Xwayland crashed with SIGSEGV in dixGetPrivate() from dixLookupPrivate() from present_screen_priv() from present_wnmd_flip() from present_wnmd_execute() from present_wnmd_event_notify() from xwl_present_events_notify() from xwl_present_timer_callback()

[John]

I have some daisy-chained DisplayPort monitors connected via a DisplayPort KVM switch. This crash occurs at the moment the switch is switched "away" from host 1 to another host. Upon switching back to host 1, the gnome-session & gui processes have exited and the login screen is displayed. Makes it difficult to get much work done.

ProblemType: Crash
DistroRelease: Ubuntu 18.10
Package: xwayland 2:1.20.1-3ubuntu2.1
Uname: Linux 4.20.0-042000-generic x86_64
.tmp.unity_support_test.0:

ApportVersion: 2.20.10-0ubuntu13.1
Architecture: amd64
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Tue Jan 8 17:44:27 2019
DistUpgraded: 2018-10-25 13:46:36,654 DEBUG Running PostInstallScript: './xorg_fix_proprietary.py'
DistroCodename: cosmic
DistroVariant: ubuntu
ExecutablePath: /usr/bin/Xwayland
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation Iris Pro Graphics 580 [8086:193b] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Intel Corporation Iris Pro Graphics 580 [8086:2064]
InstallationDate: Installed on 2016-10-05 (825 days ago)
InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
ProcCmdline: /usr/bin/Xwayland :0 -rootless -terminate -accessx -core -listen 4 -listen 5 -displayfd 6
ProcEnviron:
 LANGUAGE=en_CA:en
 PATH=(custom, user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_CA.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.20.0-042000-generic root=/dev/mapper/ubuntu--vg-root ro splash crashkernel=512M-:192M vt.handoff=1
Signal: 6
SourcePackage: xorg-server
StacktraceTop:
 ?? ()
 ?? ()
 ?? ()
 ?? ()
 ?? ()
Title: Xwayland crashed with SIGABRT
UpgradeStatus: Upgraded to cosmic on 2018-10-25 (75 days ago)
UserGroups: adm cdrom dip docker lpadmin plugdev sambashare sudo wireshark
dmi.bios.date: 05/16/2018
dmi.bios.vendor: Intel Corp.
dmi.bios.version: KYSKLi70.86A.0055.2018.0516.1629
dmi.board.name: NUC6i7KYB
dmi.board.vendor: Intel Corporation
dmi.board.version: H90766-404
dmi.chassis.type: 3
dmi.chassis.vendor: Intel Corporation
dmi.chassis.version: 1.0
dmi.modalias: dmi:bvnIntelCorp.:bvrKYSKLi70.86A.0055.2018.0516.1629:bd05/16/2018:svn:pn:pvr:rvnIntelCorporation:rnNUC6i7KYB:rvrH90766-404:cvnIntelCorporation:ct3:cvr1.0:
mtime.conffile..etc.apport.crashdb.conf: 2019-01-08T10:58:28.409903
version.compiz: compiz 1:0.9.13.1+18.10.20180930-0ubuntu1
version.libdrm2: libdrm2 2.4.95-1
version.libgl1-mesa-dri: libgl1-mesa-dri 18.2.2-0ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx 18.2.2-0ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.20.1-3ubuntu2.1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.6-1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:18.1.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20171229-1ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-3
xserver.bootTime: Mon Nov 5 11:41:45 2018
xserver.configfile: default
xserver.errors:
 open /dev/dri/card0: No such file or directory
 open /dev/dri/card0: No such file or directory
 Screen 0 deleted because of no matching config section.
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:

xserver.version: 2:1.20.1-3ubuntu2.1

[John (john-e-francis)]

originally described in bug 1801110

[Apport retracing service (apport)]

StacktraceTop:
 dixGetPrivate (key=<optimized out>, privates=0x3000003d0) at ../../../../include/privates.h:122
 dixLookupPrivate (key=<optimized out>, privates=0x3000003d0) at ../../../../include/privates.h:166
 present_screen_priv (screen=0x300000000) at ../../../../present/present_priv.h:198
 present_wnmd_flip (damage=0x561e7959c1d0, sync_flip=1, pixmap=0x561e794b8b60, target_msc=10695, event_id=21050, crtc=0x561e7965fe30, window=0x561e7959c180) at ../../../../present/present_wnmd.c:357
 present_wnmd_execute (vblank=0x561e78f2b750, ust=4919664407, crtc_msc=10694) at ../../../../present/present_wnmd.c:465

[Daniel van Vugt (vanvugt)]

I couldn't find any existing reports of this crash. Although bug 1811024 and bug 1811025 look related.

[Launchpad Janitor (janitor)]

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

[Daniel van Vugt (vanvugt)]

Thank you for reporting this bug to Ubuntu.
Ubuntu 18.10 (cosmic) reached end-of-life on July 18, 2019.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test. If you then find the bug is still present in the newer Ubuntu version, please add a comment here telling us which new version it is in and change the bug status to Confirmed.