WL: compositor bug: The compositor tried to use an object from one client in a 'wl_pointer.enter' for a different client (resulting in Gnome terminal crashing)

[Jani Uusitalo]

Since upgrading to 20.04 and switching to Wayland, Gnome terminal occasionally crashes. I interpret the corresponding logs to mean that it's actually Wayland that fails to do something in the background, which then takes down Gnome terminal:

    touko 08 11:35:16 saegusa gnome-shell[4227]: WL: compositor bug: The compositor tried to use an object from one client in a 'wl_pointer.enter' for a different client.
    touko 08 11:35:16 saegusa gnome-shell[4227]: WL: error in client communication (pid 11639)
    touko 08 11:35:16 saegusa gnome-terminal-[11639]: Error reading events from display: Katkennut putki
    touko 08 11:35:16 saegusa systemd[4153]: vte-spawn-bbca1723-5987-4ccf-98cb-3389ad05641e.scope: Succeeded.
    touko 08 11:35:16 saegusa systemd[4153]: vte-spawn-fbe02208-95df-4cf4-bfbe-fffc71d6bc7e.scope: Succeeded.
    touko 08 11:35:16 saegusa systemd[4153]: gnome-terminal-server.service: Main process exited, code=exited, status=1/FAILURE
    touko 08 11:35:16 saegusa systemd[4153]: gnome-terminal-server.service: Failed with result 'exit-code'.

I have yet to nail down the precise circumstances, as this has (so far) been somewhat rare, having occurred perhaps once or twice a week.

Since the log mentions pointer, I should perhaps mention that I've set `org.gnome.desktop.wm.preferences` > `focus-mode` to `mouse`. Gnome terminal also exhibits other misbehaviour wrt. to this, occasionally refusing to get focus, or alternatively losing the focus, despite mouse cursor being over the terminal window.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: xwayland 2:1.20.8-2ubuntu2
ProcVersionSignature: Ubuntu 5.4.0-30.34-generic 5.4.34
Uname: Linux 5.4.0-30-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CompizPlugins: [core,composite,opengl,compiztoolbox,decor,gnomecompat,snap,imgpng,unitymtgrabhandles,move,place,grid,resize,mousepoll,vpswitch,regex,winrules,wall,session,animation,workarounds,expo,ezoom,fade,scale,unityshell]
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Fri May 8 15:22:28 2020
DistUpgraded: Fresh install
DistroCodename: focal
DistroVariant: ubuntu
DkmsStatus:
 fwts-efi-runtime-dkms, 20.03.00, 5.4.0-29-generic, x86_64: installed (WARNING! Diff between built and installed module!)
 fwts-efi-runtime-dkms, 20.03.00, 5.4.0-30-generic, x86_64: installed (WARNING! Diff between built and installed module!)
 xtables-addons, 3.8, 5.4.0-29-generic, x86_64: installed
 xtables-addons, 3.8, 5.4.0-30-generic, x86_64: installed
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller [8086:0162] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: ASUSTeK Computer Inc. P8 series motherboard [1043:84ca]
InstallationDate: Installed on 2016-10-13 (1302 days ago)
InstallationMedia: Ubuntu-Server 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
MachineType: System manufacturer System Product Name
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=fi_FI.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-30-generic root=UUID=45ed9550-28e7-4af4-a625-9f31663dce9b ro quiet splash vt.handoff=7
SourcePackage: xorg-server
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/17/2014
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1505
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: P8H77-M PRO
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev X.0x
dmi.chassis.asset.tag: Asset-1234567890
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr1505:bd10/17/2014:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnP8H77-MPRO:rvrRevX.0x:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.family: To be filled by O.E.M.
dmi.product.name: System Product Name
dmi.product.sku: SKU
dmi.product.version: System Version
dmi.sys.vendor: System manufacturer
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.101-2
version.libgl1-mesa-dri: libgl1-mesa-dri 20.0.4-2ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx 20.0.4-2ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.20.8-2ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.6-1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20200226-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.16-1
xserver.bootTime: Tue Mar 20 15:09:56 2018
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.19.5-0ubuntu2~16.04.1
xserver.video_driver: modeset

[Daniel van Vugt (vanvugt)]

Please also follow these instructions to help us identify the crash:

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.

[Jani Uusitalo (uusijani)]

Thanks for the instructions, Daniel! I found no crash files either locally or online, so I've implemented the workaround now, and will try to trigger the crash again.

[Jani Uusitalo (uusijani)]

Turns out the online service was just a little slow to update, and there are in fact reports sent. But the only one post-20.04-upgrade is [1] from last week, which is a gnome-shell crash and IIRC, unrelated to the terminal issue here. It seemed to be triggered by something related to media files and Nautilus, and the logs from the time are different; I'm attaching them here. (I had separated gnome-shell logs out from the main syslog, but I've since reverted back to having everything in syslog.)

* [1] https://errors.ubuntu.com/oops/26828e26-8fc9-11ea-acd0-fa163e983629

[Jani Uusitalo (uusijani)]

Happened again:

    May 11 17:05:50 saegusa gnome-shell[3619]: WL: compositor bug: The compositor tried to use an object from one client in a 'wl_pointer.enter' for a different client.
    May 11 17:05:50 saegusa gnome-shell[3619]: WL: error in client communication (pid 5170)
    May 11 17:05:50 saegusa gnome-terminal-[5170]: Error reading events from display: Katkennut putki
    May 11 17:05:50 saegusa systemd[3544]: gnome-terminal-server.service: Main process exited, code=exited, status=1/FAILURE
    May 11 17:05:50 saegusa systemd[3544]: gnome-terminal-server.service: Failed with result 'exit-code'.
    May 11 17:05:50 saegusa systemd[3544]: vte-spawn-b269c64d-5376-49ec-83fc-9f4806ac4b30.scope: Succeeded.
    May 11 17:05:50 saegusa systemd[3544]: vte-spawn-3294a176-7b32-4995-a11b-fe0fea8b07bc.scope: Succeeded.
    May 11 17:05:50 saegusa systemd[3544]: vte-spawn-0b59afd0-1aed-4081-a7d1-801e7c405399.scope: Succeeded.
    May 11 17:05:51 saegusa systemd[3544]: Started Application launched by gnome-shell.

But there's still nothing in /var/crash, nor on the Error Tracker (aside from the aforementioned, unrelated crash from last week).

[Daniel van Vugt (vanvugt)]

If it is a compositor bug as the Wayland library is suggesting then next please try uninstalling all non-Ubuntu gnome-shell extensions, and reboot.

[Jani Uusitalo (uusijani)]

I removed all but Desktop Icons, Ubuntu AppIndicators and Ubuntu Dock, rebooted and then reproduced the issue. Luckily I've found one way to reproduce this, albeit somewhat convoluted and still a bit unreliable, involving Synaptic and window tiling. And as it doesn't seem to trigger the issue when using another account, I'm now working through settings differences between the two in hopes of finding something crucial.

While doing so, I did discover that dconf-editor is similarly affected:

    touko 12 16:09:32 saegusa gnome-shell[8208]: WL: compositor bug: The compositor tried to use an object from one client in a 'wl_pointer.enter' for a different client.
    touko 12 16:09:32 saegusa gnome-shell[8208]: WL: error in client communication (pid 12364)
    touko 12 16:09:32 saegusa dconf-editor[12364]: Error reading events from display: Katkennut putki
    touko 12 16:09:32 saegusa boinc[2098]: No protocol specified
    touko 12 16:09:32 saegusa boinc[2098]: No protocol specified
    touko 12 16:09:33 saegusa boinc[2098]: No protocol specified
    touko 12 16:09:33 saegusa boinc[2098]: No protocol specified
    touko 12 16:09:34 saegusa gnome-shell[8208]: WL: compositor bug: The compositor tried to use an object from one client in a 'wl_pointer.enter' for a different client.
    touko 12 16:09:34 saegusa boinc[2098]: No protocol specified
    touko 12 16:09:34 saegusa boinc[2098]: No protocol specified
    touko 12 16:09:34 saegusa gnome-shell[8208]: WL: error in client communication (pid 12796)
    touko 12 16:09:34 saegusa gnome-terminal-[12796]: Error reading events from display: Katkennut putki
    touko 12 16:09:34 saegusa systemd[3569]: gnome-terminal-server.service: Main process exited, code=exited, status=1/FAILURE
    touko 12 16:09:34 saegusa systemd[3569]: gnome-terminal-server.service: Failed with result 'exit-code'.
    touko 12 16:09:34 saegusa systemd[3569]: vte-spawn-da1941e8-60e5-48e5-868b-7348dd1158c7.scope: Succeeded.
    touko 12 16:09:34 saegusa gnome-shell[8208]: Error adding children to desktop: this.layout.get_child_at(...) is null
    touko 12 16:09:34 saegusa gnome-shell[8208]: Error adding children to desktop: this.layout.get_child_at(...) is null
    touko 12 16:09:34 saegusa gnome-shell[8208]: Error adding children to desktop: this.layout.get_child_at(...) is null
    touko 12 16:09:34 saegusa gnome-shell[8208]: Error adding children to desktop: this.layout.get_child_at(...) is null

Looks like dconf-editor did not exit with FAILURE, but the dconf-editor window did disappear just as Gnome terminal's did.

[Daniel van Vugt (vanvugt)]

Please report the bug to the Mutter developers at:

  https://gitlab.gnome.org/GNOME/mutter/-/issues

and then tell us the new issue ID.

[Jani Uusitalo (uusijani)]

After doing manual dconf cleanup, I've been unable to reproduce the issue. That's since posting the previous comment, so a few days now. So I think I'll hold off on reporting this upstream for the time being, but I'll go ahead and do that if the problem still manifests itself.

Thanks again, Daniel.

[Daniel van Vugt (vanvugt)]

No problem. The bug will automatically close after 60 days of no comments.

[Launchpad Janitor (janitor)]

[Expired for mutter (Ubuntu) because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for wayland (Ubuntu) because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for gnome-terminal (Ubuntu) because there has been no activity for 60 days.]