From: Florian Westphal <fw@strlen.de>
To: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
David Miller <davem@davemloft.net>,
Pablo Neira Ayuso <pablo@netfilter.org>,
Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>,
coreteam@netfilter.org, Florian Westphal <fw@strlen.de>
Subject: Re: [PATCH] netfilter: Force fake conntrack entry to be at least 8 bytes aligned
Date: Sat, 11 Mar 2017 10:12:22 +0100 [thread overview]
Message-ID: <20170311091222.GA24201@breakpoint.cc> (raw)
In-Reply-To: <20170311002526.1d21e750@gandalf.local.home>
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>
next prev parent reply other threads:[~2017-03-11 9:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-11 5:25 [PATCH] netfilter: Force fake conntrack entry to be at least 8 bytes aligned Steven Rostedt (VMware)
2017-03-11 9:12 ` Florian Westphal [this message]
2017-03-13 12:33 ` Pablo Neira Ayuso
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