From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: alignment faults in 3.6
Date: Thu, 11 Oct 2012 12:00:38 +0200
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Cc: David Laight <David.Laight@ACULAB.COM>,
	Jon Masters <jonathan@jonmasters.org>,
	linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org
To: =?ISO-8859-1?Q?M=E5ns_Rullg=E5rd?= <mans@mansr.com>
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On Thu, 2012-10-11 at 10:45 +0100, M=C3=A5ns Rullg=C3=A5rd wrote:
> "David Laight" <David.Laight@ACULAB.COM> writes:
>=20
> >> -----Original Message-----
> >> From: netdev-owner@vger.kernel.org [mailto:netdev-owner@vger.kerne=
l.org] On Behalf Of M=C3=A5ns Rullg=C3=A5rd
> >> Sent: 11 October 2012 03:27
> >> To: Jon Masters
> >> Cc: linux-arm-kernel@lists.infradead.org; netdev@vger.kernel.org
> >> Subject: Re: alignment faults in 3.6
> >>=20
> >> Jon Masters <jonathan@jonmasters.org> writes:
> >>=20
> >> > Hi everyone,
> >> >
> >> > On 10/05/2012 10:33 AM, Rob Herring wrote:
> >> >> On 10/05/2012 09:05 AM, Russell King - ARM Linux wrote:
> >> >>> On Fri, Oct 05, 2012 at 07:24:44AM -0500, Rob Herring wrote:
> >> >>>> On 10/05/2012 03:24 AM, Russell King - ARM Linux wrote:
> >> >>>>> Does it matter?  I'm just relaying the argument against addi=
ng __packed
> >> >>>>> which was used before we were forced (by the networking folk=
) to implement
> >> >>>>> the alignment fault handler.
> >> >>>>
> >> >>>> It doesn't really matter what will be accepted or not as addi=
ng __packed
> >> >>>> to struct iphdr doesn't fix the problem anyway.=20
> > ...
> >> There are exactly two possible solutions:
> >>=20
> >> 1. Change the networking code so those structs are always aligned.=
  This
> >>    might not be (easily) possible.
> >> 2. Mark the structs __packed and fix any typecasts like the ones s=
een in
> >>    this thread.  This will have an adverse effect in cases where t=
he
> >>    structs are in fact aligned.
> >>=20
> >> Both solutions lie squarely in the networking code.  It's time to
> >> involve that list, or we'll never get anywhere.
> >
> > It might be enough to use __attribute__((aligned(2))) on some struc=
ture
> > members (actually does 'ldm' need 8 byte alignment?? - in which cas=
e
> > aligned(4) is enough).
>=20
> The aligned attribute can only increase alignment.
>=20

I have no idea what is the problem,=20

-ENOTENOUGHCONTEXT