From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: Re: [PATCH 3/6] netfilter: ctnetlink: use GFP_ATOMIC in all allocations Date: Tue, 6 Mar 2012 15:48:38 +0100 Message-ID: <20120306144838.GA1527@1984> References: <1331032975-5303-1-git-send-email-pablo@netfilter.org> <1331032975-5303-4-git-send-email-pablo@netfilter.org> <1331038221.9504.9.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netfilter-devel@vger.kernel.org, davem@davemloft.net, netdev@vger.kernel.org To: Eric Dumazet Return-path: Received: from mail.us.es ([193.147.175.20]:57755 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759273Ab2CFOsn (ORCPT ); Tue, 6 Mar 2012 09:48:43 -0500 Content-Disposition: inline In-Reply-To: <1331038221.9504.9.camel@edumazet-glaptop> Sender: netfilter-devel-owner@vger.kernel.org List-ID: On Tue, Mar 06, 2012 at 04:50:21AM -0800, Eric Dumazet wrote: > On Tue, 2012-03-06 at 12:22 +0100, pablo@netfilter.org wrote: > > From: Pablo Neira Ayuso > > > > All ctnetlink operations are invoked inside rcu_read_lock > > (see net/netfilter/nfnetlink.c). > > > > Allocations have to be atomic, as RCU requires. > > > > Signed-off-by: Pablo Neira Ayuso > > --- > > net/netfilter/nf_conntrack_netlink.c | 4 ++-- > > 1 files changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c > > index 1068769..867843f 100644 > > --- a/net/netfilter/nf_conntrack_netlink.c > > +++ b/net/netfilter/nf_conntrack_netlink.c > > @@ -1002,7 +1002,7 @@ ctnetlink_get_conntrack(struct sock *ctnl, struct sk_buff *skb, > > ct = nf_ct_tuplehash_to_ctrack(h); > > > > err = -ENOMEM; > > - skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); > > + skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); > > if (skb2 == NULL) { > > nf_ct_put(ct); > > return -ENOMEM; > > @@ -1865,7 +1865,7 @@ ctnetlink_get_expect(struct sock *ctnl, struct sk_buff *skb, > > } > > > > err = -ENOMEM; > > - skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); > > + skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); > > if (skb2 == NULL) { > > nf_ct_expect_put(exp); > > goto out; > > This cant be right. > > Really this must be kept as GFP_KERNEL allocations. > > Only if .call_rcu member is used in place of .call rcu_read_lock() is > held instead of nfnl_lock(). I thought we couldn't sleep while holding rcu_read_lock. > You should take a look at all GFP_ATOMIC uses in > net/netfilter/nf_conntrack_netlink.c and check if they can be GFP_KERNEL > instead. David, can you take all patches except this one? I'll have to rebase my tree after this, sorry.