From: Sowmini Varadhan <sowmini.varadhan@oracle.com>
To: Tom Herbert <tom@herbertland.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
Michael Dalton <mwdalton@google.com>,
Linux Kernel Network Developers <netdev@vger.kernel.org>
Subject: Re: [RFC] Kernel unaligned access at __skb_flow_dissect
Date: Fri, 29 Jan 2016 18:04:24 -0500 [thread overview]
Message-ID: <20160129230424.GG17127@oracle.com> (raw)
In-Reply-To: <CALx6S35V47scFFQab7ZsQyh6CktS17w4hSKZSVAnOB0Ppa7brg@mail.gmail.com>
On (01/29/16 15:00), Tom Herbert wrote:
> The sparc documentation is pretty clear
> http://docs.oracle.com/cd/E19253-01/816-4854/hwovr-2/index.html, seems
> like unaligned accesses are not allowed in the architecture.
yes, but looks like you can paper over some of this with
memcpy (as was happening with the saddr ref in skb_flow_dissect
that puzzled me and Eric because it did not generate any traps).
I suppose one could sprinkele a few WARN_ON's for !IS_ALIGNED
but that's not a fool-proof detection method either (in addition
to all the ugly shouting in the code).
--Sowmini
next prev parent reply other threads:[~2016-01-29 23:04 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-29 18:06 [RFC] Kernel unaligned access at __skb_flow_dissect Sowmini Varadhan
2016-01-29 18:33 ` Eric Dumazet
2016-01-29 18:40 ` Eric Dumazet
2016-01-29 19:08 ` David Miller
2016-01-29 19:39 ` Eric Dumazet
2016-01-29 18:54 ` Eric Dumazet
2016-01-29 19:22 ` Sowmini Varadhan
2016-01-29 21:00 ` Tom Herbert
2016-01-29 21:09 ` Sowmini Varadhan
2016-01-29 21:33 ` Tom Herbert
2016-01-29 23:00 ` Tom Herbert
2016-01-29 23:04 ` Sowmini Varadhan [this message]
2016-01-29 23:31 ` Tom Herbert
2016-01-29 23:58 ` Sowmini Varadhan
2016-01-30 0:47 ` Tom Herbert
2016-01-30 1:18 ` David Miller
2016-01-30 2:15 ` Eric Dumazet
2016-01-31 22:13 ` Tom Herbert
2016-02-01 0:04 ` Eric Dumazet
2016-01-29 19:06 ` David Miller
2016-01-29 19:37 ` Eric Dumazet
2016-01-29 19:41 ` David Miller
2016-01-29 19:44 ` Sowmini Varadhan
2016-01-29 20:01 ` Eric Dumazet
2016-01-29 20:06 ` Eric Dumazet
2016-01-29 21:16 ` Alexander Duyck
2016-01-29 21:33 ` Eric Dumazet
2016-01-29 22:08 ` Alexander Duyck
2016-01-29 22:28 ` Eric Dumazet
2016-01-29 23:00 ` Alexander Duyck
2016-02-01 16:55 ` David Laight
2016-02-01 17:25 ` Eric Dumazet
2016-01-29 19:04 ` David Miller
2016-01-30 2:49 ` [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen Alexander Duyck
2016-01-30 3:23 ` Eric Dumazet
2016-01-30 3:35 ` David Miller
2016-01-30 4:46 ` Alexander Duyck
2016-01-30 16:17 ` Sowmini Varadhan
2016-01-30 17:43 ` Tom Herbert
2016-01-30 19:12 ` Sowmini Varadhan
2016-01-30 18:36 ` Alexander Duyck
2016-01-30 19:26 ` Eric Dumazet
2016-01-31 1:13 ` Alexander Duyck
2016-01-31 3:45 ` David Miller
2016-01-31 9:12 ` Alexander Duyck
2016-01-31 19:17 ` David Miller
2016-01-31 21:23 ` Sowmini Varadhan
2016-02-01 16:50 ` David Laight
2016-02-01 18:18 ` Alexander Duyck
2016-02-02 9:47 ` David Laight
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