gnome-shell crashed with SIGSEGV in st_widget_style_changed() from st_scroll_view_style_changed()

StacktraceTop:
 st_widget_style_changed (widget=0x0) at ../src/st/st-widget.c:544
 st_scroll_view_style_changed (widget=0x55d335a1dae0) at ../src/st/st-scroll-view.c:737
 _g_closure_invoke_va (closure=0x55d32eb1c590, return_value=0x0, instance=0x55d335a1dae0, args=0x7fff93fa3590, n_params=0, param_types=0x0) at ../../../../gobject/gclosure.c:867
 g_signal_emit_valist (instance=0x55d335a1dae0, signal_id=<optimized out>, detail=<optimized out>, var_args=var_args@entry=0x7fff93fa3590) at ../../../../gobject/gsignal.c:3300
 g_signal_emit (instance=instance@entry=0x55d335a1dae0, signal_id=<optimized out>, detail=detail@entry=0) at ../../../../gobject/gsignal.c:3447

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

Also tracking in:
https://errors.ubuntu.com/problem/f74709b604cdae437acbd6591fe8933bc3d8750a

We don't seem to have any upstream bug link here, but we also haven't seen any reports of this crash in 3.27. Looking good so far.

the e.u.c summary has some 3.28 reports

Yeah, I can look at it.

Preventing the crash is easy, the root cause a bit more complex. I can look at it, but I'd need some way to reproduce.

Bump. This is the single most common gnome-shell crash this month.

This bug was fixed in the package gnome-shell - 3.29.90-2ubuntu1

---------------
gnome-shell (3.29.90-2ubuntu1) cosmic; urgency=medium

  * Merge with debian, remaining changes
    + Replace gnome-backgrounds dep with ubuntu-wallpapers and Suggests
      gnome-themes-standard-data, gnome-backgrounds
    + Add some Recommends:
      - ubuntu-session (| gnome-session) to have the ubuntu session available
      - xserver-xorg-legacy
    + Update debian/gbp.conf with Ubuntu settings
    + gnome-shell-common.install: Install Ubuntu mode
    + gnome-shell-common.prerm: Remove deprecated ubuntu theme alternative
    + 50_add_ubuntu_desktop_detect.patch
      - add caching for desktop detection to avoid querying the current
        desktop env variable as iterate through the list each time. For the
        time of the Shell process, we can expect this env variable to stay
        stable.
    + 71_smarter_alt_tab.patch
      - quick alt-tab (without showing up the switcher) switch only between
        the last window of the last 2 applications to be focused instead of
        raising all windows of those apps.
    + optional-hot-corner.patch
      - enable patch proposed by upstream developer already in package (but
        not in series) to add a settings for optional hot corner activation.
    + ubuntu-lightdm-user-switching.patch
      - Allow user switching when using LightDM.
    + ubuntu_lock_on_suspend.patch
      - Respect Ubuntu's lock-on-suspend setting.
    + ubuntu_gdm.patch
      - as gdm is system-wide and not session-wide, ensure gdm has an ubuntu
        styling by default, not impacting the gnome user session though.
    + ubuntu_background_login.patch
      - Change default background color as we modified the default GDM color
        for our ubuntu session. Change it as well here, still applying the
        background noise loading.
    + ubuntu_gdm_alternatives.patch
      - Add support for GDM3 theme alternatives
    + ubuntu_block_mode_extension_update.patch
      - Don't allow ubuntu mode extension to update
    + volume-Add-back-sound-feedback-on-scroll.patch
      - Fix regression causing missing feedback on volume slider scroll
    + st-texture-cache-Cancel-sliced-image-loading-on-target-ac.patch
      - Fix possible crash on cache loading
    + js-ui-Choose-some-actors-to-cache-on-the-GPU.patch
      - Improve rendering of shell elements moving rendering to GPU
    + debian/rules:
      - Run dh_translations and work around an issue with Rosetta and plural
        translations
      - Run dh_install with fail-missing
  * d/p/ubuntu_background_login.patch,
    d/p/ubuntu_block_mode_extension_update.patch,
    d/p/50_add_ubuntu_desktop_detect.patch,
    d/p/ubuntu_gdm.patch,
    d/p/ubuntu_gdm_alternatives.patch,
    d/p/ubuntu-lightdm-user-switching.patch,
    d/p/ubuntu_lock_on_suspend.patch,
    d/p/71_smarter_alt_tab.patch:
    - Using Gbp-Pq Topic to ubuntu (so they get moved to debian/patches/ubuntu)
  * d/p/main-show-a-critical-message-on-gnome-shell-crash.patch,
    d/p/global-make-possible-to-set-debug-flags-dynamically.patch,
    d/p/main-increase-the-granularity-of-backtraces-in-SHELL_DEBU.patch,
    d/p/main-add-b...

Hello Jack, or anyone else affected,

Accepted gnome-shell into bionic-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/gnome-shell/3.28.3-0ubuntu0.18.04.3 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-bionic to verification-done-bionic. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-bionic. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

No reports are shown for the SRU version in

https://errors.ubuntu.com/problem/f74709b604cdae437acbd6591fe8933bc3d8750a

Nor for the cosmic version where we provided the same fix, so I think we can mark this as verified.

This bug was fixed in the package gnome-shell - 3.28.3-0ubuntu0.18.04.3

---------------
gnome-shell (3.28.3-0ubuntu0.18.04.3) bionic; urgency=medium

  * debian/ubuntu.css:
    - use defined color for menu separators (LP: #1739931)
    - set StEntry minimun height to work properly with Ubuntu font (LP: #1743058)
  * debian/patches/st-button-Ignore-pointer-emulated-touch-events.patch:
    - Don't emit two click events on touch under X11 (LP: #1745888)
  * d/p/st-scroll-view-Handle-the-case-where-scrollbars-are-NULL.patch,
    d/p/st-scroll-view-Remove-scrollbars-references-on-dispose.patch:
    - Handle NULL scroll bars in st-scroll-view (LP: #1725312)

 -- Marco Trevisan (Treviño) <email address hidden> Tue, 06 Nov 2018 17:49:17 +0000

The verification of the Stable Release Update for gnome-shell has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.