I am reporting this issue on behalf of another user in my household. The affected machine is an HP EliteBook 830 G5 running Kubuntu 26.04.1 LTS.
We reproduced the crash on a fresh installation. After normal use, plasmashell repeatedly crashed with: SIGSEGV in FcCharSetHasChar() The backtrace showed libfontconfig and Qt font handling, including QFontEngineMultiFontConfig and QQuickLabel. On the affected system, before applying the workaround: $ fc-match sans-serif KaTeX_AMS-Regular.woff: "Noto Sans" "<unknown style>" The installed package was: fonts-katex 0.16.10+~cs6.1.0-5ubuntu1 We first purged fonts-katex and cleared the user's font cache, but the crash returned. The issue was resolved after also clearing the system fontconfig cache and rebuilding it: sudo rm -rf /var/cache/fontconfig/* rm -rf $HOME/.cache/fontconfig sudo fc-cache -f After that: $ fc-match sans-serif NotoSans-Regular.ttf: "Noto Sans" "Regular" The system has been stable so far after rebooting and normal use. Interestingly, the same machine had already experienced plasmashell crashes under Kubuntu 24.04, although we do not know whether those crashes were caused by the same underlying bug. This report may therefore be useful as another real-world reproduction of the current fontconfig/KaTeX cache issue. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2168311 Title: Default-installed fonts-katex crashes fontconfig (FcCharSetHasChar); Plasma won't start To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/node-katex/+bug/2168311/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
