Surprisingly, this is a bug in the virtualbox-guest code (version 5.2.20), that is triggered only when compiling with kernel 4.19 : position of closing brace } is wrong at line 493. Here is a patch that makes it compile with the new kernel. I have not checked wether it actually works, but see no reason why it shouldn't. The patch below is to be applied to
/usr/src/virtualbox-guest-5.2.20/vboxvideo/vbox_mode.c
before retrying d-u (or better : patch the package source code and reinstall)
*** vbox_mode.c.orig 2018-11-02 11:06:35.457890211 +0100
--- vbox_mode.c 2018-11-02 10:56:04.977870035 +0100
***************
*** 490,498 ****
drm_connector_update_edid_property(connector, (struct edid *)edid);
#else
drm_mode_connector_update_edid_property(connector, (struct edid *)edid);
- }
#endif
!
static int vbox_get_modes(struct drm_connector *connector)
{
--- 490,497 ----
drm_connector_update_edid_property(connector, (struct edid *)edid);
#else
drm_mode_connector_update_edid_property(connector, (struct edid *)edid);
#endif
! }
static int vbox_get_modes(struct drm_connector *connector)
{