Comment 16 for bug 1783957

one last thing I can give you:

A coredump:

           PID: 1066 (sddm-greeter)
           UID: 118 (sddm)
           GID: 126 (sddm)
        Signal: 11 (SEGV)
     Timestamp: Fri 2018-08-17 10:58:44 EEST (4min 40s ago)
  Command Line: /usr/bin/sddm-greeter --socket /tmp/sddm-:0-OglRQe --theme /usr/share/sddm/themes/breeze
    Executable: /usr/bin/sddm-greeter
 Control Group: /user.slice/user-118.slice/session-1.scope
          Unit: session-1.scope
         Slice: user-118.slice
       Session: 1
     Owner UID: 118 (sddm)
       Boot ID: 581e1a9cb9954ea3a7d3f113c2319d64
    Machine ID: 22374589e49642888b947732702d7902
      Hostname: itlap
       Storage: /var/lib/systemd/coredump/core.sddm-greeter.118.581e1a9cb9954ea3a7d3f113c2319d64.1066.1534492724000000.lz4
       Message: Process 1066 (sddm-greeter) of user 118 dumped core.

                Stack trace of thread 1066:
                #0 0x00007f93fb36d6ce n/a (nouveau_dri.so)
                #1 0x00007f93fb36c1f9 n/a (nouveau_dri.so)
                #2 0x00007f93fb374404 n/a (nouveau_dri.so)
                #3 0x00007f940fd53f88 _ZN16QSGBatchRenderer8Renderer13renderBatchesEv (libQt5Quick.so.5)
                #4 0x00007f940fd5985e _ZN16QSGBatchRenderer8Renderer6renderEv (libQt5Quick.so.5)
                #5 0x00007f940fd4a2a0 _ZN11QSGRenderer11renderSceneERK11QSGBindable (libQt5Quick.so.5)
                #6 0x00007f940fd4a75b _ZN11QSGRenderer11renderSceneEj (libQt5Quick.so.5)
                #7 0x00007f940fd84990 _ZN23QSGDefaultRenderContext15renderNextFrameEP11QSGRendererj (libQt5Quick.so.5)
                #8 0x00007f940fde2a08 _ZN19QQuickWindowPrivate16renderSceneGraphERK5QSize (libQt5Quick.so.5)
                #9 0x00007f940fd76ec9 n/a (libQt5Quick.so.5)
                #10 0x00007f940fd77eaa n/a (libQt5Quick.so.5)
                #11 0x00007f940e53f375 _ZN7QWindow5eventEP6QEvent (libQt5Gui.so.5)
                #12 0x00007f940fdec565 _ZN12QQuickWindow5eventEP6QEvent (libQt5Quick.so.5)
                #13 0x00007f940df7183a _ZN16QCoreApplication6notifyEP7QObjectP6QEvent (libQt5Core.so.5)
                #14 0x00007f940df719a8 _ZN16QCoreApplication15notifyInternal2EP7QObjectP6QEvent (libQt5Core.so.5)
                #15 0x00007f940e53443f _ZN22QGuiApplicationPrivate18processExposeEventEPN29QWindowSystemInterfacePrivate11ExposeEventE (libQt5Gui.so.5)
                #16 0x00007f940e53507d _ZN22QGuiApplicationPrivate24processWindowSystemEventEPN29QWindowSystemInterfacePrivate17WindowSystemEventE (libQt5Gui.so.5)
                #17 0x00007f940e50c2eb _ZN22QWindowSystemInterface22sendWindowSystemEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Gui.so.5)
                #18 0x00007f94066d81c0 n/a (libQt5XcbQpa.so.5)
                #19 0x00007f940a774287 g_main_context_dispatch (libglib-2.0.so.0)
                #20 0x00007f940a7744c0 n/a (libglib-2.0.so.0)
                #21 0x00007f940a77454c g_main_context_iteration (libglib-2.0.so.0)
                #22 0x00007f940dfca8ef _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5)
                #23 0x00007f940df6f9ea _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5)
                #24 0x00007f940df78a84 _ZN16QCoreApplication4execEv (libQt5Core.so.5)
                #25 0x0000563f63e5db79 main (sddm-greeter)
                #26 0x00007f940d371b97 __libc_start_main (libc.so.6)
                #27 0x0000563f63e5dcfa _start (sddm-greeter)

                Stack trace of thread 1069:
                #0 0x00007f940d464bf9 __GI___poll (libc.so.6)
                #1 0x00007f940f9cf747 n/a (libxcb.so.1)
                #2 0x00007f940f9d136a xcb_wait_for_event (libxcb.so.1)
                #3 0x00007f94066752a9 n/a (libQt5XcbQpa.so.5)
                #4 0x00007f940dd9316d n/a (libQt5Core.so.5)
                #5 0x00007f940c02b6db start_thread (libpthread.so.0)
                #6 0x00007f940d47188f __clone (libc.so.6)

                Stack trace of thread 1070:
                #0 0x00007f940c0319f3 futex_wait_cancelable (GNU gdb (Ubuntu 8.1-0ubuntu3) 8.1.0.20180409-git
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
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For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from /usr/bin/sddm-greeter...(no debugging symbols found)...done.
[New LWP 1066]
[New LWP 1069]
[New LWP 1070]
[New LWP 1071]
[New LWP 1076]
[New LWP 1125]
[New LWP 1126]
[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/sddm-greeter --socket /tmp/sddm-:0-OglRQe --theme /usr/share/sddm/them'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x00007f93fb36d6ce in ?? () from /usr/lib/x86_64-linux-gnu/dri/nouveau_dri.so
[Current thread is 1 (Thread 0x7f9410417800 (LWP 1066))]
(gdb) (gdb) quit
libpthread.so.0)
                #1 0x00007f93fb46d46b n/a (nouveau_dri.so)
                #2 0x00007f93fb46d197 n/a (nouveau_dri.so)
                #3 0x00007f940c02b6db start_thread (libpthread.so.0)
                #4 0x00007f940d47188f __clone (libc.so.6)

                Stack trace of thread 1071:
                #0 0x00007f940d464bf9 __GI___poll (libc.so.6)
                #1 0x00007f940a774439 n/a (libglib-2.0.so.0)
                #2 0x00007f940a77454c g_main_context_iteration (libglib-2.0.so.0)
                #3 0x00007f940dfca8ef _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5)
                #4 0x00007f940df6f9ea _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5)
                #5 0x00007f940dd8e22a _ZN7QThread4execEv (libQt5Core.so.5)
                #6 0x00007f940f2076f5 n/a (libQt5Qml.so.5)
                #7 0x00007f940dd9316d n/a (libQt5Core.so.5)
                #8 0x00007f940c02b6db start_thread (libpthread.so.0)
                #9 0x00007f940d47188f __clone (libc.so.6)

                Stack trace of thread 1076:
                #0 0x00007f940d464bf9 __GI___poll (libc.so.6)
                #1 0x00007f940a774439 n/a (libglib-2.0.so.0)
                #2 0x00007f940a77454c g_main_context_iteration (libglib-2.0.so.0)
                #3 0x00007f940dfca8ef _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5)
                #4 0x00007f940df6f9ea _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5)
                #5 0x00007f940dd8e22a _ZN7QThread4execEv (libQt5Core.so.5)
                #6 0x00007f9406181d45 n/a (libQt5DBus.so.5)
                #7 0x00007f940dd9316d n/a (libQt5Core.so.5)
                #8 0x00007f940c02b6db start_thread (libpthread.so.0)
                #9 0x00007f940d47188f __clone (libc.so.6)

                Stack trace of thread 1125:
                #0 0x00007f940c0319f3 futex_wait_cancelable (libpthread.so.0)
                #1 0x00007f940dd9459b _ZN14QWaitCondition4waitEP6QMutexm (libQt5Core.so.5)
                #2 0x00007f940dd8cc0b _ZN10QSemaphore7acquireEi (libQt5Core.so.5)
                #3 0x00007f9401d9375b n/a (libqtvirtualkeyboardplugin.so)
                #4 0x00007f940dd9316d n/a (libQt5Core.so.5)
                #5 0x00007f940c02b6db start_thread (libpthread.so.0)
                #6 0x00007f940d47188f __clone (libc.so.6)

                Stack trace of thread 1126:
                #0 0x00007f940c0319f3 futex_wait_cancelable (libpthread.so.0)
                #1 0x00007f940dd9459b _ZN14QWaitCondition4waitEP6QMutexm (libQt5Core.so.5)
                #2 0x00007f93da29ea3f n/a (libqmlfolderlistmodelplugin.so)
                #3 0x00007f940dd9316d n/a (libQt5Core.so.5)
                #4 0x00007f940c02b6db start_thread (libpthread.so.0)
                #5 0x00007f940d47188f __clone (libc.so.6)