Bug 488023

Summary:	plasmashell sometimes crashed in SystemClipboard::checkClipData after copying and pasting files in nautilus
Product:	[Plasma] plasmashell	Reporter:	Matt Fagnani <matt.fagnani>
Component:	generic-crash	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED WORKSFORME
Severity:	crash	CC:	kde
Priority:	NOR	Keywords:	qt6
Version First Reported In:	git-stable-Plasma/6.1
Target Milestone:	1.0
Platform:	Fedora RPMs
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	screenshot of plasmashell trace

Description Matt Fagnani 2024-06-04 15:50:55 UTC

Created attachment 170135 [details]
screenshot of plasmashell trace

SUMMARY

I was using Plasma 6.0.90 on Wayland in Fedora Rawhide QEMU/KVM VMs in GNOME Boxes using the llvmpipe driver in a Fedora 40 host. plasmashell sometimes crashed in SystemClipboard::checkClipData::ClipboardMode after copying and pasting files in nautilus. I've seen such crashes twice out of several times doing so. Two drkonqi windows appeared which showed the crash information couldn't be generated and had messages at the bottom saying that gdb had to be installed even though it was. The core dump of the second crash was removed due to following crashes in kded6, konsole, xdg-desktop-portal-kde. The Plasma session crashed again and went back to sddm. I'm writing out the top of the plasmashell trace from coredumpctl info in a screenshot I took in a VT.

#0 __pthread_kill_implementation
#1 raise
#2 KCrash::crashDefaultHandler
#3 __restore_rt
#4 SystemClipboard::checkClipData::ClipboardMode (plasma_engine_clipboard.so)
#5 doActivate
#6 KSystemClipboard::changed::ClipboardMode (libKF6GUIAddons.so.6)
#7 doActivate
...

I'm attaching the screenshot of the trace. I'll try to reproduce this problem to get a better trace. I didn't see this problem with Plasma 6.0.5 or earlier.

STEPS TO REPRODUCE
1. Boot a Fedora 40 KDE Plasma installation updated to 2024-6-4 with updates-testing enabled
2. Log in to Plasma 6.0.5 on Wayland
3. Start Konsole
4. Install GNOME Boxes if it isn't already with sudo dnf install gnome-boxes
5. Download Fedora-KDE-Live-x86_64-Rawhide-20240602.n.0.iso from https://koji.fedoraproject.org/koji/buildinfo?buildID=2459739
6. Start GNOME Boxes
7. Boot Fedora-KDE-Live-x86_64-Rawhide-20240531.n.0.iso in a GNOME Boxes QEMU/KVM VM with 3.5 GiB RAM, UEFI enabled, and 3D acceleration disabled using the llvmpipe mesa driver with a shared folder in the host
8. Start Konsole
9. journalctl --no-host > journalctl-selinux-policy-41.1-1-f41-systemd-generator-denials-1.txt
10. sudo dnf install nautilus
11. nautilus &
12. right-click on journalctl-selinux-policy-41.1-1-f41-systemd-generator-denials-1.txt and copy with the context menu 
12. Press Ctrl+L to select the location bar in nautilus
13. enter dav://localhost:9843 in the location bar
14. select the shared folder in the host
15. paste  journalctl-selinux-policy-41.1-1-f41-systemd-generator-denials-1.txt in the shared folder
16. If plasmashell didn't crash, repeat 12-15 until it does

OBSERVED RESULT
plasmashell sometimes crashed in SystemClipboard::checkClipData::ClipboardMode after copying and pasting files in nautilus

EXPECTED RESULT
No crashes should've happened.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora Rawhide
(available in About System)
KDE Plasma Version: 6.0.90
KDE Frameworks Version: 6.3.0
Qt Version: 6.7.1

ADDITIONAL INFORMATION

Comment 1 David Redondo 2024-06-05 07:47:04 UTC

Thank you for the bug report! Unfortunately I can't reproduce the crash myself on current git master, and the backtrace is missing debug symbols. 
Could you please install debug symbols and attach a new symbolicated backtrace generated by using coredumpctl gdb in a terminal window (in textt form)? See https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports#Retrieving_a_backtrace_using_coredumpctl for details about how to do this.
Thanks again!

Comment 2 Matt Fagnani 2024-06-05 12:56:51 UTC

The crashing function is SystemClipboard::checkClipData(QClipboard::Mode mode) based on https://invent.kde.org/plasma/plasma-workspace/-/blob/master/klipper/systemclipboard.cpp#L124 I've tried to reproduce this problem a few more times, but it hasn't happened again. I'll keep trying it. The problem might involve a race condition. Items that I've copied in the host usually showed up at the top of the clipboard in the VM and stayed there even after I copied something in the VM. Thanks.

Comment 3 Bug Janitor Service 2024-06-20 03:47:15 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
mark the bug 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 4 Bug Janitor Service 2024-07-05 03:47:33 UTC

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!

Comment 5 Matt Fagnani 2024-07-05 06:21:48 UTC

I didn't see this problem again when trying to reproduce it at least 10 times. The problem might be infrequent, or I might be missing some necessary step. Alternatively, the problem might have been fixed. I ran coredumpctl gdb with debuginfo packages installed on the first crash, but the VM ran out of memory and froze since gdb was using 1-2 GB.