koboldcpp: fail to run since tkinter is built separatly

[marius851000]

Nixpkgs version

• Unstable (25.11)

Describe the bug

When running koboldcpp on a recent nixpkgs branch, it run and open a window for a moment before immediatly closing and crashing.

Steps to reproduce

1. Execute nix run nixpkgs/f4b140d5b253f5e2a1ff4e5506edbf8267724bde#koboldcpp on a graphical session (Wayland/KDE on my tests)
2. Notice how the app open a window and immediatly close.

Expected behaviour

It open a window with various option as with nix run nixpkgs/205c2e95b565cd6bd10154eb3e9d0e8871911aa4#koboldcpp

Screenshots

No response

Relevant log output

***
Welcome to KoboldCpp - Version 1.98.1
For command line arguments, please refer to --help
***
FontManager error: [Errno 13] Permission denied: '/home/marius/.fonts/Roboto-Regular.ttf'
FontManager error: [Errno 13] Permission denied: '/home/marius/.fonts/Roboto-Medium.ttf'
FontManager error: [Errno 13] Permission denied: '/home/marius/.fonts/CustomTkinter_shapes_font.otf'
customtkinter.windows.widgets.font warning: Preferred drawing method 'font_shapes' can not be used because the font file could not be loaded.
Using 'circle_shapes' instead. The rendering quality will be bad!
Auto Selected Default Backend (flag=0)

fish: Job 1, 'nix run nixpkgs/f4b140d5b253f5e…' terminated by signal SIGSEGV (Address boundary error)

Additional context

Bisection show the problem appeared on 39df3445b6f2255a206a56e65ad9a5b08744ed1d, which does change related to tkinter. GDB provide the following backtrace, showing it indeed appear to be somehow related to tkinter:

#0  0x00007ffff60e35e5 in Tk_FreeGC () from /nix/store/z2fry9vqffvf9mxa74ch5nc3wgb3xp0z-tk-9.0.1/lib/libtcl9tk9.0.so
#1  0x00007ffff60fe64d in TkButtonWorldChanged () from /nix/store/z2fry9vqffvf9mxa74ch5nc3wgb3xp0z-tk-9.0.1/lib/libtcl9tk9.0.so
#2  0x00007ffff60fed9d in ConfigureButton () from /nix/store/z2fry9vqffvf9mxa74ch5nc3wgb3xp0z-tk-9.0.1/lib/libtcl9tk9.0.so
#3  0x00007ffff60ffae8 in ButtonWidgetObjCmd () from /nix/store/z2fry9vqffvf9mxa74ch5nc3wgb3xp0z-tk-9.0.1/lib/libtcl9tk9.0.so
#4  0x00007ffff564d1db in TclNRRunCallbacks () from /nix/store/zkvp5mrs2x620labv8gy506rrqdd9r35-tcl-9.0.1/lib/libtcl9.0.so
#5  0x00007ffff6875c77 in Tkapp_Call () from /nix/store/2pkyjgnxpj6hqkp8vy9v2s7rp1csvafw-python3.13-tkinter-3.13.7/lib/python3.13/site-packages/_tkinter.cpython-313-x86_64-linux-gnu.so
#6  0x00007ffff79d74c8 in method_vectorcall_VARARGS () from /nix/store/829wb290i87wngxlh404klwxql5v18p4-python3-3.13.7/lib/libpython3.13.so.1.0
#7  0x00007ffff7984ea8 in PyObject_Vectorcall () from /nix/store/829wb290i87wngxlh404klwxql5v18p4-python3-3.13.7/lib/libpython3.13.so.1.0
#8  0x00007ffff7bca97a in _PyEval_EvalFrameDefault () from /nix/store/829wb290i87wngxlh404klwxql5v18p4-python3-3.13.7/lib/libpython3.13.so.1.0
#9  0x00007ffff7a6c5ca in method_vectorcall () from /nix/store/829wb290i87wngxlh404klwxql5v18p4-python3-3.13.7/lib/libpython3.13.so.1.0
#10 0x00007ffff7ae15c4 in thread_run () from /nix/store/829wb290i87wngxlh404klwxql5v18p4-python3-3.13.7/lib/libpython3.13.so.1.0
#11 0x00007ffff78a128a in pythread_wrapper () from /nix/store/829wb290i87wngxlh404klwxql5v18p4-python3-3.13.7/lib/libpython3.13.so.1.0
#12 0x00007ffff749a97a in start_thread () from /nix/store/776irwlgfb65a782cxmyk61pck460fs9-glibc-2.40-66/lib/libc.so.6
#13 0x00007ffff7522d2c in __clone3 () from /nix/store/776irwlgfb65a782cxmyk61pck460fs9-glibc-2.40-66/lib/libc.so.6

System metadata

• system: "x86_64-linux"
• host os: Linux 6.16.7, NixOS, 25.11 (Xantusia), 25.11.20250915.0d7c158
• multi-user?: yes
• sandbox: yes
• version: nix-env (Nix) 2.31.1
• nixpkgs: /nix/store/hqgp14lgbpi50x2d4hx8bnw96r7gvy98-source

Notify maintainers

koboldcpp maintainers: @maxstrid @FlameFlag

tkinter maintainers: @mweinelt (I’ll only ping the change author to avoid pinging too many peoples)

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[mweinelt]

That looks like a permission error in your system at first glance. Can you make sure these paths are readable/accessible?

[TheTallestJJ]

I get the exact same behavior without the permission issues:

 ***
Welcome to KoboldCpp - Version 1.98.1
For command line arguments, please refer to --help
***
Auto Selected Default Backend (flag=0)

fish: Job 1, 'sudo koboldcpp' terminated by signal SIGSEGV (Address boundary error)

[4evy]

I was able to also replicate it on aarch64-darwin

I'll try to investigate

[4evy]

As a temporary workaround you can use --skiplauncher, tested with bartowski/Llama-3.2-1B-Instruct-GGUF

[4evy]

Fixed by #449539