Bug 2376024

Summary:	After upgrading qt6-qtwayland to 6.9.1-3, it causes segfault in libfcitx5platforminputcontextplugin.so and causes KDE Plasma desktop and Kate to crash multiple times
Product:	[Fedora] Fedora	Reporter:	KairikiFedora <1361138391>
Component:	qt6-qtwayland	Assignee:	Jan Grulich <jgrulich>
Status:	CLOSED CURRENTRELEASE	QA Contact:
Severity:	urgent	Docs Contact:
Priority:	unspecified
Version:	42	CC:	agurenko, germano.massullo, jgrulich, kde-sig, pg_forums, yanqiyu01
Target Milestone:	---	Keywords:	Desktop, Upgrades
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2025-11-12 08:19:58 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description KairikiFedora 2025-07-03 06:29:51 UTC

I read the contents of https://bugzilla.redhat.com/show_bug.cgi?id=2375356's latest reply, downloaded qt6-qtwayland, and then after the update is complete, using Kate and when typing, Kate crashes. By running sudo dmesg | grep kate, there is a libfcitx5platforminputcontextplugin.so related segfault.

Reproducible: Always

Steps to Reproduce:
1.Downloaded the rpm package with the content of the latest reply https://bugzilla.redhat.com/show_bug.cgi?id=2375356 and then updated qt6-qtwayland to 6.9.1-3 with dnf5
2.Run Kate
3.Typing any character
4.Kate crash
Actual Results:
Typing any character.Kate crash.

Expected Results:
Fixed the serious problem.

Additional Information:
dmesg massages:
[ 8524.083027] kate[1222868]: segfault at 3f ip 00007f6ff47223c0 sp 00007ffd4c4ea270 error 4 in libfcitx5platforminputcontextplugin.so[1d3c0,7f6ff4705000+2e000] likely on CPU 4 (core 0, socket 0)
[ 8537.955197] kate[1222925]: segfault at 3f ip 00007fe435aea3c0 sp 00007ffe468dadc0 error 4 in libfcitx5platforminputcontextplugin.so[1d3c0,7fe435acd000+2e000] likely on CPU 0 (core 0, socket 0)

Comment 1 pg_tips 2025-07-03 07:27:12 UTC

What version of fcitx5-qt6 are you using?

If it's a version that was rebuilt against the qt6-qtwayland 6.9.1-2 ABI, then revert to the previous version. qt6-qtwayland 6.9.1-3 restores the ABI from 6.9.1-1, so fcitx5-qt6 would need to match that.

Comment 2 KairikiFedora 2025-07-03 07:37:51 UTC

(In reply to pg_tips from comment #1)
> What version of fcitx5-qt6 are you using?
> 
> If it's a version that was rebuilt against the qt6-qtwayland 6.9.1-2 ABI,
> then revert to the previous version. qt6-qtwayland 6.9.1-3 restores the ABI
> from 6.9.1-1, so fcitx5-qt6 would need to match that.

6.9.1-2.fc42

Comment 3 KairikiFedora 2025-07-03 07:39:33 UTC

(In reply to March7thFedora from comment #2)
> (In reply to pg_tips from comment #1)
> > What version of fcitx5-qt6 are you using?
> > 
> > If it's a version that was rebuilt against the qt6-qtwayland 6.9.1-2 ABI,
> > then revert to the previous version. qt6-qtwayland 6.9.1-3 restores the ABI
> > from 6.9.1-1, so fcitx5-qt6 would need to match that.
> 
> 6.9.1-2.fc42

sorry write wrong.
It's 5.1.10-1.fc42

Comment 4 pg_tips 2025-07-03 07:46:05 UTC

So, based on https://discussion.fedoraproject.org/t/after-updating-qt6-qtwayland-to-6-9-1-3-kate-and-plasma-desktop-crash-again/157222/

I think what you are saying is:

qt6-qtwayland 6.9.1-3 + fcitx5-qt6 5.1.10-2 -> crashes

qt6-qtwayland 6.9.1-3 + fcitx5-qt6 5.1.10-1 -> no crashes, everything works fine


I assume fcitx5-qt6 5.1.10-2 is the version mentioned in https://bugzilla.redhat.com/show_bug.cgi?id=2375356#c27 that was built against the qt6-qtwayland 6.9.1-2 ABI.

So this seems expected: qt6-qtwayland 6.9.1-3 restores the 6.9.1-1 ABI, so you need a version of fcitx5-qt6 (like 5.1.10-1) that's compatible with that ABI.

Comment 5 Qiyu Yan 2025-07-03 11:06:11 UTC

(In reply to pg_tips from comment #4)
> I assume fcitx5-qt6 5.1.10-2 is the version mentioned in
> https://bugzilla.redhat.com/show_bug.cgi?id=2375356#c27 that was built
> against the qt6-qtwayland 6.9.1-2 ABI.

Yes, I wanted to push another build but unable to due to the DC move stopping me from submitting jobs to koji. Luckily, I was able to unpush https://bodhi.fedoraproject.org/updates/FEDORA-2025-bc6f6d5c13 before it reach stable (and crash more user's KDE). 

So in this case, I suggest that you (@March7thFedora) just downgrade to fcitx5-qt-5.1.10-1.fc42 .