Bug 784041

Summary: plasma-desktop crashes with segmentation fault (signal 11) when changing virtual desktops
Product: [Fedora] Fedora Reporter: John Florian <john>
Component: kdebase-workspaceAssignee: Than Ngo <than>
Status: CLOSED DUPLICATE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 16CC: fedora, jbastian, jreznik, kevin, ltinkl, rdieter, rnovacek, ry, smparrish, than
Target Milestone: ---   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2012-02-11 17:02:15 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:

Description John Florian 2012-01-23 16:24:11 UTC 
Description of problem:
I frequently see plasma-desktop crash (and restart itself) when changing virtual desktops via custom shortcut keys Ctrl+Alt+0 through Ctrl+Alt+9 (ten virtual desktops).

Version-Release number of selected component (if applicable):
kdebase-workspace-4.7.4-6.fc16.x86_64

How reproducible:
About 10% of the time.  It seems more likely to happen if I'm working along normally and occasionally need to change desktops than if I just sit there and hit my shortcut keys repeatedly in an attempt to induce the problem.

Steps to Reproduce:
1. Configure the workspace to provide multiple virtual desktops.
2. Configure shortcut keys to switch between them.
3. Work for a while in one desktop and then switch to another using shortcut keys.
  
Actual results:
About 10% of the time, the Plasma Desktop Shell - The KDE Crash Handler dialog appears saying the executable plasma-desktop PID: NNNN Signal: Segmentation fault(11).

Expected results:
Shouldn't crash, of course.

Additional info:
My colleagues are using the same Fedora release on identical hardware and do not see this problem, ever.  I can reproduce it between both my work computers and home computers, which are not identical hardware configs.  The primary difference I see between my use (failing) and theirs (working) is my shortcut combinations.

I have also seen it when I choose to change window focus with a Ctrl+Left-Button on the desktop which I have configured the Desktop Settings for Mouse Actions with Ctrl+Left-Button == Switch Window (Display all windows in one list).  In this case, presenting the menu is okay, but selecting one of the windows can induce the bug.
Comment 1 Jeff Bastian 2012-02-10 19:38:44 UTC 
It's been crashing for me also.  I installed the debuginfo packages this morning and just caught a backtrace:

Application: Plasma Desktop Shell (plasma-desktop), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
82	T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
[Current thread is 1 (Thread 0x7f5166314840 (LWP 2191))]

Thread 2 (Thread 0x7f51511a6700 (LWP 2192)):
#0  0x000000359fce6af3 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x0000003c08444fd8 in g_main_context_poll (n_fds=1, fds=0x7f514c002400, priority=<optimized out>, timeout=-1, context=0x7f514c0009a0) at gmain.c:3402
#2  g_main_context_iterate (context=0x7f514c0009a0, block=<optimized out>, dispatch=1, self=<optimized out>) at gmain.c:3084
#3  0x0000003c0844549c in g_main_context_iteration (context=0x7f514c0009a0, may_block=1) at gmain.c:3152
#4  0x0000003c0a9a7dc6 in QEventDispatcherGlib::processEvents (this=0x7f514c0008c0, flags=<optimized out>) at kernel/qeventdispatcher_glib.cpp:426
#5  0x0000003c0a978182 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#6  0x0000003c0a9783d7 in QEventLoop::exec (this=0x7f51511a5d10, flags=...) at kernel/qeventloop.cpp:204
#7  0x0000003c0a878b27 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#8  0x0000003c0a957e7f in QInotifyFileSystemWatcherEngine::run (this=0x29266d0) at io/qfilesystemwatcher_inotify.cpp:248
#9  0x0000003c0a87bb6b in QThreadPrivate::start (arg=0x29266d0) at thread/qthread_unix.cpp:298
#10 0x00000035a0807d90 in start_thread (arg=0x7f51511a6700) at pthread_create.c:309
#11 0x000000359fcef48d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:115

Thread 1 (Thread 0x7f5166314840 (LWP 2191)):
[KCrash Handler]
#6  KWindowInfo::valid (this=0x4d0010, withdrawn_is_valid=true) at /usr/src/debug/kdelibs-4.7.4/kdeui/windowmanagement/kwindowinfo_x11.cpp:133
#7  0x0000003169632ad6 in TaskManager::Task::isOnCurrentDesktop (this=0x2a228f0) at /usr/src/debug/kde-workspace-4.7.4/libs/taskmanager/task.cpp:211
#8  0x00007f5148852d44 in TaskSource::updateDesktop (this=0x2887730, desktop=<optimized out>) at /usr/src/debug/kde-workspace-4.7.4/plasma/generic/dataengines/tasks/tasksource.cpp:161
#9  0x00007f514885307b in TaskSource::qt_static_metacall (_o=<optimized out>, _c=<optimized out>, _id=<optimized out>, _a=<optimized out>) at /usr/src/debug/kde-workspace-4.7.4/x86_64-redhat-linux-gnu/plasma/generic/dataengines/tasks/tasksource.moc:57
#10 0x0000003c0a98cce1 in QMetaObject::activate (sender=0x2775a80, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fffe6ffaf50) at kernel/qobject.cpp:3547
#11 0x000000316963ec61 in TaskManager::TaskManager::desktopChanged (this=<optimized out>, _t1=1) at /usr/src/debug/kde-workspace-4.7.4/x86_64-redhat-linux-gnu/libs/taskmanager/taskmanager.moc:214
#12 0x0000003169640843 in qt_static_metacall (_a=<optimized out>, _id=<optimized out>, _o=<optimized out>, _c=<optimized out>) at /usr/src/debug/kde-workspace-4.7.4/x86_64-redhat-linux-gnu/libs/taskmanager/taskmanager.moc:104
#13 TaskManager::TaskManager::qt_static_metacall (_o=<optimized out>, _c=<optimized out>, _id=<optimized out>, _a=<optimized out>) at /usr/src/debug/kde-workspace-4.7.4/x86_64-redhat-linux-gnu/libs/taskmanager/taskmanager.moc:87
#14 0x0000003c0a98cce1 in QMetaObject::activate (sender=0x223d4b0, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fffe6ffb180) at kernel/qobject.cpp:3547
#15 0x0000003c0f98662e in KWindowSystem::currentDesktopChanged (this=<optimized out>, _t1=1) at /usr/src/debug/kdelibs-4.7.4/x86_64-redhat-linux-gnu/kdeui/kwindowsystem.moc:136
#16 0x0000003c0f988ca3 in KWindowSystemPrivate::x11Event (this=0x228fbd0, ev=0x7fffe6ffb290) at /usr/src/debug/kdelibs-4.7.4/kdeui/windowmanagement/kwindowsystem_x11.cpp:175
#17 0x0000003c0f87a116 in publicX11Event (e=0x7fffe6ffb290, this=<optimized out>) at /usr/src/debug/kdelibs-4.7.4/kdeui/kernel/ksystemeventfilter.cpp:43
#18 KSystemEventFilterPrivate::filterEvent (this=0x230f620, message=0x7fffe6ffb290) at /usr/src/debug/kdelibs-4.7.4/kdeui/kernel/ksystemeventfilter.cpp:102
#19 0x0000003c0bc6c966 in x11EventSourceDispatch (s=0x21751b0, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:145
#20 0x0000003c08444acd in g_main_dispatch (context=0x2174c00) at gmain.c:2441
#21 g_main_context_dispatch (context=0x2174c00) at gmain.c:3011
#22 0x0000003c084452c8 in g_main_context_iterate (context=0x2174c00, block=<optimized out>, dispatch=1, self=<optimized out>) at gmain.c:3089
#23 0x0000003c0844549c in g_main_context_iteration (context=0x2174c00, may_block=1) at gmain.c:3152
#24 0x0000003c0a9a7d5f in QEventDispatcherGlib::processEvents (this=0x216f6c0, flags=<optimized out>) at kernel/qeventdispatcher_glib.cpp:424
#25 0x0000003c0bc6c66e in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=<optimized out>) at kernel/qguieventdispatcher_glib.cpp:207
#26 0x0000003c0a978182 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#27 0x0000003c0a9783d7 in QEventLoop::exec (this=0x7fffe6ffb660, flags=...) at kernel/qeventloop.cpp:204
#28 0x0000003c0a97cdd5 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1148
#29 0x0000003169241243 in kdemain (argc=1, argv=0x7fffe6ffba48) at /usr/src/debug/kde-workspace-4.7.4/plasma/desktop/shell/main.cpp:120
#30 0x000000359fc2169d in __libc_start_main (main=0x400850 <main(int, char**)>, argc=1, ubp_av=0x7fffe6ffba48, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffe6ffba38) at libc-start.c:226
#31 0x0000000000400881 in _start ()
Comment 2 John Florian 2012-02-10 20:28:05 UTC 
Awesome Jeff, thanks for that.  Between the mandatory corporate proxy and SELinux policy (I think), I've had no luck in getting a backtrace.
Comment 3 Rex Dieter 2012-02-11 17:02:15 UTC 

*** This bug has been marked as a duplicate of bug 789598 ***