Re: [libvirt] [libvirt-glib 2/2] Remove transient domain reference on shutdown

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(a)gnome.org&gt; > > > > 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; }