Stability Matrix hang on Linux traced to 143 Windows fonts breaking Fontconfig
Signal_Care6558 · reddit · 2026-09-25
A Linux user found Stability Matrix 2.16.4 hanging at startup with one CPU core pegged at 100%, no crash or error. After ruling out AMD drivers, Mesa, and GPU rendering, they attached gdb to the hung process and found the main thread stuck in libSkiaSharp.so at skfontmgrrefdefault() → FcPatternGetString() — SkiaSharp's font manager looping against Fontconfig.
The culprit: 143 Windows font files in /usr/local/share/fonts/windowsfonts. Moving the directory aside made Stability Matrix launch instantly; restoring it brought the hang back. Final fix:
- rm -rf /.cache/fontconfig
- sudo fc-cache -f -v
After rebuilding the caches, all 143 Windows fonts could stay installed with normal startup. Tip: if Stability Matrix hangs on Linux with one core at 100%, test by temporarily removing large font collections before blaming the GPU.
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