Subject: Re: HEAD instability on Xen
To: Andrew Doran <>
From: Manuel Bouyer <>
List: port-i386
Date: 11/18/2007 23:12:38
On Sun, Nov 18, 2007 at 10:08:03PM +0000, Andrew Doran wrote:
> Acutally, it already has all the necessary changes. Is there a point where
> the kernel is entered with Xen that the direction flag might not be cleared?

I'll have a look. Could it be a missing lock or splxx() in the pmap ?

> I can't see one. It is cleared for the copyout() in the traceback that you
> posted.
> > I've also seen it in the pool code. It was always handling a trap after a
> > copyin or copyout though.
> I did many hours of low-memory stress testing on the updated pool code
> before checking it in, so I don't believe that there is an (obvious) problem
> there. It could be perhaps be related to the removal of the _CPU options.

No, I've seen it with a kernel from before the _CPU options removal
(the bouyer-xenamd64-base2 tag in src/sys). 

Manuel Bouyer <>
     NetBSD: 26 ans d'experience feront toujours la difference