Bug 371861

Summary: Running kwin_wayland under kwin_wayland without xwayland
Product: [Plasma] kwin Reporter: Kai Uwe Broulik <kde>
Component: wayland-genericAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED WORKSFORME    
Severity: crash Keywords: triaged
Priority: NOR Flags: mgraesslin: Wayland+
Version First Reported In: git master   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description Kai Uwe Broulik 2016-10-30 10:49:09 UTC 
I just tried to run a nested kwin_wayland inside my kwin_wayland session. I did not specify xwayland argument and kwin just crashed on startup.

export $(dbus-launch)
kwin_wayland --windowed --socket wayland-1

(gdb) thread apply all bt

Thread 3 (Thread 0x7fffdeba0700 (LWP 4665)):
#0  0x00007ffff55d0b5d in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007fffede4f39c in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fffede4f4ac in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007ffff611d23b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007ffff60c7cea in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007ffff5eecfb4 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007ffff5ef1b98 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007ffff6e5f70a in start_thread (arg=0x7fffdeba0700) at pthread_create.c:333
#8  0x00007ffff55dc82d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7fffe1771940 (LWP 4660)):
#0  0x00007ffff60c9939 in QCoreApplicationPrivate::sendThroughApplicationEventFilters(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#1  0x00007ffff64758d8 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#2  0x00007ffff647d296 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#3  0x00007ffff60c9cf8 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007ffff60fbef6 in QObjectPrivate::setParent_helper(QObject*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007ffff60fc4b8 in QObject::~QObject() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007ffff7a54488 in KWin::Platform::~Platform() () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#7  0x00007fffdebad374 in KWin::X11WindowedBackend::~X11WindowedBackend() () from /usr/lib/x86_64-linux-gnu/qt5/plugins/org.kde.kwin.waylandbackends/KWinWaylandX11Backend.so
#8  0x00007fffdebad3a4 in KWin::X11WindowedBackend::~X11WindowedBackend() () from /usr/lib/x86_64-linux-gnu/qt5/plugins/org.kde.kwin.waylandbackends/KWinWaylandX11Backend.so
#9  0x00007ffff60bf169 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007ffff60c053b in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#11 0x00007ffff551036a in __cxa_finalize (d=0x7ffff6316920) at cxa_finalize.c:56
#12 0x00007ffff5ec1df3 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#13 0x00007fffffffd6f0 in ?? ()
#14 0x00007ffff7de7c17 in _dl_fini () at dl-fini.c:235
Backtrace stopped: frame did not save the PC
(gdb) 

While I agree that Xwayland is mandatory for kwin_wayland for now, it should abort with "FATAL ERROR: failed to start Xwayland" or what it usually does instead of crashing.
Comment 1 Martin Flöser 2016-10-30 17:21:41 UTC 
Unfortunately the backtrace is lacking debug symbols. In case you are able to reproduce please install debug packages and attach a new backtrace.

Furthermore I need to point out that you used the wrong platform:
> KWin::X11WindowedBackend::~X11WindowedBackend

Means you used the nested X11 platform on a Wayland session. You need to install the Wayland platform for a nested Wayland session on a Wayland session.
Comment 2 Andrew Crouthamel 2018-09-26 22:20:35 UTC 
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information as soon as possible and set the bug status as REPORTED. Due to regular bug tracker maintenance, if the bug is still in NEEDSINFO status with no change in 30 days, the bug will be closed as RESOLVED > WORKSFORME due to lack of needed information.

For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please set the bug status as REPORTED so that the KDE team knows that the bug is ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 3 Andrew Crouthamel 2018-10-27 04:09:34 UTC 
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least 30 days. The bug is now closed as RESOLVED > WORKSFORME due to lack of needed information.

For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

Thank you for helping us make KDE software even better for everyone!