I can reproduce this too, Debian testing.
Oct 19 14:15:47 patanjali org.gnome.Shell.desktop[1601]: libinput error: client bug: timer event4 trackpoint: offset negative (-28ms)
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE)
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) Backtrace:
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) 0: /usr/bin/Xwayland (OsLookupColor+0x139) [0x55ba9deb4a69]
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) 1: /lib/x86_64-linux-gnu/libpthread.so.0 (funlockfile+0x50) [0x7f1110d9292f]
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) 2: /usr/bin/Xwayland (present_extension_init+0xce6) [0x55ba9de1d316]
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) 3: /usr/bin/Xwayland (glamor_egl_fd_from_pixmap+0x390) [0x55ba9dd5f380]
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) 4: /usr/bin/Xwayland (glamor_egl_fd_from_pixmap+0x533) [0x55ba9dd5f6f3]
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) 5: /usr/bin/Xwayland (TimerSet+0x180) [0x55ba9deae2e0]
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) 6: /usr/bin/Xwayland (TimerSet+0x1f8) [0x55ba9deae3a8]
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) 7: /usr/bin/Xwayland (WaitForSomething+0x277) [0x55ba9deae487]
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) 8: /usr/bin/Xwayland (SendErrorToClient+0x10c) [0x55ba9de7e85c]
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) 9: /usr/bin/Xwayland (InitFonts+0x3b6) [0x55ba9de82a36]
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) 10: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xe7) [0x7f1110be5b17]
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) 11: /usr/bin/Xwayland (_start+0x2a) [0x55ba9dd541ea]
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE)
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) Segmentation fault at address 0x0
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE)
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: Fatal server error:
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE) Caught signal 11 (Segmentation fault). Server aborting
Oct 19 14:15:53 patanjali org.gnome.Shell.desktop[1601]: (EE)
PID: 1627 (Xwayland)
UID: 1000 (claudio)
GID: 1000 (claudio)
Signal: 6 (ABRT)
Timestamp: Fri 2018-10-19 14:15:53 EEST (7min ago)
Command Line: /usr/bin/Xwayland :0 -rootless -terminate -accessx -core -listen 4 -listen 5 -displayfd 6
Executable: /usr/bin/Xwayland
Control Group: /user.slice/user-1000.slice/session-4.scope
Unit: session-4.scope
Slice: user-1000.slice
Session: 4
Owner UID: 1000 (claudio)
Boot ID: b12903cc16ef496d862aeeb2aea70027
Machine ID: 60331354e4294207860fddfd176ae49c
Hostname: patanjali
Storage: /var/lib/systemd/coredump/core.Xwayland.1000.b12903cc16ef496d862aeeb2aea70027.1627.1539947753000000.lz4
Message: Process 1627 (Xwayland) of user 1000 dumped core.
Stack trace of thread 1627:
#0 0x00007f1110bf8f3b __GI_raise (libc.so.6)
#1 0x00007f1110bfa2f1 __GI_abort (libc.so.6)
#2 0x000055ba9deb758a OsAbort (Xwayland)
#3 0x000055ba9debd093 n/a (Xwayland)
#4 0x000055ba9debdef9 FatalError (Xwayland)
#5 0x000055ba9deb49a1 n/a (Xwayland)
#6 0x00007f1110d928e0 __restore_rt (libpthread.so.0)
#7 0x000055ba9de1c7f6 n/a (Xwayland)
#8 0x000055ba9dd5f050 n/a (Xwayland)
#9 0x000055ba9dd5f1f3 n/a (Xwayland)
#10 0x000055ba9deae180 n/a (Xwayland)
#11 0x000055ba9deae1f8 n/a (Xwayland)
#12 0x000055ba9deae487 WaitForSomething (Xwayland)
#13 0x000055ba9de7e7fc n/a (Xwayland)
#14 0x000055ba9de829f6 n/a (Xwayland)
#15 0x00007f1110be5b17 __libc_start_main (libc.so.6)
#16 0x000055ba9dd541ea _start (Xwayland)
Stack trace of thread 1629:
#0 0x00007f1110d8de6c futex_wait_cancelable (libpthread.so.0)
#1 0x00007f110d90627b n/a (swrast_dri.so)
#2 0x00007f110d9061d7 n/a (swrast_dri.so)
#3 0x00007f1110d87f2a start_thread (libpthread.so.0)
#4 0x00007f1110cbaedf __clone (libc.so.6)
Stack trace of thread 1631:
#0 0x00007f1110d8de6c futex_wait_cancelable (libpthread.so.0)
#1 0x00007f110d90627b n/a (swrast_dri.so)
#2 0x00007f110d9061d7 n/a (swrast_dri.so)
#3 0x00007f1110d87f2a start_thread (libpthread.so.0)
#4 0x00007f1110cbaedf __clone (libc.so.6)
Stack trace of thread 1630:
#0 0x00007f1110d8de6c futex_wait_cancelable (libpthread.so.0)
#1 0x00007f110d90627b n/a (swrast_dri.so)
#2 0x00007f110d9061d7 n/a (swrast_dri.so)
#3 0x00007f1110d87f2a start_thread (libpthread.so.0)
#4 0x00007f1110cbaedf __clone (libc.so.6)
Stack trace of thread 1632:
#0 0x00007f1110d8de6c futex_wait_cancelable (libpthread.so.0)
#1 0x00007f110d90627b n/a (swrast_dri.so)
#2 0x00007f110d9061d7 n/a (swrast_dri.so)
#3 0x00007f1110d87f2a start_thread (libpthread.so.0)
#4 0x00007f1110cbaedf __clone (libc.so.6)
Stack trace of thread 1628:
#0 0x00007f1110d8de6c futex_wait_cancelable (libpthread.so.0)
#1 0x00007f110eee1d8b n/a (i965_dri.so)
#2 0x00007f110eee1ab7 n/a (i965_dri.so)
#3 0x00007f1110d87f2a start_thread (libpthread.so.0)
#4 0x00007f1110cbaedf __clone (libc.so.6)
GNU gdb (Debian 8.1-4+b1) 8.1
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
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Reading symbols from /usr/bin/Xwayland...Reading symbols from /usr/lib/debug/.build-id/4b/d0101c0a89af2f37ed7cb48b6dc5f8c1347f77.debug...done.
done.
[New LWP 1627]
[New LWP 1629]
[New LWP 1631]
[New LWP 1630]
[New LWP 1632]
[New LWP 1628]
[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 -accessx -core -listen 4 -listen 5 -d'.
Program terminated with signal SIGABRT, Aborted.
#0 __GI_raise (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 0x7f110f6c7a80 (LWP 1627))]
(gdb) thread apply all bt
Thread 6 (Thread 0x7f110e694700 (LWP 1628)):
#0 0x00007f1110d8de6c in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55ba9ea0eec0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1 __pthread_cond_wait_common (abstime=0x0, mutex=0x55ba9ea0ee70, cond=0x55ba9ea0ee98) at pthread_cond_wait.c:502
#2 __pthread_cond_wait (cond=0x55ba9ea0ee98, mutex=0x55ba9ea0ee70) at pthread_cond_wait.c:655
#3 0x00007f110eee1d8b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4 0x00007f110eee1ab7 in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5 0x00007f1110d87f2a in start_thread (arg=0x7f110e694700) at pthread_create.c:463
#6 0x00007f1110cbaedf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
Thread 5 (Thread 0x7f1103417700 (LWP 1632)):
#0 0x00007f1110d8de6c in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55ba9eac8df8) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1 __pthread_cond_wait_common (abstime=0x0, mutex=0x55ba9eac8da8, cond=0x55ba9eac8dd0) at pthread_cond_wait.c:502
#2 __pthread_cond_wait (cond=0x55ba9eac8dd0, mutex=0x55ba9eac8da8) at pthread_cond_wait.c:655
#3 0x00007f110d90627b in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#4 0x00007f110d9061d7 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#5 0x00007f1110d87f2a in start_thread (arg=0x7f1103417700) at pthread_create.c:463
#6 0x00007f1110cbaedf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
Thread 4 (Thread 0x7f1104419700 (LWP 1630)):
#0 0x00007f1110d8de6c in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55ba9eac8b28) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1 __pthread_cond_wait_common (abstime=0x0, mutex=0x55ba9eac8ad8, cond=0x55ba9eac8b00) at pthread_cond_wait.c:502
#2 __pthread_cond_wait (cond=0x55ba9eac8b00, mutex=0x55ba9eac8ad8) at pthread_cond_wait.c:655
#3 0x00007f110d90627b in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#4 0x00007f110d9061d7 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#5 0x00007f1110d87f2a in start_thread (arg=0x7f1104419700) at pthread_create.c:463
#6 0x00007f1110cbaedf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
Thread 3 (Thread 0x7f1103c18700 (LWP 1631)):
#0 0x00007f1110d8de6c in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55ba9eac8c90) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1 __pthread_cond_wait_common (abstime=0x0, mutex=0x55ba9eac8c40, cond=0x55ba9eac8c68) at pthread_cond_wait.c:502
#2 __pthread_cond_wait (cond=0x55ba9eac8c68, mutex=0x55ba9eac8c40) at pthread_cond_wait.c:655
#3 0x00007f110d90627b in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#4 0x00007f110d9061d7 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#5 0x00007f1110d87f2a in start_thread (arg=0x7f1103c18700) at pthread_create.c:463
#6 0x00007f1110cbaedf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
Thread 2 (Thread 0x7f110ca01700 (LWP 1629)):
#0 0x00007f1110d8de6c in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55ba9eac89c0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1 __pthread_cond_wait_common (abstime=0x0, mutex=0x55ba9eac8970, cond=0x55ba9eac8998) at pthread_cond_wait.c:502
#2 __pthread_cond_wait (cond=0x55ba9eac8998, mutex=0x55ba9eac8970) at pthread_cond_wait.c:655
#3 0x00007f110d90627b in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#4 0x00007f110d9061d7 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#5 0x00007f1110d87f2a in start_thread (arg=0x7f110ca01700) at pthread_create.c:463
#6 0x00007f1110cbaedf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
Thread 1 (Thread 0x7f110f6c7a80 (LWP 1627)):
#0 __GI_raise (sig=***@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
#1 0x00007f1110bfa2f1 in __GI_abort () at abort.c:79
#2 0x000055ba9deb758a in OsAbort () at ../../../../os/utils.c:1350
#3 0x000055ba9debd093 in AbortServer () at ../../../../os/log.c:877
#4 0x000055ba9debdef9 in FatalError (f=***@entry=0x55ba9dee1050 "Caught signal %d (%s). Server aborting\n") at ../../../../os/log.c:1015
#5 0x000055ba9deb49a1 in OsSigHandler (signo=11, sip=<optimized out>, unused=<optimized out>) at ../../../../os/osinit.c:156
#6 <signal handler called>
#7 0x000055ba9de1c7f6 in present_wnmd_flip (damage=0x55ba9f3a6790, sync_flip=1, pixmap=0x55ba9f2abe40, target_msc=20078, event_id=111509, crtc=0x55ba9fa93960, window=0x55ba9f3a6740) at ../../../../present/present_wnmd.c:359
#8 present_wnmd_execute (vblank=0x55ba9fa98d80, ust=14909996978, crtc_msc=20077) at ../../../../present/present_wnmd.c:465
#9 0x000055ba9de1d395 in present_wnmd_event_notify (window=<optimized out>, event_id=<optimized out>, ust=<optimized out>, msc=***@entry=20077) at ../../../../present/present_wnmd.c:218
#10 0x000055ba9dd5f050 in xwl_present_events_notify (xwl_present_window=***@entry=0x55ba9f3a6c40) at ../../../../../hw/xwayland/xwayland-present.c:199
#11 0x000055ba9dd5f1f3 in xwl_present_timer_callback (timer=<optimized out>, time=<optimized out>, arg=0x55ba9f3a6c40) at ../../../../../hw/xwayland/xwayland-present.c:221
#12 0x000055ba9deae180 in DoTimer (timer=0x55ba9f3891e0, now=***@entry=14909996) at ../../../../os/WaitFor.c:276
#13 0x000055ba9deae1f8 in DoTimers (now=14909996) at ../../../../os/WaitFor.c:290
#14 0x000055ba9deae487 in check_timers () at ../../../../os/WaitFor.c:133
#15 WaitForSomething (are_ready=<optimized out>) at ../../../../os/WaitFor.c:195
#16 0x000055ba9de7e7fc in Dispatch () at ../../../../include/list.h:220
#17 0x000055ba9de829f6 in dix_main (argc=12, argv=0x7ffd8ab2d1b8, envp=<optimized out>) at ../../../../dix/main.c:276
#18 0x00007f1110be5b17 in __libc_start_main (main=0x55ba9dd541b0 <main>, argc=12, argv=0x7ffd8ab2d1b8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffd8ab2d1a8) at ../csu/libc-start.c:310
#19 0x000055ba9dd541ea in _start ()