[libvirt] [PATCH 4/5] rpc: avoid crashing in pre-exec if no workers are present

Daniel P. Berrangé berrange at redhat.com
Thu Mar 8 10:07:54 UTC 2018


On Wed, Mar 07, 2018 at 06:50:09PM -0500, John Ferlan wrote:
> 
> 
> On 03/06/2018 12:58 PM, Daniel P. Berrangé wrote:
> > If max_workers is set to zero, then the worker thread pool won't be
> > created, so when serializing state for pre-exec we must set various
> > parameters to zero.
> > 
> > Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
> > ---
> >  src/rpc/virnetserver.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> 
> Alternatively, the various virThreadPoolGet* API's could check :
> 
>     if (!pool)
>         return 0;
> 
> and we don't run into the same problem for other callers for all the API's.

My general opinion is that code should never knowingly pass NULL into
object methods, so I prefer to handle this in callers.

> 
> This works, but for this limited case of data being fetched.
> 
> It'd be a weak R-b at best.
> 
> John
> 
> > diff --git a/src/rpc/virnetserver.c b/src/rpc/virnetserver.c
> > index 7a1376bf49..3ce21a8f53 100644
> > --- a/src/rpc/virnetserver.c
> > +++ b/src/rpc/virnetserver.c
> > @@ -580,18 +580,21 @@ virJSONValuePtr virNetServerPreExecRestart(virNetServerPtr srv)
> >          goto error;
> >  
> >      if (virJSONValueObjectAppendNumberUint(object, "min_workers",
> > +                                           srv->workers == NULL ? 0 :
> >                                             virThreadPoolGetMinWorkers(srv->workers)) < 0) {
> >          virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> >                         _("Cannot set min_workers data in JSON document"));
> >          goto error;
> >      }
> >      if (virJSONValueObjectAppendNumberUint(object, "max_workers",
> > +                                           srv->workers == NULL ? 0 :
> >                                             virThreadPoolGetMaxWorkers(srv->workers)) < 0) {
> >          virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> >                         _("Cannot set max_workers data in JSON document"));
> >          goto error;
> >      }
> >      if (virJSONValueObjectAppendNumberUint(object, "priority_workers",
> > +                                           srv->workers == NULL ? 0 :
> >                                             virThreadPoolGetPriorityWorkers(srv->workers)) < 0) {
> >          virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> >                         _("Cannot set priority_workers data in JSON document"));
> > 

Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|




More information about the libvir-list mailing list