Xwayland crashes after unlocking screen

[Lars]

When I unlock the screen from screensaver sometimes, but not always, Xwayland coredumps.

$ gdb /usr/bin/Xwayland ~/core
GNU gdb (Ubuntu 8.0.1-0ubuntu1) 8.0.1
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Reading symbols from /usr/bin/Xwayland...(no debugging symbols found)...done.
[New LWP 6786]
[New LWP 6787]
[New LWP 6790]
[New LWP 6788]
[New LWP 6789]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `/usr/bin/Xwayland :0 -rootless -terminate -core -listen 4 -listen 5 -displayfd'.
Program terminated with signal SIGABRT, Aborted.
#0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
51 ../sysdeps/unix/sysv/linux/raise.c: No such file or directory.
[Current thread is 1 (Thread 0x7f9140a68a80 (LWP 6786))]
(gdb) bt full
#0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
        set = {__val = {171515904, 0, 0, 0, 0, 140261709342601, 94745322873264, 67108868, 140261785854288, 0, 94745365252208, 94745321417623,
            0, 94745348741304, 94745366391120, 94745365252128}}
        pid = <optimized out>
        tid = <optimized out>
#1 0x00007f913db03f5d in __GI_abort () at abort.c:90
        save_stage = 2
        act = {__sigaction_handler = {sa_handler = 0x0, sa_sigaction = 0x0}, sa_mask = {__val = {94745348741304, 94745366391120,
              94745365252128, 140720405293760, 140720405293764, 12884901928, 94745363065648, 0, 7425099061155604736, 0, 94745363176736, 11,
              67108868, 140261785854288, 7425099061155604736, 0}}, sa_flags = -1655605696, sa_restorer = 0x7ffc05c52cb0}
        sigs = {__val = {32, 0 <repeats 15 times>}}
#2 0x0000562b9d50913a in OsAbort ()
No symbol table info available.
#3 0x0000562b9d50ec53 in ?? ()
No symbol table info available.
#4 0x0000562b9d50fa75 in FatalError ()
No symbol table info available.
#5 0x0000562b9d39543f in ?? ()
No symbol table info available.
#6 0x0000562b9d506cb1 in ?? ()
No symbol table info available.
#7 0x0000562b9d4ffcbb in WaitForSomething ()
No symbol table info available.
#8 0x0000562b9d4cb9f3 in ?? ()
No symbol table info available.
#9 0x0000562b9d4cfc90 in ?? ()
No symbol table info available.
#10 0x00007f913daec1c1 in __libc_start_main (main=0x562b9d394a60, argc=11, argv=0x7ffc05c53be8, init=<optimized out>, fini=<optimized out>,
    rtld_fini=<optimized out>, stack_end=0x7ffc05c53bd8) at ../csu/libc-start.c:308
        result = <optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {0, 8252881868666068147, 94745321359984, 140720405298144, 0, 0, 2388897359761923251,
                2449221155427998899}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x7ffc05c53c48, 0x7f9140abc150}, data = {prev = 0x0,
              cleanup = 0x0, canceltype = 96812104}}}
        not_first_call = <optimized out>
#11 0x0000562b9d394a9a in _start ()
No symbol table info available.

Any idea what is going on here?

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: xwayland 2:1.19.5-0ubuntu2
ProcVersionSignature: Ubuntu 4.13.0-25.29-generic 4.13.13
Uname: Linux 4.13.0-25-generic x86_64
NonfreeKernelModules: zfs zunicode zavl zcommon znvpair
.tmp.unity_support_test.0:

ApportVersion: 2.20.7-0ubuntu3.7
Architecture: amd64
CompizPlugins: [core,composite,opengl,imgjpeg,decor,mousepoll,move,compiztoolbox,regex,place,commands,imgpng,grid,gnomecompat,dbus,resize,screenshot,animation,session,fade,cube,workarounds,rotate,scale,unitymtgrabhandles,expo,unityshell]
CompositorRunning: None
CurrentDesktop: GNOME
Date: Thu Jan 11 17:02:07 2018
DistUpgraded: Fresh install
DistroCodename: artful
DistroVariant: ubuntu
EcryptfsInUse: Yes
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0126] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Lenovo 2nd Generation Core Processor Family Integrated Graphics Controller (ThinkPad T520) [17aa:21cf]
MachineType: LENOVO 4240CTO
ProcKernelCmdLine: BOOT_IMAGE=/ROOT/ubuntu-15.04@/boot/vmlinuz-4.13.0-25-generic root=ZFS=rpool/ROOT/ubuntu-15.04 ro quiet splash nomdmonddf nomdmonisw vt.handoff=7
SourcePackage: xorg-server
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/26/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: 8AET64WW (1.44 )
dmi.board.asset.tag: Not Available
dmi.board.name: 4240CTO
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr8AET64WW(1.44):bd07/26/2013:svnLENOVO:pn4240CTO:pvrThinkPadT520:rvnLENOVO:rn4240CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.family: ThinkPad T520
dmi.product.name: 4240CTO
dmi.product.version: ThinkPad T520
dmi.sys.vendor: LENOVO
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.83-1
version.libgl1-mesa-dri: libgl1-mesa-dri 17.2.4-0ubuntu1~17.10.1
version.libgl1-mesa-glx: libgl1-mesa-glx 17.2.4-0ubuntu1~17.10.1
version.xserver-xorg-core: xserver-xorg-core 2:1.19.5-0ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.5-1ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.10.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20170309-0ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-2
xserver.bootTime: Wed Dec 6 12:19:49 2017
xserver.configfile: default
xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.19.5-0ubuntu2

[Launchpad Janitor (janitor)]

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