[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[bugzilla_noreply]

https://bugs.kde.org/show_bug.cgi?id=393804

tagwer...@innerjoin.org changed:

   What|Removed |Added

 CC||tagwer...@innerjoin.org

--- Comment #12 from tagwer...@innerjoin.org ---
(In reply to Adam Ruckel from comment #10)
> ... I can confirm this is still an issue on the following systems that I used 
> in
> last 3 months ...
> 
> 5.20 (Fedora 33)
If the main symptom is "freezing when pasting" (when trying to copy between
VM's), then
https://bugs.kde.org/show_bug.cgi?id=417590#c19
seems related. I do still encounter this.

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[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[bugzilla_noreply]

https://bugs.kde.org/show_bug.cgi?id=393804

landgraf...@yandex.ru changed:

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 CC||landgraf...@yandex.ru

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[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[Nate Graham]

https://bugs.kde.org/show_bug.cgi?id=393804

Nate Graham  changed:

   What|Removed |Added

  Component|general |Clipboard
   Assignee|k...@davidedmundson.co.uk|plasma-b...@kde.org
 Status|REOPENED|CONFIRMED

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[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[bugzilla_noreply]

https://bugs.kde.org/show_bug.cgi?id=393804

valdi...@gmail.com changed:

   What|Removed |Added

 CC||valdi...@gmail.com

--- Comment #11 from valdi...@gmail.com ---
I can confirm this issue. It also happens with other two-way-clipboard-sync
applications like VirtualBox or FreeRDP.

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[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[Adam Ruckel]

https://bugs.kde.org/show_bug.cgi?id=393804

Adam Ruckel  changed:

   What|Removed |Added

 Resolution|UPSTREAM|---
 Status|RESOLVED|REOPENED

--- Comment #10 from Adam Ruckel  ---
Please don’t take it offensive but this bug should not be closed. I understand
that this is a Qt issue but I’m a user, not a developer. If I open a bug in Qt
bugzilla, I don’t know what to tell them. But I do know how to explain it here
- from a perspective of a user.

I can confirm this is still an issue on the following systems that I used in
last 3 months:

5.14 (Debian)
5.18 (Kubuntu 20.04)
5.19 (Kubuntu 20.10)
5.20 (Fedora 33)
5.21 (Arch)

Workaround:

Configure System Tray => Disable Clipboard.

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[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[Nate Graham]

https://bugs.kde.org/show_bug.cgi?id=393804

Nate Graham  changed:

   What|Removed |Added

 Resolution|--- |UPSTREAM
 CC||n...@kde.org
URL||https://bugreports.qt.io/br
   ||owse/QTBUG-67822
 Status|CONFIRMED   |RESOLVED

--- Comment #9 from Nate Graham  ---
Seems like this issue is fully upstream in Qt. I would recommend following up
there. Thanks for the thorough investigation, everyone!

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[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[Aleix Pol]

https://bugs.kde.org/show_bug.cgi?id=393804

--- Comment #8 from Aleix Pol  ---
I've looked into it, it looks like an issue in QXcbClipboard, which obviously
doesn't help but we better say so.

It seems quite similar to this bug report here in Qt Creator (funny that Qt
Creator people talk about Qt as upstream as well).
https://bugreports.qt.io/browse/QTBUG-67822?jql=text%20~%20%22waitForClipboardEvent%22

It could make sense to try and simplify the test case.
Or just try to make sense of qxcbclipboard.cpp.

What we have here is QXcbClipboard::getSelection blocking on
QXcbClipboard::waitForClipboardEvent to get the requested selection. There's
supposedly a 5s timeout which doesn't seem to arrive either.

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[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[Aleix Pol]

https://bugs.kde.org/show_bug.cgi?id=393804

Aleix Pol  changed:

   What|Removed |Added

 Status|REPORTED|CONFIRMED
 Ever confirmed|0   |1
 CC||aleix...@kde.org

--- Comment #7 from Aleix Pol  ---
I've looked into it, it looks like an issue in QXcbClipboard, which obviously
doesn't help but we better say so.

It seems quite similar to this bug report here in Qt Creator (funny that Qt
Creator people talk about Qt as upstream as well).
https://bugreports.qt.io/browse/QTBUG-67822?jql=text%20~%20%22waitForClipboardEvent%22

It could make sense to try and simplify the test case.
Or just try to make sense of qxcbclipboard.cpp.

What we have here is QXcbClipboard::getSelection blocking on
QXcbClipboard::waitForClipboardEvent to get the requested selection. There's
supposedly a 5s timeout which doesn't seem to arrive either.

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[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[Christoph Feck]

https://bugs.kde.org/show_bug.cgi?id=393804

--- Comment #6 from Christoph Feck  ---
If developers need more information, they will come back to you. If we find a
developer able to fix this issue, then the bug status is automatically updated.

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[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[Adam Ruckel]

https://bugs.kde.org/show_bug.cgi?id=393804

--- Comment #5 from Adam Ruckel  ---
This is my first bug on KDE.org so I'm not sure what to do now. Do you want me
to change status to CONFIRMED? Or is there anything else I can do to help?

Thank you

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[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[Adam Ruckel]

https://bugs.kde.org/show_bug.cgi?id=393804

Adam Ruckel  changed:

   What|Removed |Added

 CC||ad.ruc...@gmail.com

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[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[Adam Ruckel]

https://bugs.kde.org/show_bug.cgi?id=393804

--- Comment #4 from Adam Ruckel  ---
I agree with @Harald and I need to add that the guest does NOT have to be
Plasma. Single guest with Windows (and with updated Spice / Virtio drivers) is
also a problem.

I tested to connect this Windows box remotely over SSH from old Plasma (no
problems) and locally / remotely from the current Plasma (clip freezing issue).

Btw. I don't think that we're on Wayland so this must be some strange Host
issue.

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[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[Harald Sitter]

https://bugs.kde.org/show_bug.cgi?id=393804

Harald Sitter  changed:

   What|Removed |Added

 CC||sit...@kde.org

--- Comment #3 from Harald Sitter  ---
I can reproduce this on neon with Plasma 5.12.5 (+ Qt 5.10 + Ubuntu 16.04 base)
for the host and Plasma master (+ Qt 5.10 + Ubuntu 18.04 base) as guest in the
VM.

A couple of observations:

Doesn't happen if you disable clipboard sync (e.g. `virt-xml neonUnstableBionic
--update --edit --graphics
spice,listen=127.0.0.1,port=5900,clipboard_copypaste=no`)

The freeze also doesn't happen when you leave clipboard sync enabled but
disable the host klipper (e.g. remove the systray applet). Kinda expected but I
thought I'd point it out. To the same end disabling the guest klipper does the
same, albeit even more obvious since it freezes in the code you'd disable xD. 

Disabling the `newClipData`/`slotCheckPending` function of klipper on the host
also seems to prevent the freeze, not sure what that tells us other than the
host doing something which then prompts the freeze in the guest.

The guest Plasma doesn't always freeze, sometimes it doesn't for a dozen
copies, sometimes it does after only a couple. What then seems to happen is it
hitting a timeout as after numerous seconds it will unfreeze again.

For my host the plasma never freezes, it does however sometimes seem to "lose"
a paste. Say I am in konsole, copy something, then go to firefox and paste it,
nothing pastes and the klipper history has an empty entry. I am not entirely
sure this is related, but it certainly seems to only happen when I also have a
Plasma VM running.

The last two points particularly make me think that this is maybe a race
condition between the two klippers. Why one freezes and the other doesn't is
somewhat beyond me though. Might also be a loop between the two, but then I'd
expect more consistent freezing on both ends.

Backtrace of the Guest Plasma (the frozen one).

Thread 10 (Thread 0x7f80ad06b700 (LWP 4875)):
#0  0x7f8191320ed9 in futex_reltimed_wait_cancelable (private=, reltime=0x7f80ad06ac00, expected=0, 
futex_word=0x55c4889fc5a0) at
../sysdeps/unix/sysv/linux/futex-internal.h:142
#1  __pthread_cond_wait_common (abstime=0x7f80ad06acc0, mutex=0x55c4889fc550,
cond=0x55c4889fc578) at pthread_cond_wait.c:533
#2  __pthread_cond_timedwait (cond=0x55c4889fc578, mutex=0x55c4889fc550,
abstime=0x7f80ad06acc0) at pthread_cond_wait.c:667
#3  0x7f81921a2eb8 in QWaitConditionPrivate::wait_relative (time=3,
this=0x55c4889fc550) at thread/qwaitcondition_unix.cpp:133
#4  QWaitConditionPrivate::wait (time=3, this=0x55c4889fc550) at
thread/qwaitcondition_unix.cpp:141
#5  QWaitCondition::wait (this=this@entry=0x55c48864d140,
mutex=mutex@entry=0x55c48863ceb0, time=3) at
thread/qwaitcondition_unix.cpp:215
#6  0x7f819219eefd in QThreadPoolThread::run (this=0x55c48864d130) at
thread/qthreadpool.cpp:146
#7  0x7f81921a1b8f in QThreadPrivate::start (arg=0x55c48864d130) at
thread/qthread_unix.cpp:376
#8  0x7f819131a6db in start_thread (arg=0x7f80ad06b700) at
pthread_create.c:463
#9  0x7f8191a9488f in clone () at
../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 9 (Thread 0x7f80c0d2c700 (LWP 4857)):
#0  0x7f8191a87bf9 in __GI___poll (fds=0x7f80bc006470, nfds=1,
timeout=3500478) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x7f818b8b0439 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x7f818b8b054c in g_main_context_iteration () from
/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x7f81923e2c9f in QEventDispatcherGlib::processEvents
(this=0x7f80bc000b20, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#4  0x7f819238673a in QEventLoop::exec (this=this@entry=0x7f80c0d2bd20,
flags=..., flags@entry=...) at kernel/qeventloop.cpp:212
#5  0x7f819219c82a in QThread::exec (this=) at
thread/qthread.cpp:522
#6  0x7f80c368a067 in KCupsConnection::run() () from
/usr/lib/x86_64-linux-gnu/libkcupslib.so
#7  0x7f81921a1b8f in QThreadPrivate::start (arg=0x55c4871a6930) at
thread/qthread_unix.cpp:376
#8  0x7f819131a6db in start_thread (arg=0x7f80c0d2c700) at
pthread_create.c:463
#9  0x7f8191a9488f in clone () at
../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 8 (Thread 0x7f80d689f700 (LWP 4847)):
#0  0x7f8191a87bf9 in __GI___poll (fds=0x7f80d0005220, nfds=1, timeout=-1)
at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x7f818b8b0439 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x7f818b8b054c in g_main_context_iteration () from
/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x7f81923e2c9f in QEventDispatcherGlib::processEvents
(this=0x7f80db20, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#4  0x7f819238673a in QEventLoop::exec (this=this@entry=0x7f80d689ecf0,
flags=..., flags@entry=...) at 

[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[Peter Eszlari]

https://bugs.kde.org/show_bug.cgi?id=393804

Peter Eszlari  changed:

   What|Removed |Added

 CC||peter.eszl...@gmail.com

--- Comment #2 from Peter Eszlari  ---
I'm seeing this bug too - running Ubuntu 18.04 in virt-manager on Kubuntu
18.04.

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[plasmashell] [Bug 393804] Clipboard freezes when KVM/QEMU VM window is opened using virt-manager

[Adam Ruckel]

https://bugs.kde.org/show_bug.cgi?id=393804

--- Comment #1 from Adam Ruckel  ---
"plasmashell --version" command on Debian gets:
plasmashell 5.8.6

and on Fedora:
plasmashell 5.10.1

so the bug was introduced probably in 5.10.[6-9]. I'm not sure about 5.10.5
since "rpm -qa" gets "5.10.5" on Fedora

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