qxl: fix local renderer crash

Make sure we only ask the spice local renderer for display updates in
case we have a valid primary surface.  Without that spice is confused
and throws errors in case a display update request (triggered by
screendump for example) happens in parallel to a mode switch and hits
the race window where the old primary surface is gone and the new isn't
establisted yet.

Cc: qemu-stable@nongnu.org
Fixes: https://bugzilla.redhat.com//show_bug.cgi?id=1567733
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 20180427115528.345-1-kraxel@redhat.com
(cherry picked from commit 5bd5c27c7d284d01477c5cc022ce22438c46bf9f)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

diff --git a/hw/display/qxl-render.c b/hw/display/qxl-render.c
index e7ac4f8789604f5daf62f5cf474c841cf128a8ea..c62b9a5e7543f704209b1669af558dbff7438d91 100644 (file)
--- a/hw/display/qxl-render.c
+++ b/hw/display/qxl-render.c
@@ -169,7 +169,8 @@ void qxl_render_update(PCIQXLDevice *qxl)
 
     qemu_mutex_lock(&qxl->ssd.lock);
 
-    if (!runstate_is_running() || !qxl->guest_primary.commands) {
+    if (!runstate_is_running() || !qxl->guest_primary.commands ||
+        qxl->mode == QXL_MODE_UNDEFINED) {
         qxl_render_update_area_unlocked(qxl);
         qemu_mutex_unlock(&qxl->ssd.lock);
         return;