Re: sendfile() broken with 2.6.26 + Apache 2 ?

[Eric Dumazet]

Ian Jeffray a écrit :
> Hi Eric,
>
> Thanks for directing me to a better list.
>
> Further responses below:
>
> Eric Dumazet wrote:
> > CC to netdev where this report might find better answers
> >
> > Ian Jeffray a écrit :
> > > All,
> > >
> > > I moved from kernel 2.6.25.4 to 2.6.26 yesterday and observed that
> > > large files sent via Apache2 are partially corrupt.
> > >
> > > This appears to be linked to sendfile() -- disabling the use of
> > > sendfile in the apache config (EnableSendfile Off) allows it to
> > > function as normal.
> > >
> > > My system is a simple Core2Duo running Debian lenny/sid; nothing
> > > special, and I have never observed problems like this before.
> > >
> > > The problem feels certainly related to sendfile() since the data
> > > reads correctly from disc in other programs, and via CIFS etc.
> > >
> > > The corruption happens part-way in to the file... I've no exact
> > > figure but it would seem like maybe 32KB -- I'm seeing broken
> > > PNGs served from Apache, where the top few dozen lines decode
> > > correctly, and the rest is garbage.
> > >
> > > I've made basically no configuration changes between 2.6.25.4 and
> > > 2.6.26 and have explicitly tried both enabling and disabling the
> > > new PAT support to no effect.
> > >
> > > This is completely repeatable and reproducible.
> > >
> > > Is anyone else seeing this broken behaviour?
> >
> >
> > What kind of network adapter are you using ? (lspci | grep -i ether)
>
> 02:00.0 Ethernet controller: Attansic Technology Corp. L1 Gigabit 
> Ethernet Adapter (rev b0)
>
>
> > If you disable TCP segmentation offload on this NIC (ethtool -K eth0 
> > tso off) , is this problem still present ?
>
> Wow.  That 'solves' the problem!  Great.
>
> Does this therefore point to an attansic driver issue?


Yes, maybe related to commit 9d90fb1ac9d97da86e24d9ea947bf2a2f333829a 

In this patch, Jay Cliburn enabled TSO by default for atl1 driver.

This might be a driver problem, or a generic sendfile() problem, I dont know...




--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/