gnome-shell crashed with SIGSEGV in cogl_object_unref() from iter_remove_or_steal() from g_hash_table_iter_remove() from st_texture_cache_evict_icons() from on_icon_theme_changed()

StacktraceTop:
 cogl_object_unref (obj=0x0) at cogl-object.c:112
 iter_remove_or_steal (ri=ri@entry=0x7ffda4fa7fc0, notify=notify@entry=1) at ../../../../glib/ghash.c:851
 g_hash_table_iter_remove (iter=iter@entry=0x7ffda4fa7fc0) at ../../../../glib/ghash.c:887
 st_texture_cache_evict_icons (cache=0x561a8fa69a60) at ../src/st/st-texture-cache.c:125
 on_icon_theme_changed (icon_theme=<optimized out>, cache=0x561a8fa69a60) at ../src/st/st-texture-cache.c:133

Dropped importance to Low, because the stack trace suggests this crash could only happen when changing the icon theme(?)

Status changed to 'Confirmed' because the bug affects multiple users.

Also tracking in:
https://errors.ubuntu.com/problem/990288ee13e03a048791700aa0af1ccfaecd49bc

And in:
https://errors.ubuntu.com/problem/e4d313a6d362e991dc79947946d24a22a3a2f84a

My bug #1763850 got marked as a dupplicate (and probably is). It's seems to only occur once after a fresh install on my system. I tried to reproduced and succeeded.
What I did was:
a fresh install with encrypted drive,
login to regular "ubuntu"-session,
update all software,
reboot,
login to "ubuntu wayland"-session -> image freezes -> thrown-back to login screen,
login to regular "ubuntu"-session,
do things for a few minutes (I was surfing with firefox both times) -> crash report appears on-screen.

I'm happy to assist in what capacity I can. Currently I'm not using the computer for anything else, so I can format the drive and reinstall ubuntu again, if some more details are required.

This bug was fixed in the package gnome-shell - 3.28.1-0ubuntu1

---------------
gnome-shell (3.28.1-0ubuntu1) bionic; urgency=medium

  [ Jeremy Bicha ]
  * New upstream release
  * Drop obsolete patches:
    - 27-nm-libexec-path.patch
    - fix-wayland-vbox-crash.patch

  [ Marco Trevisan (Treviño) ]
  Cherry-pick patches applied to upstream git master:
  * ui-Theme-lookup-should-respect-XDG_DATA_DIRS.patch:
    - Renamed from ubuntu_theme_lookup_xdg.patch and cherry-picked from
      upstream
  * workspaceThumbnail-only-update-_porthole-if-the-overview-.patch:
    workspaceThumbnail-rebuild-thumbnails-if-workareas-size-c.patch:
    workspaceThumbnail-initialize-porthole-based-on-workArea.patch:
    - Cherry-picks from upstream, avoid unneeded computations in activities
  * popupMenu-Fix-wrong-call-to-clutter_actor_add_child.patch:
    - Cherry-pick from upstream
  * volume-Add-back-sound-feedback-on-scroll.patch:
    - Fix regression causing missing feedback on volume slider scroll

  Add patches proposed upstream:
  * shell-ignore-invalid-window-monitor-index.patch:
    - Fix crash on accessing on invalid monitor windows (LP: #1724439)
  * StIcon-only-compute-shadow-pipeline-when-the-texture-is-p.patch:
    - Don't try to compute shadows on not allocated icons (LP: #1723378)
  * js-fix-invalid-access-errors.patch:
    - Fix javascript errors (LP: #1747566)
  * workspace-fix-repositioned-windows-in-activities.patch:
    - Ensure windows thumbnails coordinates are correct (LP: #1653153)
  * st-texture-cache-Cancel-sliced-image-loading-on-target-ac.patch:
    - Fix possible crash on cache loading
  * st-texture-cache-Don-t-add-NULL-textures-to-cache.patch:
    - Fix crash when deleting NULL textures from cache (LP: #1754445)

 -- Marco Trevisan (Treviño) <email address hidden> Tue, 17 Apr 2018 14:40:17 -0400

Upstream bug: https://gitlab.gnome.org/GNOME/gnome-shell/issues/210