[Linux-ia64] Re: alignment issues on netif_rx (fwd)

[Linux-ia64] Re: alignment issues on netif_rx (fwd)

[Keith Owens]

This just came up on the netdev list.  Is Andi correct and misaligned
IP options will cause a kernel error?

------- Forwarded Message

Return-Path: <owner-netdev@oss.sgi.com>
Date:   Sun, 17 Dec 2000 22:36:12 +0100
From:   Andi Kleen <ak@muc.de>
To:     Johannes Erdfelt <johannes@erdfelt.com>
Cc:     "David S. Miller" <davem@redhat.com>, kai@thphy.uni-duesseldorf.de,
        netdev@oss.sgi.com
Subject: Re: alignment issues on netif_rx

On Sun, Dec 17, 2000 at 04:21:14PM +0100, Johannes Erdfelt wrote:
> 
> However, I can't imagine we've made it this long without this being a
> problem so there must be something I'm missing.

Nobody apparently tried to use IPX on IA64 yet (due to a different ethernet
header length it usually has to deal with an misaligned header)

With this there are also plenty of ways to crash an IA64 box remotely,
e.g. by putting misaligned timestamps into options. 


- -Andi


------- End of Forwarded Message

Re: [Linux-ia64] Re: alignment issues on netif_rx (fwd)

[David Mosberger]

Yes, that's a known problem.  Unalignment fault handling is REALLY
slow on IA-64 so it's not something you want to do in general.
However, the kernel certainly shouldn't crash due to an unaligned
network header either, so we need to enable unaligned handling in the
kernel (along with printing a nasty message ;-).

	--david

>>>>> On Mon, 18 Dec 2000 11:42:14 +1100, Keith Owens <kaos@ocs.com.au> said:

  Keith> This just came up on the netdev list.  Is Andi correct and
  Keith> misaligned IP options will cause a kernel error?

  Keith> ------- Forwarded Message

  Keith> Return-Path: <owner-netdev@oss.sgi.com> Date: Sun, 17 Dec
  Keith> 2000 22:36:12 +0100 From: Andi Kleen <ak@muc.de> To: Johannes
  Keith> Erdfelt <johannes@erdfelt.com> Cc: "David S. Miller"
  Keith> <davem@redhat.com>, kai@thphy.uni-duesseldorf.de,
  Keith> netdev@oss.sgi.com Subject: Re: alignment issues on netif_rx

  Keith> On Sun, Dec 17, 2000 at 04:21:14PM +0100, Johannes Erdfelt
  Keith> wrote:
  >>  However, I can't imagine we've made it this long without this
  >> being a problem so there must be something I'm missing.

  Keith> Nobody apparently tried to use IPX on IA64 yet (due to a
  Keith> different ethernet header length it usually has to deal with
  Keith> an misaligned header)

  Keith> With this there are also plenty of ways to crash an IA64 box
  Keith> remotely, e.g. by putting misaligned timestamps into options.


  Keith> - -Andi


  Keith> ------- End of Forwarded Message



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