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Subject: Re: [PATCH 5/5] net: Block MSG_CMSG_COMPAT in send(m)msg and
 recv(m)msg
From: Eric Dumazet <eric.dumazet@gmail.com>
To: Michael Neuling <mikey@neuling.org>
Date: Wed, 05 Jun 2013 21:35:25 -0700
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Cc: netdev@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org,
 Andy Lutomirski <luto@amacapital.net>, Linux PPC dev <linuxppc-dev@ozlabs.org>,
 Anton Blanchard <anton@samba.org>, trinity@vger.kernel.org,
 torvalds@linux-foundation.org, "David S. Miller" <davem@davemloft.net>
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On Thu, 2013-06-06 at 12:56 +1000, Michael Neuling wrote:
> On Thu, May 23, 2013 at 7:07 AM, Andy Lutomirski <luto@amacapital.net> wrote:
> > MSG_CMSG_COMPAT is (AFAIK) not intended to be part of the API --
> > it's a hack that steals a bit to indicate to other networking code
> > that a compat entry was used.  So don't allow it from a non-compat
> > syscall.
> 
> Dave & Linus
> 
> This is causing a regression on 64bit powerpc with 32bit usermode.
> When I hit userspace, udev is broken and I suspect all networking is
> broken as well.
> 
> Can we please revert 1be374a0518a288147c6a7398792583200a67261 upstream?
> 

It seems to also break x86_64, if using 32bit usermode.