Re: [Xen-devel] [PATCH 17/19] libxl: suspend: Fix suspend wait corner cases

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Thu, 2014-03-13 at 18:33 +0000, Ian Jackson wrote:
> Ian Campbell writes ("Re: [PATCH 17/19] libxl: suspend: Fix suspend wait 
> corner cases"):
> > On Tue, 2014-03-04 at 14:56 +0000, Ian Jackson wrote:
> > > +    if (ret < 0) {
> > > +        LOGE(ERROR, "unable to check for status of guest %"PRId32"", 
> > > domid);
> > > +        goto err;
> > > +        domain_suspend_common_failed(egc, dss);
> > 
> > You don't want this here.
> 
> Indeed I don't.
> 
> > > +    if (!(ret == 1 && info.domain == domid)) {
> > > +        LOGE(ERROR, "guest %"PRId32" we were suspending has been 
> > > destroyed",
> > > +             domid);
> > 
> > Is there an (unlikely) race here where a new domain gets created with
> > the same domid? Not that I have any suggestion what to do about that...
> 
> If domids are reused within the lifetime of the libxc/libxl code
> managing the domain, the whole edifice is unsafe.  AFAICT this is a
> fundamental problem which cannot be avoided in any toolstack
> which is capable of concurrently issuing hypercalls (specifically,
> destroying domains).

Yes. Oh well.

With the unwanted dmain_suspend call removed:

Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

Ian.



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel