gnome-shell crashed with SIGSEGV in get_top_visible_window_actor() from meta_compositor_sync_stack() from meta_stack_tracker_sync_stack() from stack_tracker_sync_stack_later() from call_later_func()

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

Looks like this might be related to an older crash (the stack trace has changed a little over some versions): https://gitlab.gnome.org/GNOME/mutter/issues/338

Probably fixed by upstream commit b002343dcaebe2f102f1f9ec037e7b0277de0ae2 in 3.36.4. At least the upstream bug is closed as such.

This bug was fixed in the package mutter - 3.36.4-1ubuntu1

---------------
mutter (3.36.4-1ubuntu1) groovy; urgency=medium

  * Merge with debian, including new upstream stable release, remaining changes:
    - debian/control:
      + Update VCS flags to point to ubuntu salsa branch
    - debian/gbp.conf: update branch to point to ubuntu/master
    - debian/patches/x11-Add-support-for-fractional-scaling-using-Randr.patch:
      + X11: Add support for fractional scaling using Randr
  * debian/patches/x11-Add-support-for-fractional-scaling-using-Randr.patch:
    - Don't export patch-only private symbol
  * debian/libmutter-6-0.symbols:
    - Remove ubuntu-only private symbol

mutter (3.36.4-1) unstable; urgency=medium

  * New upstream stable release (LP: #1887998)
    - Fix crash on area screenshots with fractional scaling
    - Do not paint textures of fully obscured windows
    - Turn off CRTCs as well when enabling DPMS
    - Improve selection support
    - Use a more appropriate combine function on opaque areas
    - Fix remote desktop being broken without screencast session
    - Fix popovers disappearing on wayland and HiDPI
    - Fixed crashes (LP: #1870867, LP: #1857947)
    - Plugged memory leaks
  * d/p/screen-cast-Let-the-reason-for-recording-determine-what-t.patch,
    d/p/screen-cast-src-Add-flag-to-maybe_record.patch,
    d/p/screen-cast-src-Fix-signedness-of-timestamp-field.patch,
    d/p/screen-cast-src-Make-record-functions-return-an-error-whe.patch,
    d/p/screen-cast-src-Make-the-two-record-vfuncs-more-similarly.patch,
    d/p/screen-cast-src-Record-follow-up-frame-after-timeout.patch,
    d/p/screen-cast-src-Remove-follow-up-timeout-source-on-disabl.patch,
    d/p/screen-cast-src-Use-G_USEC_PER_SEC-instead-of-1000000.patch,
    d/p/screen-cast-window-stream-src-Fix-indentation.patch:
    - Import more fixes for screencasting and remote desktop

 -- Marco Trevisan (Treviño) <email address hidden> Mon, 20 Jul 2020 15:45:20 +0200

Hello errors.ubuntu.com, or anyone else affected,

Accepted mutter into focal-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/mutter/3.36.4-0ubuntu0.20.04.1 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, what testing has been performed on the package and change the tag from verification-needed-focal to verification-done-focal. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-focal. 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.

Hello errors.ubuntu.com, or anyone else affected,

Accepted mutter into focal-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/mutter/3.36.4-0ubuntu0.20.04.2 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, what testing has been performed on the package and change the tag from verification-needed-focal to verification-done-focal. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-focal. 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.

This crash doesn't seem to reproduce anymore, and there's no trace of it in e.u.c since version 3.36.4 went in proposed.

❯ apt-cache policy libmutter-6-0
libmutter-6-0:
  Installed: 3.36.4-0ubuntu0.20.04.2
  Candidate: 3.36.4-0ubuntu0.20.04.2
  Version table:
 *** 3.36.4-0ubuntu0.20.04.2 500
        500 http://it.archive.ubuntu.com/ubuntu focal-proposed/main amd64 Packages
        100 /var/lib/dpkg/status
     3.36.3-0ubuntu0.20.04.1 500
        500 http://it.archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages
     3.36.1-3ubuntu3 500
        500 http://it.archive.ubuntu.com/ubuntu focal/main amd64 Packages

This bug was fixed in the package mutter - 3.36.4-0ubuntu0.20.04.2

---------------
mutter (3.36.4-0ubuntu0.20.04.2) focal; urgency=medium

  * xrandr-scaling: Never try to set invalid screen sizes (LP: #1889090)

mutter (3.36.4-0ubuntu0.20.04.1) focal; urgency=medium

  * New upstream stable release (LP: #1887998)
    - Fix crash on area screenshots with fractional scaling
    - Do not paint textures of fully obscured windows
    - Turn off CRTCs as well when enabling DPMS
    - Improve selection support
    - Use a more appropriate combine function on opaque areas
    - Fix remote desktop being broken without screencast session
    - Fix popovers disappearing on wayland and HiDPI
    - Fixed crashes (LP: #1870867, LP: #1857947)
    - Plugged memory leaks
  * d/p/screen-cast-Let-the-reason-for-recording-determine-what-t.patch,
    d/p/screen-cast-src-Add-flag-to-maybe_record.patch,
    d/p/screen-cast-src-Fix-signedness-of-timestamp-field.patch,
    d/p/screen-cast-src-Make-record-functions-return-an-error-whe.patch,
    d/p/screen-cast-src-Make-the-two-record-vfuncs-more-similarly.patch,
    d/p/screen-cast-src-Record-follow-up-frame-after-timeout.patch,
    d/p/screen-cast-src-Remove-follow-up-timeout-source-on-disabl.patch,
    d/p/screen-cast-src-Use-G_USEC_PER_SEC-instead-of-1000000.patch,
    d/p/screen-cast-window-stream-src-Fix-indentation.patch:
    - Import more fixes for screencasting and remote desktop
  * d/p/x11-Add-support-for-fractional-scaling-using-Randr.patch:
    - Don't export patch-only private symbol
  * debian/libmutter-6-0.symbols:
    - Remove ubuntu-only private symbol

mutter (3.36.3-0ubuntu0.20.04.2) focal; urgency=medium

  * debian/control:
    - Revert BD on adwaita-icon-theme 3.36.1-2ubuntu3. It was just temporary fix
  * d/p/x11-Add-support-for-fractional-scaling-using-Randr.patch:
    - Use pre-computed CRTC layout size for computing screen size (LP: #1874567,
      LP: #1873403)
    - Decouple the output mode from layout mode capabilities (LP: #1876894,
      LP: #1886996)
    - Ensure we notify CRTC changes on integer scaling changes (LP: #1876894)
    - Apply proper layout monitor config when using fractional scaling
      (LP: #1884754)
    - Restore the fractional settings when reverting to fractional layout
      (LP: #1886996)
  * debian/libmutter-6-0.symbols: Add new private symbol

 -- Marco Trevisan (Treviño) <email address hidden> Mon, 27 Jul 2020 17:04:41 +0200

The verification of the Stable Release Update for mutter has completed successfully and the package is now being 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.

Hello errors.ubuntu.com, or anyone else affected,

Accepted mutter into focal-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/mutter/3.36.6-1ubuntu0.20.04.1 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, what testing has been performed on the package and change the tag from verification-needed-focal to verification-done-focal. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-focal. 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.

This bug has been already fixed as part of 3.36.4-0ubuntu0.20.04.2, and opened by the SRU tool as it is included again in the changelog as it's being part of a debian release we've merged with.

So marking as verified (as discussed with SRU team)

Hello errors.ubuntu.com, or anyone else affected,

Accepted mutter into focal-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/mutter/3.36.6-1ubuntu0.20.04.2 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, what testing has been performed on the package and change the tag from verification-needed-focal to verification-done-focal. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-focal. 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.

As per comment https://bugs.launchpad.net/mutter/+bug/1857947/comments/11

We can mark this as verified.

This bug was fixed in the package mutter - 3.36.6-1ubuntu0.20.04.2

---------------
mutter (3.36.6-1ubuntu0.20.04.2) focal; urgency=medium

  * xrandr-scaling: Never try to set invalid screen sizes (again!)
    Looks like this change (introduced to fix LP:1889090) got lost while
    rebasing previous fixes, gbp has been a bad guy this time! (LP: #1896818)

mutter (3.36.6-1ubuntu0.20.04.1) focal; urgency=medium

  * Merge with debian, containing new stable release (LP: #1896332)
  * debian/patches:
    - Refresh patches and drop applied ones
    - Don't set the font-dpi on clutter-backend-x11 (LP: #1892440)
    - Cherry-pick upstream night-switch fixes for 3.36 branch
    - Cherry-pick upstream fixes for handling X11 devices removal
      (LP: #1558886)
  * xrandr-scaling: Don't update UI scale factor on xrandr-manager creation
    (LP: #1892440)
  * debian/control: Revert pipewire version bumping
  * Remaining changes with debian:
    - debian/control:
      + Update VCS flags to point to ubuntu salsa branch
    - debian/gbp.conf: update branch to point to ubuntu/master
    - debian/patches/x11-Add-support-for-fractional-scaling-using-Randr.patch:
      + X11: Add support for fractional scaling using Randr

mutter (3.36.6-1) unstable; urgency=medium

  * Team upload
  * New upstream release
  * Update symbols file
  * d/control.in, d/rules: Enable Pipewire on Debian (but not Ubuntu).
    Now that we have Pipewire 0.3, we can enable screencasting and remote
    desktop support again.

mutter (3.36.5-1) unstable; urgency=medium

  * Team upload
  * New upstream release
    - Screencast fixes and improvements
    - Fix glitches when subsurfaces extend outside the toplevel
    - Improve background display in overview workspace switcher
    - Fix wine copy & paste
    - Plug memory leaks
  * Drop patches that were applied upstream

mutter (3.36.4-1) unstable; urgency=medium

  * New upstream stable release (LP: #1887998)
    - Fix crash on area screenshots with fractional scaling
    - Do not paint textures of fully obscured windows
    - Turn off CRTCs as well when enabling DPMS
    - Improve selection support
    - Use a more appropriate combine function on opaque areas
    - Fix remote desktop being broken without screencast session
    - Fix popovers disappearing on wayland and HiDPI
    - Fixed crashes (LP: #1870867, LP: #1857947)
    - Plugged memory leaks
  * d/p/screen-cast-Let-the-reason-for-recording-determine-what-t.patch,
    d/p/screen-cast-src-Add-flag-to-maybe_record.patch,
    d/p/screen-cast-src-Fix-signedness-of-timestamp-field.patch,
    d/p/screen-cast-src-Make-record-functions-return-an-error-whe.patch,
    d/p/screen-cast-src-Make-the-two-record-vfuncs-more-similarly.patch,
    d/p/screen-cast-src-Record-follow-up-frame-after-timeout.patch,
    d/p/screen-cast-src-Remove-follow-up-timeout-source-on-disabl.patch,
    d/p/screen-cast-src-Use-G_USEC_PER_SEC-instead-of-1000000.patch,
    d/p/screen-cast-window-stream-src-Fix-indentation.patch:
    - Import more fixes for screencasting and remote desktop

 -- Marco Trevisan (Treviño) <email address hidden> Wed, 23 Sep 2020 22:03:53 +0200