gnome crashes when trying to lock session

[ShadowGoblet]

When trying to lock session, either through key combination or clicking 'lock' in the top right menu, gnome unexpectedly freezes. During the time it's freezed I can move the mouse freely, but everything stops (even the clock). After some time it seems to restart because it flashes and everything goes back to normal. After the crash if I try to relock it again it works, but if I try after that the cycle repeats.
Sometimes after the crash a crash report window launches accusing a SIGSEGV in gnome-shell.
Looking at Logs I can see that the main process was exited and that the core was dumped.
Note that at the time it freezes gnome unexpectedly switches the active window.

I'm running Ubuntu 20.04 LTS with gnome-shell version 3.36.2-1ubuntu1~20.04.1

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: gnome-shell 3.36.2-1ubuntu1~20.04.1
ProcVersionSignature: Ubuntu 5.4.0-33.37-generic 5.4.34
Uname: Linux 5.4.0-33-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.2
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Mon Jun 8 17:49:56 2020
DisplayManager: gdm3
InstallationDate: Installed on 2020-05-06 (33 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
RelatedPackageVersions: mutter-common 3.36.2-1ubuntu1~20.04.1
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install)

[Sebastien Bacher (seb128)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It sounds like some part of the system has crashed. To help us find the cause of the crash please follow these steps:

1. Look in /var/crash for crash files and if found run:
    ubuntu-bug YOURFILE.crash
Then tell us the ID of the newly-created bug.

2. If step 1 failed then look at https://errors.ubuntu.com/user/ID where ID is the content of file /var/lib/whoopsie/whoopsie-id on the machine. Do you find any links to recent problems on that page? If so then please send the links to us.

3. If step 2 also failed then apply the workaround from bug 994921, reboot, reproduce the crash, and retry step 1.

Please take care to avoid attaching .crash files to bugs as we are unable to process them as file attachments. It would also be a security risk for yourself.

[Daniel van Vugt (vanvugt)]

Note this is *probably* bug 1877774.

[ShadowGoblet (shadowgoblet)]

I'm sorry,
Indeed, this seems exatcly bug 1877774, with SIGSEGV occuring on st_theme_ensure_background.
In spite of that, I couldn't figure out if the bug has been solved since my system is already up-to-date.

Thank you for your attention and fast response,

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Tuesday, 9 June 2020 05:32, Daniel van Vugt <email address hidden> wrote:

> Note this is probably bug 1877774.
>
> -----------------------------------
>
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1882585
>
> Title:
> gnome crashes when trying to lock session
>
> Status in gnome-shell package in Ubuntu:
> Invalid
>
> Bug description:
> When trying to lock session, either through key combination or clicking 'lock' in the top right menu, gnome unexpectedly freezes. During the time it's freezed I can move the mouse freely, but everything stops (even the clock). After some time it seems to restart because it flashes and everything goes back to normal. After the crash if I try to relock it again it works, but if I try after that the cycle repeats.
> Sometimes after the crash a crash report window launches accusing a SIGSEGV in gnome-shell.
> Looking at Logs I can see that the main process was exited and that the core was dumped.
> Note that at the time it freezes gnome unexpectedly switches the active window.
>
> I'm running Ubuntu 20.04 LTS with gnome-shell version
> 3.36.2-1ubuntu1~20.04.1
>
> ProblemType: Bug
> DistroRelease: Ubuntu 20.04
> Package: gnome-shell 3.36.2-1ubuntu1~20.04.1
> ProcVersionSignature: Ubuntu 5.4.0-33.37-generic 5.4.34
> Uname: Linux 5.4.0-33-generic x86_64
> NonfreeKernelModules: nvidia_modeset nvidia
> ApportVersion: 2.20.11-0ubuntu27.2
> Architecture: amd64
> CasperMD5CheckResult: skip
> CurrentDesktop: ubuntu:GNOME
> Date: Mon Jun 8 17:49:56 2020
> DisplayManager: gdm3
> InstallationDate: Installed on 2020-05-06 (33 days ago)
> InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
> RelatedPackageVersions: mutter-common 3.36.2-1ubuntu1~20.04.1
> SourcePackage: gnome-shell
> UpgradeStatus: No upgrade log present (probably fresh install)
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1882585/+subscriptions