From edbe69ef2c90fc86998a74b08319a01c508bd497 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Fri, 2 Feb 2018 15:26:57 +0000 Subject: Revert "defer call to mem_cgroup_sk_alloc()" This patch effectively reverts commit 9f1c2674b328 ("net: memcontrol: defer call to mem_cgroup_sk_alloc()"). Moving mem_cgroup_sk_alloc() to the inet_csk_accept() completely breaks memcg socket memory accounting, as packets received before memcg pointer initialization are not accounted and are causing refcounting underflow on socket release. Actually the free-after-use problem was fixed by commit c0576e397508 ("net: call cgroup_sk_alloc() earlier in sk_clone_lock()") for the cgroup pointer. So, let's revert it and call mem_cgroup_sk_alloc() just before cgroup_sk_alloc(). This is safe, as we hold a reference to the socket we're cloning, and it holds a reference to the memcg. Also, let's drop BUG_ON(mem_cgroup_is_root()) check from mem_cgroup_sk_alloc(). I see no reasons why bumping the root memcg counter is a good reason to panic, and there are no realistic ways to hit it. Signed-off-by: Roman Gushchin Cc: Eric Dumazet Cc: David S. Miller Cc: Johannes Weiner Cc: Tejun Heo Signed-off-by: David S. Miller --- net/core/sock.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'net/core') diff --git a/net/core/sock.c b/net/core/sock.c index 1033f8ab0547..e50e7b3f2223 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1683,16 +1683,13 @@ 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; atomic_set(&newsk->sk_zckey, 0); sock_reset_flag(newsk, SOCK_DONE); + mem_cgroup_sk_alloc(newsk); cgroup_sk_alloc(&newsk->sk_cgrp_data); rcu_read_lock(); -- cgit v1.2.3