netdev - Re: nf_conntrack_h323: Fix locking in process

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Message-ID: <20160115224233.GA20767@breakpoint.cc>
Date:	Fri, 15 Jan 2016 23:42:33 +0100
From:	Florian Westphal <fw@...len.de>
To:	Sebastian Pöhn <sebastian.poehn@...il.com>
Cc:	netdev@...r.kernel.org, netfilter-devel@...r.kernel.org
Subject: Re: nf_conntrack_h323: Fix locking in process_urq

Sebastian Pöhn <sebastian.poehn@...il.com> wrote:

[ CC netfilter-devel ]

> nf_ct_remove_expectations has to be called under nf_conntrack_expect_lock

But nf_ct_remove_expectations grabs that lock?

Added in:

commit ca7433df3a672efc88e08222cfa4b3aa965ca324
Author: Jesper Dangaard Brouer <brouer@...hat.com>
netfilter: conntrack: seperate expect locking from nf_conntrack_lock

> diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c
> index 9511af0..d477375 100644
> --- a/net/netfilter/nf_conntrack_h323_main.c
> +++ b/net/netfilter/nf_conntrack_h323_main.c
> @@ -1518,7 +1518,9 @@ static int process_urq(struct sk_buff *skb, struct nf_conn *ct,
>         }
>  
>         /* Clear old expect */
> +       spin_lock_bh(&nf_conntrack_expect_lock);
>         nf_ct_remove_expectations(ct);

... so I'd expect deadlock.