On Wed, Nov 30, 2011 at 02:03:18PM +0100, Christophe Fergeau wrote:
> On Tue, Nov 29, 2011 at 11:51:38PM +0100, Christophe Fergeau wrote:
> > On Tue, Nov 29, 2011 at 05:00:54PM +0200, Zeeshan Ali (Khattak) wrote:
> > > From: "Zeeshan Ali (Khattak)" <zeeshanak@xxxxxxxxx>
> > >
> > > This patch doesn't work cause virDomainIsPersistent() is returning '1'
> > > on transient domain for some reason. Send it to list to get some help.
> > > ---
> > > libvirt-gobject/libvirt-gobject-connection.c | 9 +++++++++
> > > 1 files changed, 9 insertions(+), 0 deletions(-)
> > >
> > > diff --git a/libvirt-gobject/libvirt-gobject-connection.c b/libvirt-gobject/libvirt-gobject-connection.c
> > > index b647bfa..1b0259e 100644
> > > --- a/libvirt-gobject/libvirt-gobject-connection.c
> > > +++ b/libvirt-gobject/libvirt-gobject-connection.c
> > > @@ -362,6 +362,15 @@ static int domain_event_cb(virConnectPtr conn G_GNUC_UNUSED,
> > > g_signal_emit_by_name(gdom, "stopped::from-snapshot");
> > > else
> > > g_warn_if_reached();
> > > +
> > > + if (!virDomainIsPersistent(dom)) {
> > > + g_mutex_lock(priv->lock);
> > > + g_hash_table_steal(priv->domains, uuid);
> > > + g_mutex_unlock(priv->lock);
> > > +
> > > + g_signal_emit(gconn, signals[VIR_DOMAIN_REMOVED], 0, gdom);
> > > + g_object_unref(gdom);
> > > + }
> > > break;
> >
> > Not directly related to this patch since the same pattern is already
> > present in domain_event_cb, but this can race with gvir_connection_close,
> > ie gdom is looked up in domain_event_cb, gvir_connection_close frees
> > priv->domains and its content, domain_event_cb resumes and happily uses
> > gdom which it hasn't reffed and priv->domains. Something similar can also
> > happen between domain_event_cb and gvir_connection_fetch_domains.
>
> What about something like the patch below? I'll make a proper patch and
> make sure it does not conflict with Zeeshan's patch if that looks like the
> way to go.
>
> Christophe
>
>
> diff --git a/libvirt-gobject/libvirt-gobject-connection.c b/libvirt-gobject/libvirt-gobject-connection.c
> index c9985b2..e00c5bf 100644
> --- a/libvirt-gobject/libvirt-gobject-connection.c
> +++ b/libvirt-gobject/libvirt-gobject-connection.c
> @@ -261,6 +261,7 @@ static int domain_event_cb(virConnectPtr conn G_GNUC_UNUSED,
> GVirDomain *gdom;
> GVirConnectionPrivate *priv = gconn->priv;
> gboolean was_unknown = FALSE;
> + GHashTable *doms;
>
> if (virDomainGetUUIDString(dom, uuid) < 0) {
> g_warning("Failed to get domain UUID on %p", dom);
> @@ -270,14 +271,17 @@ static int domain_event_cb(virConnectPtr conn G_GNUC_UNUSED,
> g_debug("%s: %s event:%d, detail:%d", G_STRFUNC, uuid, event, detail);
>
> g_mutex_lock(priv->lock);
> - gdom = g_hash_table_lookup(priv->domains, uuid);
> + doms = g_hash_table_ref(priv->domains);
> + gdom = g_hash_table_lookup(doms, uuid);
> + if (gdom != NULL)
> + g_object_ref(G_OBJECT(gdom));
> g_mutex_unlock(priv->lock);
>
> if (gdom == NULL) {
> gdom = GVIR_DOMAIN(g_object_new(GVIR_TYPE_DOMAIN, "handle", dom, NULL));
>
> g_mutex_lock(priv->lock);
> - g_hash_table_insert(priv->domains, (gpointer)gvir_domain_get_uuid(gdom), gdom);
> + g_hash_table_insert(doms, (gpointer)gvir_domain_get_uuid(gdom), gdom);
> g_mutex_unlock(priv->lock);
>
> was_unknown = TRUE;
> @@ -296,11 +300,10 @@ static int domain_event_cb(virConnectPtr conn G_GNUC_UNUSED,
> case VIR_DOMAIN_EVENT_UNDEFINED:
> if (detail == VIR_DOMAIN_EVENT_UNDEFINED_REMOVED) {
> g_mutex_lock(priv->lock);
> - g_hash_table_steal(priv->domains, uuid);
> + g_hash_table_remove(doms, uuid);
> g_mutex_unlock(priv->lock);
>
> g_signal_emit(gconn, signals[VIR_DOMAIN_REMOVED], 0, gdom);
> - g_object_unref(gdom);
> } else
> g_warn_if_reached();
> break;
> @@ -372,6 +375,8 @@ static int domain_event_cb(virConnectPtr conn G_GNUC_UNUSED,
> g_warn_if_reached();
> }
>
> + g_object_unref(G_OBJECT(gdom));
> + g_hash_table_unref(doms);
> return 0;
> }
Looks reasonable to me.
Daniel
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