From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: Re: [bug] __nf_ct_refresh_acct(): WARNING: at lib/list_debug.c:30 __list_add+0x7d/0xad() Date: Wed, 17 Jun 2009 13:38:37 +0200 Message-ID: <4A38D5BD.2040502@trash.net> References: <20090615.050449.144947903.davem@davemloft.net> <20090616091538.GA4184@elte.hu> <20090616.034752.226811527.davem@davemloft.net> <20090616105304.GA3579@elte.hu> <20090616122415.GA16630@elte.hu> <20090617092152.GA17449@elte.hu> <4A38C2F3.3000009@gmail.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------070703010704080004050304" Cc: Ingo Molnar , David Miller , Thomas Gleixner , torvalds@linux-foundation.org, akpm@linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Eric Dumazet Return-path: Received: from stinky.trash.net ([213.144.137.162]:64627 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754446AbZFQLih (ORCPT ); Wed, 17 Jun 2009 07:38:37 -0400 In-Reply-To: <4A38C2F3.3000009@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: This is a multi-part message in MIME format. --------------070703010704080004050304 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Eric Dumazet wrote: > IPS_CONFIRMED_BIT is set under nf_conntrack_lock (in __nf_conntrack_confirm()), > we probably want to add a synchronisation under ct->lock as well, > or __nf_ct_refresh_acct() could set ct->timeout.expires to extra_jiffies, > while a different cpu could confirm the conntrack. Before the conntrack is confirmed, it is exclusively handled by a single CPU. I agree that we need to make sure the IPS_CONFIRMED_BIT is visible before we add the conntrack to the hash table since the lookup is lockless, but simply moving the set_bit before the hash insertion should be fine I think. --------------070703010704080004050304 Content-Type: text/plain; name="x" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="x" diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 5f72b94..22755fa 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -425,6 +425,7 @@ __nf_conntrack_confirm(struct sk_buff *skb) /* Remove from unconfirmed list */ hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); + set_bit(IPS_CONFIRMED_BIT, &ct->status); __nf_conntrack_hash_insert(ct, hash, repl_hash); /* Timer relative to confirmation time, not original setting time, otherwise we'd get timer wrap in @@ -432,7 +433,6 @@ __nf_conntrack_confirm(struct sk_buff *skb) ct->timeout.expires += jiffies; add_timer(&ct->timeout); atomic_inc(&ct->ct_general.use); - set_bit(IPS_CONFIRMED_BIT, &ct->status); NF_CT_STAT_INC(net, insert); spin_unlock_bh(&nf_conntrack_lock); help = nfct_help(ct); --------------070703010704080004050304--