sparc64/80410: netgraph is causing crash with mpd on sparc64

[Sten Spans]

On Wed, 27 Apr 2005, Sten Spans wrote:

> On Wed, 27 Apr 2005, Andrew Belashov wrote:
>
>> 
>>> Description:
>> 	mpd does not work on FreeBSD/sparc64. Kernel panic with "memory 
>> address
>> not aligned" trap message.
>> 
>>> How-To-Repeat:
>> 	Configure and run mpd for VPN over pptp. After connect to VPN,
>> start nmap scanner. Kernel right away crashed. I have coredump:
>> 
>
> Finding unaligned ( or rather not 64bit aligned ) mbufs is the
> new cool thing, try if_em or if_tap for more fun and games :).
>
> On a more serious note, the main problem is that l3 protocols
> ( ip, ipv6, ipx ) expect their data to be aligned a certain way.
>
> But newer ethernet cards, complex headers, complex tunneling
> tricks, etc often shift contents a few bytes. i386 has no alignment 
> constraints ( a small speed hit though ) which means that these
> problems are often overlooked.
>
> OpenBSD and NetBSD have quite a few dirty hacks in drivers to
> fixup the mess for each driver. Some work has been done with
> m_copyup in -CURRENT but the debate is still open on wether
> this should be fixed in a general way in l3 protocols, or in
> each "ethernet" driver, or even somewhere else entirely.
>
> HTH HAND


http://mail-index.netbsd.org/source-changes/2002/07/01/0001.html

After some more thought, this would indeed seem to be the
right direction. It would certainly make life for alpha
and sparc64 users a lot less painfull.

Lets hope it'll make 6.0-RELEASE

-- 
Sten Spans

"There is a crack in everything, that's how the light gets in."
Leonard Cohen - Anthem