[virt-tools-list] [virt-viewer] Fix virt-viewer --reconnect crash with SPICE VMs

Fabiano Fidêncio fabiano at fidencio.org
Mon Mar 30 16:05:28 UTC 2015


On Mon, Mar 30, 2015 at 3:08 PM, Christophe Fergeau <cfergeau at redhat.com> wrote:
> When using virt-viewer --reconnect, virt-viewer currently crashes when
> a SPICE VM is destroyed with "virsh destroy"
>
> What happens is that when the guest is destroyed, virt-viewer receives a
> SPICE_CHANNEL_ERROR_IO notification in
> virt_viewer_session_spice_main_channel_event().  This triggers the
> emission of the "session-disconnected" signal, which will end up calling
> spice_session_disconnect() (indirectly through
> virt_viewer_app_disconnected/virt_viewer_app_deactivate).
>
> Since spice-gtk commit ff25f3e, the actual session disconnection is
> done from an idle.  When the "session-disconnected" emission stops, the
> VirtViewerSession instance is destroyed. However, the associated
> VirtViewerDisplaySpice are still alive as the various SpiceChannels
> instances hold a reference through the "virt-viewer-displays" GObject
> data.
> These channels are destroyed when the idle queued by spice_session_disconnect()
> run. The associated VirtViewerDisplay are in turn destroyed too, but
> this causes attempts to use the VirtViewerSession associated with the
> displays, which has already been destroyed. This causes a crash.
>
> This commit adds a virt_viewer_session_spice_clear_displays() which is
> similar to virt_viewer_session_clear_displays(), but makes sure the
> "virt-viewer-displays" references are dropped too. This ensures the
> VirtViewerDisplay instances don't outlive the VirtViewerSession
> they are associated with.
>
> Backtrace for the crash:
>
>  #0  0x0000000000413f0f in display_show_hint (display=0x85ab50 [VirtViewerDisplaySpice], pspec=0x939bd0 [GParamFlags], user_data=0x0) at virt-viewer-app.c:949
>  #4  0x00000031ff22a29f in <emit signal notify:show-hint on instance 0x85ab50 [VirtViewerDisplaySpice]> (instance=instance at entry=0x85ab50, signal_id=<optimized out>, detail=<optimized out>) at gsignal.c:3361
>      #1  0x00000031ff20fc45 in g_closure_invoke (closure=0xa98f50, return_value=return_value at entry=0x0, n_param_values=2, param_values=param_values at entry=0x7fffffffc700, invocation_hint=invocation_hint at entry=0x7fffffffc680) at gclosure.c:768
>      #2  0x00000031ff2214c9 in signal_emit_unlocked_R (node=node at entry=0x674f80, detail=detail at entry=1678, instance=instance at entry=0x85ab50, emission_return=emission_return at entry=0x0, instance_and_params=instance_and_params at entry=0x7fffffffc700) at gsignal.c:3549
>      #3  0x00000031ff229ed0 in g_signal_emit_valist (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>, var_args=var_args at entry=0x7fffffffc8d0) at gsignal.c:3305
>  #5  0x00000031ff214175 in g_object_dispatch_properties_changed (object=0x85ab50 [VirtViewerDisplaySpice], n_pspecs=<optimized out>, pspecs=<optimized out>) at gobject.c:1056
>  #6  0x00000031ff216661 in g_object_notify (pspec=0x939bd0 [GParamFlags], object=0x85ab50 [VirtViewerDisplaySpice]) at gobject.c:1149
>  #7  0x00000031ff216661 in g_object_notify (object=0x85ab50 [VirtViewerDisplaySpice], property_name=<optimized out>) at gobject.c:1197
>  #8  0x000000000041e5ab in virt_viewer_display_set_show_hint (self=0x85ab50 [VirtViewerDisplaySpice], mask=1, enable=0) at virt-viewer-display.c:691
>  #9  0x000000000042b62d in update_display_ready (self=0x85ab50 [VirtViewerDisplaySpice])
>      at virt-viewer-display-spice.c:145
>  #13 0x00000031ff22a29f in <emit signal notify:ready on instance 0x898590 [SpiceDisplay]> (instance=instance at entry=0x898590, signal_id=<optimized out>, detail=<optimized out>) at gsignal.c:3361
>      #10 0x00000031ff20fc45 in g_closure_invoke (closure=0x99b280, return_value=return_value at entry=0x0, n_param_values=2, param_values=param_values at entry=0x7fffffffcc50, invocation_hint=invocation_hint at entry=0x7fffffffcbd0) at gclosure.c:768
>      #11 0x00000031ff2214c9 in signal_emit_unlocked_R (node=node at entry=0x674f80, detail=detail at entry=1696, instance=instance at entry=0x898590, emission_return=emission_return at entry=0x0, instance_and_params=instance_and_params at entry=0x7fffffffcc50) at gsignal.c:3549
>      #12 0x00000031ff229ed0 in g_signal_emit_valist (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>, var_args=var_args at entry=0x7fffffffce20) at gsignal.c:3305
>  #14 0x00000031ff214175 in g_object_dispatch_properties_changed (object=0x898590 [SpiceDisplay], n_pspecs=<optimized out>, pspecs=<optimized out>) at gobject.c:1056
>  #15 0x00000031ff216661 in g_object_notify (pspec=0xa83370 [GParamBoolean], object=0x898590 [SpiceDisplay]) at gobject.c:1149
>  #16 0x00000031ff216661 in g_object_notify (object=0x898590 [SpiceDisplay], property_name=<optimized out>) at gobject.c:1197
>  #17 0x00007ffff7522525 in update_ready (display=0x898590 [SpiceDisplay]) at spice-widget.c:236
>  #18 0x00007ffff752257e in set_monitor_ready (self=0x898590 [SpiceDisplay], ready=0)
>      at spice-widget.c:244
>  #19 0x00007ffff75274e6 in primary_destroy (channel=0x89f5c0 [SpiceDisplayChannel], data=0x898590)
>      at spice-widget.c:2169
>  #20 0x00007ffff7528918 in channel_destroy (s=0x909fa0 [SpiceSession], channel=0x89f5c0 [SpiceDisplayChannel], data=0x898590) at spice-widget.c:2484
>  #24 0x00000031ff22a29f in <emit signal ??? on instance 0x909fa0 [SpiceSession]> (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>) at gsignal.c:3361
>      #21 0x00000031ff20fc45 in g_closure_invoke (closure=0xa9bda0, return_value=return_value at entry=0x0, n_param_values=2, param_values=param_values at entry=0x7fffffffd280, invocation_hint=invocation_hint at entry=0x7fffffffd200) at gclosure.c:768
>      #22 0x00000031ff2214c9 in signal_emit_unlocked_R (node=node at entry=0x9c17d0, detail=detail at entry=0, instance=instance at entry=0x909fa0, emission_return=emission_return at entry=0x0, instance_and_params=instance_and_params at entry=0x7fffffffd280) at gsignal.c:3549
>      #23 0x00000031ff229ed0 in g_signal_emit_valist (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>, var_args=var_args at entry=0x7fffffffd450) at gsignal.c:3305
>  #25 0x00007ffff71c3248 in spice_session_channel_destroy (session=0x909fa0 [SpiceSession], channel=0x89f5c0 [SpiceDisplayChannel]) at spice-session.c:2217
>  #26 0x00007ffff71bd8b2 in session_disconnect (self=0x909fa0 [SpiceSession], keep_main=0)
>      at spice-session.c:281
>  #27 0x00007ffff71c1b27 in session_disconnect_idle (self=0x909fa0 [SpiceSession]) at spice-session.c:1853
>  #28 0x00000031fee4a0ba in g_main_context_dispatch (context=0x6a4400) at gmain.c:3122
>  #29 0x00000031fee4a0ba in g_main_context_dispatch (context=context at entry=0x6a4400) at gmain.c:3737
>  #30 0x00000031fee4a450 in g_main_context_iterate (context=0x6a4400, block=block at entry=1, dispatch=dispatch at entry=1, self=<optimized out>) at gmain.c:3808
>  #31 0x00000031fee4a772 in g_main_loop_run (loop=0x9890f0) at gmain.c:4002
>  #32 0x0000003babc05f75 in gtk_main () at gtkmain.c:1219
>  #33 0x000000000043143b in main (argc=1, argv=0x7fffffffda48) at virt-viewer-main.c:12
> ---
>  src/virt-viewer-session-spice.c | 20 ++++++++++++++++++--
>  1 file changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/src/virt-viewer-session-spice.c b/src/virt-viewer-session-spice.c
> index 3398f13..4d504dd 100644
> --- a/src/virt-viewer-session-spice.c
> +++ b/src/virt-viewer-session-spice.c
> @@ -90,6 +90,22 @@ static void virt_viewer_session_spice_smartcard_remove(VirtViewerSession *sessio
>  static gboolean virt_viewer_session_spice_fullscreen_auto_conf(VirtViewerSessionSpice *self);
>  static void virt_viewer_session_spice_apply_monitor_geometry(VirtViewerSession *self, GdkRectangle *monitors, guint nmonitors);
>
> +static void virt_viewer_session_spice_clear_displays(VirtViewerSessionSpice *self)
> +{
> +    SpiceSession *session = self->priv->session;
> +    GList *l;
> +    GList *channels;
> +
> +    channels = spice_session_get_channels(session);
> +    for (l = channels; l != NULL; l = l->next) {
> +        SpiceChannel *channel = SPICE_CHANNEL(l->data);
> +
> +        g_object_set_data(G_OBJECT(channel), "virt-viewer-displays", NULL);
> +    }
> +    virt_viewer_session_clear_displays(VIRT_VIEWER_SESSION(self));
> +}
> +
> +
>  static void
>  virt_viewer_session_spice_get_property(GObject *object, guint property_id,
>                                         GValue *value, GParamSpec *pspec)
> @@ -303,7 +319,7 @@ virt_viewer_session_spice_close(VirtViewerSession *session)
>
>      g_object_add_weak_pointer(G_OBJECT(self), (gpointer*)&self);
>
> -    virt_viewer_session_clear_displays(session);
> +    virt_viewer_session_spice_clear_displays(self);
>
>      if (self->priv->session) {
>          spice_session_disconnect(self->priv->session);
> @@ -518,7 +534,7 @@ virt_viewer_session_spice_main_channel_event(SpiceChannel *channel G_GNUC_UNUSED
>      case SPICE_CHANNEL_CLOSED:
>          g_debug("main channel: closed");
>          /* Ensure the other channels get closed too */
> -        virt_viewer_session_clear_displays(session);
> +        virt_viewer_session_spice_clear_displays(self);
>          if (self->priv->session)
>              spice_session_disconnect(self->priv->session);
>          break;
> --
> 2.3.4
>
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ACK!

Best Regards,
-- 
Fabiano Fidêncio




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