https://bugs.kde.org/show_bug.cgi?id=446581
Bug ID: 446581
Summary: plasmashell and Firefox hang when Firefox attempts to
update the clipboard and show a notification at the
same time
Product: plasmashell
Version: 5.23.4
Platform: Other
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: Notifications
Assignee: k...@privat.broulik.de
Reporter: nyanpas...@tuta.io
CC: plasma-b...@kde.org
Target Milestone: 1.0
SUMMARY
On KDE Plasma X11, with Klipper (clipboard history) added to plasmashell, and
Firefox with "Copy Selected Tabs to Clipboard" installed, trying to use the
extension often causes Firefox and plasmashell (and any app trying to paste) to
deadlock and hang.
STEPS TO REPRODUCE
1. Install Firefox and
https://addons.mozilla.org/en-US/firefox/addon/copy-selected-tabs-to-clipboar/.
2. Add the Clipboard applet to a plasmashell panel. (Unsure if necessary, my
System Tray applet also has a clipboard icon! I'm not sure how to show/hide
it.)
3. With Plasma X11 running (doesn't happen on Wayland), right-click a Firefox
tab, expand the "Copy to Clipboard" menu, and click "URL".
OBSERVED RESULT
Around 50% of the time, Firefox and plasmashell (and any app I try pasting
into) hang for 10 seconds. Afterwards, plasmashell gives up trying to grab
clipboard contents, the notification gets shown, and the clipboard is updated
but Klipper is missing the clipboard entry.
EXPECTED RESULT
The notification gets shown, the clipboard is updated, and Klipper contains the
new entry.
SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.23.4
KDE Frameworks Version: 5.88.0
Qt Version: 5.15.2
Kernel Version: 5.15.4-zen1-1-zen (64-bit)
Graphics Platform: X11
Processors: 12 × AMD Ryzen 5 5600X 6-Core Processor
Memory: 15.6 GiB of RAM
Graphics Processor: NVIDIA GeForce GT 730/PCIe/SSE2
Firefox 94.0.2 (64-bit)
Copy Selected Tabs to Clipboard: 1.4.3
ADDITIONAL INFORMATION
When you use the extension to copy a tab list, Firefox sends a "clipboard
changed" event (through X11 I assume, not sure) and attempts to send a
notification through D-Bus (`notify_notification_show () at
/usr/lib/libnotify.so.4` blocks on
`g_dbus_connection_send_message_with_reply_sync`).
Meanwhile plasmashell can't process the notification and unblock Firefox,
because the Klipper plasmashell plugin is blocked trying to grab the clipboard
contents (`QMimeData::text()` blocks on `QXcbClipboard::getSelection` and
`QXcbClipboard::waitForClipboardEvent`). IDK exactly how X11 clipboards work,
but I assume plasmashell/Klipper asks Xorg to ask Firefox for clipboard
contents. But Firefox can't provide clipboard contents until it's done showing
a notification, and plasmashell won't show the notification until it gets the
clipboard contents.
And both apps lock up for 10 seconds (I think plasmashell takes two 5-second
timeouts to give up). And in the end, plasmashell gives up trying to grab
clipboard contents, processes the notification, and both programs get unblocked
(but Klipper is missing the clipboard entry).
Which app is at fault and should be fixed? Firefox? plasmashell? "Copy Selected
Tabs to Clipboard"? Klipper?
Firefox backtrace during hang (recorded a few months ago):
(gdb) bt
#0 0x00007f8086af6b2f in poll () at /usr/lib/libc.so.6
#1 0x00007f808549d819 in g_main_context_poll (priority=<optimized out>,
n_fds=1, fds=0x7f80412e7488, timeout=<optimized out>, context=0x7f8032c6a190)
at ../glib/glib/gmain.c:4478
#2 g_main_context_iterate.constprop.0 (context=0x7f8032c6a190,
block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at
../glib/glib/gmain.c:4170
#3 0x00007f8085447663 in g_main_loop_run (loop=0x7f803989b4a0) at
../glib/glib/gmain.c:4373
#4 0x00007f8085324a14 in g_dbus_connection_send_message_with_reply_sync
(connection=0x7f8086769d00, message=0x7f802610f470,
flags=G_DBUS_SEND_MESSAGE_FLAGS_NONE, timeout_msec=-1, out_serial=0x0,
cancellable=0x0, error=0x7fff9df3cd40) at ../glib/gio/gdbusconnection.c:2179
#5 0x00007f808533276d in g_dbus_connection_call_sync_internal
(connection=0x7f8086769d00, bus_name=0x7f803989b3d0 ":1.36749",
object_path=0x7f8038014740 "/org/freedesktop/Notifications",
interface_name=0x7f80380144e0 "org.freedesktop.Notifications",
method_name=0x7f8045e7d24b "Notify", parameters=0x7f803a81eca0,
reply_type=0x7f808538d99c, flags=G_DBUS_CALL_FLAGS_NONE, timeout_msec=-1,
fd_list=0x0, out_fd_list=0x0, cancellable=0x0, error=0x7fff9df3d088) at
../glib/gio/gdbusconnection.c:6121
#6 0x00007f808533ba77 in g_dbus_proxy_call_sync_internal
(proxy=0x7f803804e650, method_name=<optimized out>, parameters=0x7f803a81eca0,
flags=G_DBUS_CALL_FLAGS_NONE, timeout_msec=<optimized out>,
fd_list=fd_list@entry=0x0, out_fd_list=0x0, cancellable=0x0,
error=0x7fff9df3d088) at ../glib/gio/gdbusproxy.c:2845
#7 0x00007f808533bc48 in g_dbus_proxy_call_sync (proxy=<optimized out>,
method_name=<optimized out>, parameters=<optimized out>, flags=<optimized out>,
timeout_msec=<optimized out>, cancellable=<optimized out>,
error=0x7fff9df3d088) at ../glib/gio/gdbusproxy.c:3037
#8 0x00007f8045e7b75d in notify_notification_show () at
/usr/lib/libnotify.so.4
#9 0x00007f807ff40a11 in () at /usr/lib/firefox/libxul.so
...
#30 0x000055aafdb4ebdd in ()
#31 0x00007f8086a2ab25 in __libc_start_main () at /usr/lib/libc.so.6
#32 0x000055aafdbca4ae in _start ()
plasmashell backtrace during hang:
(gdb) bt
#0 0x00007ffff49e28ca in __futex_abstimed_wait_common64 () at
/usr/lib/libpthread.so.0
#1 0x00007ffff49dc574 in pthread_cond_timedwait@@GLIBC_2.3.2 () at
/usr/lib/libpthread.so.0
#2 0x00007ffff5a4e9a4 in QWaitConditionPrivate::wait_relative(QDeadlineTimer)
(deadline=..., this=0x555555650de0) at thread/qwaitcondition_unix.cpp:136
#3 QWaitConditionPrivate::wait(QDeadlineTimer) (deadline=..., deadline=...,
this=0x555555650de0) at thread/qwaitcondition_unix.cpp:144
#4 QWaitCondition::wait(QMutex*, QDeadlineTimer) (this=<optimized out>,
mutex=0x5555556332f8, deadline=...) at thread/qwaitcondition_unix.cpp:225
#5 0x00007ffff5a4eabd in QWaitCondition::wait(QMutex*, unsigned long)
(this=0x555555633300, mutex=0x5555556332f8, time=<optimized out>) at
thread/qwaitcondition_unix.cpp:209
#6 0x00007ffff0960906 in QXcbEventQueue::waitForNewEvents(QXcbEventNode
const*, unsigned long) (this=this@entry=0x555555633290,
sinceFlushedTail=sinceFlushedTail@entry=0x7ffff0a45ed8
<QXcbEventQueue::qXcbEventNodeFactory(xcb_generic_event_t*)::qXcbNodePool+24>,
time=3417) at qxcbeventqueue.cpp:362
#7 0x00007ffff09348f4 in QXcbClipboard::waitForClipboardEvent(unsigned int,
int, bool) (this=this@entry=0x7fffec0047a0, window=window@entry=90177613,
type=type@entry=31, checkManager=checkManager@entry=false) at
qxcbclipboard.cpp:815
#8 0x00007ffff0934ff0 in QXcbClipboard::getSelection(unsigned int, unsigned
int, unsigned int, unsigned int) (this=0x7fffec0047a0, selection=326,
target=target@entry=590, property=333, time=194042584, time@entry=0) at
qxcbclipboard.cpp:906
#9 0x00007ffff0937132 in QXcbClipboard::getDataInFormat(unsigned int, unsigned
int) (fmtAtom=590, modeAtom=<optimized out>, this=<optimized out>) at
qxcbclipboard.cpp:891
#10 QXcbClipboardMime::retrieveData_sys(QString const&, QVariant::Type) const
(this=<optimized out>, fmt=..., type=<optimized out>) at qxcbclipboard.cpp:147
#11 0x00007ffff60396b8 in QInternalMimeData::retrieveData(QString const&,
QVariant::Type) const (this=0x5555563594b0, mimeType=...,
type=QVariant::String) at kernel/qinternalmimedata.cpp:113
#12 0x00007ffff5c635e0 in QMimeDataPrivate::retrieveTypedData(QString const&,
QMetaType::Type) const (this=0x555555cd36a0, format=...,
type=QMetaType::QString) at kernel/qmimedata.cpp:119
#13 0x00007ffff5c64281 in QMimeData::text() const (this=<optimized out>) at
kernel/qmimedata.cpp:409
#14 0x00007fffc809ea4b in HistoryItem::create(QMimeData const*) () at
/usr/lib/qt/plugins/plasma/dataengine/plasma_engine_clipboard.so
#15 0x00007fffc80899be in Klipper::applyClipChanges(QMimeData const*) () at
/usr/lib/qt/plugins/plasma/dataengine/plasma_engine_clipboard.so
#16 0x00007fffc808bf51 in Klipper::checkClipData(bool) () at
/usr/lib/qt/plugins/plasma/dataengine/plasma_engine_clipboard.so
#17 0x00007ffff5c73915 in QtPrivate::QSlotObjectBase::call(QObject*, void**)
(a=0x7fffffffdb70, r=<optimized out>, this=0x7fffec00b4c0) at
../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#18 doActivate<false>(QObject*, int, void**) (sender=0x7fffec008410,
signal_index=3, argv=0x7fffffffdb70) at kernel/qobject.cpp:3886
#19 0x00007fffc80b2363 in SystemClipboard::changed(QClipboard::Mode) () at
/usr/lib/qt/plugins/plasma/dataengine/plasma_engine_clipboard.so
#20 0x00007ffff5c73915 in QtPrivate::QSlotObjectBase::call(QObject*, void**)
(a=0x7fffffffdc80, r=<optimized out>, this=0x555556815b00) at
../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#21 doActivate<false>(QObject*, int, void**) (sender=0x555555e685f0,
signal_index=3, argv=0x7fffffffdc80) at kernel/qobject.cpp:3886
#22 0x00007ffff5c6cee7 in QMetaObject::activate(QObject*, QMetaObject const*,
int, void**) (sender=<optimized out>, m=m@entry=0x7ffff65b1a00
<QClipboard::staticMetaObject>, local_signal_index=local_signal_index@entry=0,
argv=argv@entry=0x7fffffffdc80) at kernel/qobject.cpp:3946
#23 0x00007ffff649ed63 in QClipboard::changed(QClipboard::Mode)
(this=<optimized out>, _t1=<optimized out>) at .moc/moc_qclipboard.cpp:168
#24 0x00007ffff6029670 in QClipboard::emitChanged(QClipboard::Mode)
(this=<optimized out>, mode=<optimized out>) at kernel/qclipboard.cpp:608
#25 0x00007ffff600a4fd in QPlatformClipboard::emitChanged(QClipboard::Mode)
(this=<optimized out>, mode=<optimized out>) at
kernel/qplatformclipboard.cpp:125
#26 0x00007ffff093525f in
QXcbClipboard::handleXFixesSelectionRequest(xcb_xfixes_selection_notify_event_t*)
(this=<optimized out>, event=event@entry=0x7fffec00c660) at
qxcbclipboard.cpp:679
#27 0x00007ffff0938d56 in QXcbConnection::handleXcbEvent(xcb_generic_event_t*)
(this=this@entry=0x55555563f620, event=event@entry=0x7fffec00c660) at
qxcbconnection.cpp:685
#28 0x00007ffff093a2d1 in
QXcbConnection::processXcbEvents(QFlags<QEventLoop::ProcessEventsFlag>)
(this=0x55555563f620, flags=...) at qxcbconnection.cpp:1014
#29 0x00007ffff09617f8 in xcbSourceDispatch(GSource*, GSourceFunc, gpointer)
(source=<optimized out>) at qxcbeventdispatcher.cpp:103
#30 0x00007ffff3f090ec in g_main_dispatch (context=0x7fffec005000) at
../glib/glib/gmain.c:3381
#31 g_main_context_dispatch (context=0x7fffec005000) at
../glib/glib/gmain.c:4099
#32 0x00007ffff3f5e889 in g_main_context_iterate.constprop.0
(context=context@entry=0x7fffec005000, block=block@entry=1,
dispatch=dispatch@entry=1, self=<optimized out>) at ../glib/glib/gmain.c:4175
#33 0x00007ffff3f06735 in g_main_context_iteration (context=0x7fffec005000,
may_block=1) at ../glib/glib/gmain.c:4240
#34 0x00007ffff5c95b2a in
QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>)
(this=0x5555556ea750, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#35 0x00007ffff5c3aabb in
QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>)
(this=this@entry=0x7fffffffdf40, flags=..., flags@entry=...) at
../../include/QtCore/../../src/corelib/global/qflags.h:69
#36 0x00007ffff5c432a8 in QCoreApplication::exec() () at
../../include/QtCore/../../src/corelib/global/qflags.h:121
#37 0x0000555555573136 in main ()
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