Same problem (assumed) here with Kubuntu 16.04, and Kubuntu 17.10.
Nvidia 384.90 video drivers. 

Seeking in large files causes VLC to hang freezing the desktop session.

Sometimes I can CTL-ALT-F2 and get a console session.  VLC cant be killed, wont even die with a -9 for several minutes.

Sometimes I cant even CTL-ALT-F2 to a console. Graphical console is completely frozen.

I can ssh in, which leads me to believe that the problem is not that the entire system is frozen, just something in the video side.

Ive tried every setting in VLC I can from disabling hardware acceleration, use/dont use VDPAU, etc..

Other video players which do use HW Acceleration seem to have no issue.  The larger the file, the more I seek/skip, the more likley VLC is to trigger the freeze.

Relevant Graphical PKGS:
rc  libcg:amd64                                     3.1.0013-2                                       amd64        Nvidia Cg core runtime library
rc  libcggl:amd64                                   3.1.0013-2                                       amd64        Nvidia Cg Opengl runtime library
   all          X Window System (X.Org) infrastructure
ii  xfonts-utils                                    1:7.7+4                                          amd64        X Window System font utility programs
ii  xorg                                            1:7.7+19ubuntu3                                  amd64        X.Org X Window System
ii  libvdpau1:amd64                                 1.1.1-3ubuntu1                                   amd64        Video Decode and Presentation API for Unix (libraries)
ii  libvdpau1:i386                                  1.1.1-3ubuntu1                                   i386         Video Decode and Presentation API for Unix (libraries)
ii  mesa-vdpau-drivers:amd64                        17.2.2-0ubuntu1                                  amd64        Mesa VDPAU video acceleration drivers
ii  mesa-vdpau-drivers:i386                         17.2.2-0ubuntu1                                  i386         Mesa VDPAU video acceleration drivers
ii  vdpau-driver-all:amd64                          1.1.1-3ubuntu1                                   amd64        Video Decode and Presentation API for Unix (driver metapackage)
ii  vdpau-driver-all:i386                           1.1.1-3ubuntu1                                   i386         Video Decode and Presentation API for Unix (driver metapackage)
ii  vdpau-va-driver:amd64                           0.7.4-6                                          amd64        VDPAU-based backend for VA API
ii  vdpau-va-driver:i386                            0.7.4-6                                          i386         VDPAU-based backend for VA API
ii  vdpauinfo                                       1.0-1                                            amd64        Video Decode and Presentation API for Unix (vdpauinfo utility)
ii  libvlc-bin:amd64                                2.2.6-6                                          amd64        tools for VLC's base library
ii  libvlc5:amd64                                   2.2.6-6                                          amd64        multimedia player and streamer library
rc  libvlccore5                                     2.0.8-1                                          amd64        base library for VLC and its modules
rc  libvlccore7                                     2.1.6-0ubuntu14.04.1                             amd64        base library for VLC and its modules
ii  libvlccore8:amd64                               2.2.6-6                                          amd64        base library for VLC and its modules
ii  vlc                                             2.2.6-6                                          amd64        multimedia player and streamer
ii  vlc-bin                                         2.2.6-6                                          amd64        binaries from VLC
ii  vlc-data                                        2.2.6-6                                          all          Common data for VLC
ii  vlc-l10n                                        2.2.6-6                                          all          Translations for VLC
rc  vlc-nox                                         3.0.0~~git20160813+r65787+62~ubuntu16.04.1       amd64        multimedia player and streamer (without X support)
ii  vlc-plugin-base:amd64                           2.2.6-6                                          amd64        multimedia player and streamer (base plugins)
ii  vlc-plugin-notify:amd64                         2.2.6-6                                          amd64        LibNotify plugin for VLC
ii  vlc-plugin-qt:amd64                             2.2.6-6                                          amd64        multimedia player and streamer (Qt plugin)
ii  vlc-plugin-samba:amd64                          2.2.6-6                                          amd64        Samba plugin for VLC
ii  vlc-plugin-skins2:amd64                         2.2.6-6                                          amd64        multimedia player and streamer (Skins2 plugin)
ii  vlc-plugin-video-output:amd64                   2.2.6-6                                          amd64        multimedia player and streamer (video output plugins)
ii  vlc-plugin-video-splitter:amd64                 2.2.6-6                                          amd64        multimedia player and streamer (video splitter plugins)
ii  vlc-plugin-visualization:amd64                  2.2.6-6                                          amd64        multimedia player and streamer (visualization plugins)