From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Westphal Subject: Re: [PATCH nf-next 3/3] netfilter: replace list_head with single linked list Date: Sat, 9 Jul 2016 01:30:38 +0200 Message-ID: <20160708233038.GA2067@breakpoint.cc> References: <1467321575-6107-1-git-send-email-aconole@bytheb.org> <1467321575-6107-4-git-send-email-aconole@bytheb.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org To: Aaron Conole Return-path: Content-Disposition: inline In-Reply-To: <1467321575-6107-4-git-send-email-aconole@bytheb.org> Sender: netdev-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org Aaron Conole wrote: > --- a/net/netfilter/core.c > +++ b/net/netfilter/core [..] > +#define nf_entry_dereference(e) \ > + rcu_dereference_protected(e, lockdep_is_held(&nf_hook_mutex)) > > -static struct list_head *nf_find_hook_list(struct net *net, > - const struct nf_hook_ops *reg) > +static struct nf_hook_entry *nf_find_hook_list(struct net *net, > + const struct nf_hook_ops *reg) > { > - struct list_head *hook_list = NULL; > + struct nf_hook_entry *hook_list = NULL; > > if (reg->pf != NFPROTO_NETDEV) > - hook_list = &net->nf.hooks[reg->pf][reg->hooknum]; > + hook_list = rcu_dereference(net->nf.hooks[reg->pf] > + [reg->hooknum]); > else if (reg->hooknum == NF_NETDEV_INGRESS) { > #ifdef CONFIG_NETFILTER_INGRESS > if (reg->dev && dev_net(reg->dev) == net) > - hook_list = ®->dev->nf_hooks_ingress; > + hook_list = > + rcu_dereference(reg->dev->nf_hooks_ingress); Both of these should use nf_entry_dereference() to avoid the lockdep splat reported by kbuild robot: net/netfilter/core.c:75 suspicious rcu_dereference_check() usage! 2 locks held by swapper/1: #0: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 #1: (nf_hook_mutex){+.+...}, at: [] nf_register_net_hook+0xcb/0x240