lkml.org 
[lkml]   [2019]   [Jul]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] vhost: disable metadata prefetch optimization
On Fri, Jul 26, 2019 at 07:57:25PM +0800, Jason Wang wrote:
>
> On 2019/7/26 下午7:51, Michael S. Tsirkin wrote:
> > This seems to cause guest and host memory corruption.
> > Disable for now until we get a better handle on that.
> >
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >
> > I put this in linux-next, we'll re-enable if we can fix
> > the outstanding issues in a short order.
>
>
> Btw, is this more suitable to e.g revert the
> 842aa64eddacd23adc6ecdbc69cb2030bec47122

Yes I did that too.

> and let syzbot fuzz more on the
> current code?

Current metadata direct access code is known to corrupt guest and host
memory - I don't feel we need more fuzzing.

>
> I think we won't accept that patch eventually, so I suspect what syzbot
> reports today is a false positives.

Today's reports are real, it's a bug in my patch. But I reverted it -
the below is an easier way to make sure at least linux-next is stable
for everyone.

>
> Thanks
>
>
> >
> > drivers/vhost/vhost.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> > index 819296332913..42a8c2a13ab1 100644
> > --- a/drivers/vhost/vhost.h
> > +++ b/drivers/vhost/vhost.h
> > @@ -96,7 +96,7 @@ struct vhost_uaddr {
> > };
> > #if defined(CONFIG_MMU_NOTIFIER) && ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 0
> > -#define VHOST_ARCH_CAN_ACCEL_UACCESS 1
> > +#define VHOST_ARCH_CAN_ACCEL_UACCESS 0
> > #else
> > #define VHOST_ARCH_CAN_ACCEL_UACCESS 0
> > #endif

\
 
 \ /
  Last update: 2019-07-26 16:09    [W:0.045 / U:16.956 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site