Segfault in clutter_text_paint when password entry dialog is displayed or modified

[ParnBlade]

Environment

• Distribution: Linux Mint 22.2
• Muffin version: 6.4.1+xia
• Cinnamon version: 6.4.8+xia
• network-manager-gnome: 1.34.0+mint3
• Graphics: (run inxi -G and paste here)
• Graphics:
  Device-1: Intel Alder Lake-UP3 GT2 [Iris Xe Graphics] driver: i915 v: kernel
  Device-2: Chicony FJ Camera driver: uvcvideo type: USB
  Display: x11 server: X.Org v: 21.1.11 with: Xwayland v: 23.2.6 driver: X:
  loaded: modesetting unloaded: fbdev,vesa dri: iris gpu: i915 resolution:
  1: 1920x1080 2: 2560x1440 3: N/A
  API: EGL v: 1.5 drivers: iris,swrast platforms: gbm,x11,surfaceless,device
  API: OpenGL v: 4.6 compat-v: 4.5 vendor: intel mesa
  v: 25.0.7-0ubuntu0.24.04.2 renderer: Mesa Intel Iris Xe Graphics (ADL GT2)

Steps to reproduce

1. Configure an OpenVPN connection that requires password + TOTP authentication
2. Click on VPN connection in network applet to initiate connection
3. When the password dialog appears, either:
   • Start typing in the password field, OR
   • Click "Show password" toggle

Expected behaviour

Password dialog works normally, allowing input and visibility toggle.

Actual behaviour

Cinnamon crashes with segfault and restarts. The crash occurs during text rendering in the password entry widget.

Workaround

Using nmcli connection up "VPN_NAME" --ask from terminal works correctly.

Stack trace

cinnamon[5169]: segfault at 55f8902e399d ip 00007c3509dd3d61 sp 00007ffeda8c9a38 error 4 in libgobject-2.0.so.0.8000.0

#0  g_type_check_instance_is_fundamentally_a (libgobject-2.0.so.0 + 0x3cd61)
#1  g_object_get_qdata (libgobject-2.0.so.0 + 0x21bfb)
#2  cogl_pango_show_layout (libmuffin-cogl-pango-0.so.0 + 0x774a)
#3  clutter_text_paint (libmuffin-clutter-0.so.0 + 0xa8acf)
#4  clutter_paint_node_paint (libmuffin-clutter-0.so.0 + 0x8e16a)
...

Additional context

• Crash happens with both nm-applet (GTK) and Cinnamon's native network agent
• Crash is reproducible 100% of the time
• The issue seems related to ClutterText rendering when the password field content changes or visibility is toggled

[mtwebster]

What cinnamon theme are you using? There was an existing bug involving the 'hint text' that's put in these text entry fields.

I can't reproduce that crash in the latest Cinnamon version, nor this one, due to some changes in keyboard input, but I'm not fully convinced yet.

ref:
github.com/linuxmint/cinnamon/issues/12611

[ParnBlade]

Cinnamon theme: Mint-L-Dark-Aqua
GTK theme: Mint-L-Dark-Aqua
Icon theme: Mint-L-Aqua

The crash occurs specifically in the NetworkManager password dialog when:

• Typing characters in the password field
• Toggling "show password" visibility

Both nm-applet (GTK dialog) and cinnamon's native network agent trigger the crash.

Should I try reproducing with a different theme (like Mint-Y or Adwaita) to see if it's theme-related like #12611?

[ParnBlade]

Update: After switching themes (Mint-L-Dark-Aqua → Mint-Y-Dark → Mint-L-Dark-Aqua),
the bug no longer reproduces, even back on my original theme.

It seems the theme switch reset some internal state (cache?) that was causing the crash.

I'll monitor and report back if the issue returns.