Commit 9f1c2674 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: e994b2f0

 ("tcp: do not lock listener to process SYN packets")
Signed-off-by: default avatarEric Dumazet <>
Cc: Johannes Weiner <>
Cc: Tejun Heo <>
Signed-off-by: default avatarDavid S. Miller <>
parent 529a86e0
......@@ -5828,21 +5828,6 @@ void mem_cgroup_sk_alloc(struct sock *sk)
if (!mem_cgroup_sockets_enabled)
* 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) {
memcg = mem_cgroup_from_task(current);
if (memcg == root_mem_cgroup)
......@@ -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);
......@@ -475,6 +475,7 @@ struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern)
if (req)
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