Bug#572201: forcedeth driver hangs under heavy load

[stephen mulcahy <smulcahy@gmail.com>]

Eric Dumazet wrote:
> Le mardi 13 avril 2010 à 15:27 +0100, stephen mulcahy a écrit :
> > Ok, I've tried both of the following with my reproducer
> >
> > 1. ethtool -K eth0 tso off
> >
> > RESULT: reproducer causes multiple hosts to be come unresponsive on 
> > first run.
> >
> > 2. ethtool -K eth0 tx off
> >
> > RESULT: reproducer runs three times without any hosts becoming unresponsive.
> >
> > -stephen
>
> Thanks Stephen !
>
> Now some brave fouls to check the 6410 lines of this driver ? ;)
>
> Question of the day : Why TSO is broken in forcedeth ?
> Is it generically broken or is it broken for specific NICS ?

Actually, it is only when tx-checksumming is turned off that the problem 
 doesn't occur (so I'm not sure TSO is the problem).

Additionally, a google also turns up this existing Debian bug 
http://bugs.debian.org/506419 which seems to be related.

-stephen