From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Florian Westphal <fw@strlen.de>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>,
LKML <linux-kernel@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
David Miller <davem@davemloft.net>,
Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>,
coreteam@netfilter.org, netfilter-devel@vger.kernel.org
Subject: Re: [PATCH] netfilter: Force fake conntrack entry to be at least 8 bytes aligned
Date: Mon, 13 Mar 2017 13:33:32 +0100 [thread overview]
Message-ID: <20170313123332.GA6790@salvia> (raw)
In-Reply-To: <20170311091222.GA24201@breakpoint.cc>
On Sat, Mar 11, 2017 at 10:12:22AM +0100, Florian Westphal wrote:
> Steven Rostedt (VMware) <rostedt@goodmis.org> wrote:
> > Since the nfct and nfctinfo have been combined, the nf_conn structure
> > must be at least 8 bytes aligned, as the 3 LSB bits are used for the
> > nfctinfo. But there's a fake nf_conn structure to denote untracked
> > connections, which is created by a PER_CPU construct. This does not
> > guarantee that it will be 8 bytes aligned and can break the logic in
> > determining the correct nfctinfo.
> >
> > I triggered this on a 32bit machine with the following error:
> [..]
>
> Ugh. Originally I had planned to also submit followup changes
> to get rid of the untracked objects but that part got delayed.
>
> > By using DEFINE/DECLARE_PER_CPU_ALIGNED we can enforce at least 8 byte
> > alignment as all cache line sizes are at least 8 bytes or more.
>
> Thanks for fixing this!
>
> Acked-by: Florian Westphal <fw@strlen.de>
Applied, thanks.
next parent reply other threads:[~2017-03-13 12:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20170311002526.1d21e750@gandalf.local.home>
[not found] ` <20170311091222.GA24201@breakpoint.cc>
2017-03-13 12:33 ` Pablo Neira Ayuso [this message]
2017-03-13 12:36 ` [PATCH] netfilter: Force fake conntrack entry to be at least 8 bytes aligned Pablo Neira Ayuso
2017-03-13 12:41 ` Florian Westphal
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