1677,6 +1677,10 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority) newsk->sk_dst_pending_confirm = 0; newsk->sk_wmem_queued = 0; newsk->sk_forward_alloc = 0; + + /* sk->sk_memcg will be populated at accept() time */ + newsk->sk_memcg = NULL; + atomic_set(&newsk->sk_drops, 0); newsk->sk_send_head = NULL; newsk->sk_userlocks = sk->sk_userlocks & ~SOCK_BINDPORT_LOCK; @@ -1714,7 +1718,6 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority) newsk->sk_incoming_cpu = raw_smp_processor_id(); atomic64_set(&newsk->sk_cookie, 0); - mem_cgroup_sk_alloc(newsk); cgroup_sk_alloc(&newsk->sk_cgrp_data); /* diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index c039c937ba90..67aec7a10686 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -475,6 +475,7 @@ struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern) } spin_unlock_bh(&queue->fastopenq.lock); } + mem_cgroup_sk_alloc(newsk); out: release_sock(sk); if (req) |