Re: atl1 64-bit => 32-bit DMA borkage (reproducible, bisected)

Alexey Dobriyan
2008-04-20T19:59:54Z

On Sun, Apr 20, 2008 at 01:37:04PM -0500, Jay Cliburn wrote:
> On Sun, 20 Apr 2008 16:26:31 +0400
> Alexey Dobriyan <adobriyan@gmail.com> wrote:
>
> > On Sun, Apr 20, 2008 at 06:06:07AM -0500, Jay Cliburn wrote:
> > > On Sun, 20 Apr 2008 15:14:53 +0400
> > > Alexey Dobriyan <adobriyan@gmail.com> wrote:
> > >
> > > > On Sat, Apr 19, 2008 at 09:54:44PM -0500, Jay Cliburn wrote:
> > > > > On Sat, 19 Apr 2008 18:45:35 +0400
> > > > > Alexey Dobriyan <adobriyan@gmail.com> wrote:
> [...]
> > > > > > So, it's enough to scp 200 MB git archive and immediately
> > > > > > start rebooting sequence for horrors described above to
> > > > > > appear. It's not 100% reproducible but more like 90%.
> > > > >
> > > > > Do I understand correctly that these failures occur only while
> > > > > the network interface is going down?
> > > >
> > > > Yep. During up or running there were no problems with this card.
> > > >
> > >
> > > One more question: Does it happen whether or not you're using atl1
> > > as a netconsole?
> >
> > Without netconsole bugs happens too.
> >
>
> I can't duplicate this error, but it's probably because my machine
> doesn't have 4GB of memory.
>
> I have one report in Febroary 2008 of another user encountering strange
> oopses in 2.6.23.12 and 2.6.24 whenever he downed the interface. I
> suspect your experience is a repeat of that.
>
> Just to be clear, you transfer about 200MB to the NIC (Rx direction),
> then immediately reboot, right?

Yup!

> Can you duplicate the problem if you
> simply ifconfig down instead of rebooting after the transfer?

Aha, ifconfig down is enough. Here is how reproducer looks like now:

./sync-linux-linus && ssh core2 "sudo /sbin/ifconfig eth0 down"

where first script is basically scp(1).

Also, booting with 1G or 2G of RAM (mem=1024m) makes issue go away.

printk at dev_close() time shows that NETIF_F_HIGHDMA was not somehow
enabled.