vcv-rack 2.6.0: Fails to launch with segfault

[Herschenglime]

Nixpkgs version

• Unstable (25.05)

Describe the bug

When trying to launch vcv rack version 2.6.0 from the command line with Rack, the program fails to launch with the following error:

MESA-INTEL: warning: ../src/intel/vulkan/anv_formats.c:802: FINISHME: support YUV colorspace with DRM format modifiers
MESA-INTEL: warning: ../src/intel/vulkan/anv_formats.c:834: FINISHME: support more multi-planar formats with DRM modifiers
fish: Job 1, 'Rack' terminated by signal SIGSEGV (Address boundary error)

Before this, it pops up a window saying it crashed due to a buggy patch and if you'd like to try reopening it or starting with a blank one. No matter which option you choose, this still happens.

As far as I know its trying to open the default patch, but obviously I can't be sure because it doesn't ever make it into the UI.

Steps to reproduce

Launch VCV rack from the desktop file or the command line.

Observe that it fails to start.

Expected behaviour

VCV rack launches properly and enters the gui

Screenshots

No response

Relevant log output

Additional context

I'm not sure if 2.6.0 has ever worked for me, but I rolled back to version 2.5.1 with an overlay in my NixOS config and that launches succesfully, making me think its an issue with the new version.

System metadata

• system: "x86_64-linux"
• host os: Linux 6.12.19, NixOS, 25.05 (Warbler), 25.05.20250315.c80f6a7
• multi-user?: yes
• sandbox: yes
• version: nix-env (Nix) 2.24.12
• nixpkgs: /etc/nix/path/nixpkgs

Notify maintainers

@nathyong
@jpotier
@ddelabru

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[afh]

@Herschenglime could I interesting you in helping test #332358, which update VCV Rack to 2.6.2?

I'm curious if this issue is addressed by upstream changes or whether the nix package needs some attention…

[Herschenglime]

Hi @afh, thanks for the quick response! I just got a chance to build and try it out, unfortunately it's the same error except now there's also no text in the dialog.

I found https://www.reddit.com/r/vcvrack/comments/10jwjr9/222_on_linux_broken_after_update/ happening for someone else but way back for vcv 2.2.2.

I'd be willing to try deleting all my plugins, but I have no idea where they're stored on NixOS - I can't find the .Rack2 folder and it wasn't obvious to me that the plugins were installed in the nix store when I checked the path for Rack.

Thanks for your help!

[afh]

Thanks for giving it a spin, @Herschenglime, could you try and start Rack with a different user directory, e.g. Rack -u /tmp/vcv-test (see "Command line usage" from the VCV Manual)

Please replace Rack with whatever the executable is called on linux.

[afh]

FYI: I've updated #332358, so that the freshly released Rack 2.6.3 is being build.

[Herschenglime]

Sounds good! Just to confirm, I should try it with 2.6.3 then, right?

[afh]

Ideally yes 🙂

[husjon]

Hi @afh I just tried the latest commit in #332358 and it unfortunately still seem to segfault.

# After pulling down your branch
nixpkgs on  master 
❯   NIXPKGS_ALLOW_UNFREE=1 nix-build -A vcv-rack 
/nix/store/nya8rfsmwvz2120i8jhsi0aabnf0fxkn-vcv-rack-2.6.0

nixpkgs on  master 
❯ /nix/store/nya8rfsmwvz2120i8jhsi0aabnf0fxkn-vcv-rack-2.6.0/bin/Rack -u /tmp/vcv-test             
Could not open log at /tmp/vcv-test/log.txt
zsh: segmentation fault (core dumped)  /nix/store/nya8rfsmwvz2120i8jhsi0aabnf0fxkn-vcv-rack-2.6.0/bin/Rack -u 

Here's a gist with the output of both 2.6.3 and 2.5.1 (for reference)
https://gist.github.com/husjon/feb15961750f184668f71b01405cdf59

What I do see in 2.6.0 is GLFW error 65550: X11: Platform not initialized.
I am currently on Wayland but I do have XWayland.

Please do let me know if you want me to test anything else.

[afh]

Thanks for giving #332358 a spin, @husjon. I'm a bit surprised to see the version number 2.6.0 being reported in the gist you mentioned as well as the output path; I would've expected 2.6.3.

[Herschenglime]

Just got a chance to try as well with 2.6.3, unfortunately still segfaulting with a different user directory:

╰─❯ mkdir -p /tmp/vcv-home
╰─❯ Rack -u /tmp/vcv-home
libEGL warning: egl: failed to create dri2 screen
libEGL warning: egl: failed to create dri2 screen
Gdk-Message: 18:46:12.568: Error 71 (Protocol error) dispatching to Wayland display.
Gdk-Message: 18:46:12.669: Error 71 (Protocol error) dispatching to Wayland display.
fish: Job 1, 'Rack -u /tmp/vcv-home' terminated by signal SIGSEGV (Address boundary error)

I also got the log, which I've attached in this gist: https://gist.github.com/Herschenglime/ff7dd977e6e5a081b36425256328f51e

Seems like it's not detecting the software's version and as a result failing to load the core plugins, although I don't know much about VCV's internals.

Hope this helps!

[husjon]

Thanks for giving #332358 a spin, @husjon. I'm a bit surprised to see the version number 2.6.0 being reported in the gist you mentioned as well as the output path; I would've expected 2.6.3.

Yeah sorry about that, I had forgotten to tack on -b when I cloned your fork.
I get the same error as @Herschenglime.
I've updated my gist with logs from 2.6.3.

I also see is with 2.6.3, the dialog box asking to clear out the patch due to failure to launch either has invisible character or has not been able to populate the text (same as mentioned earlier in 2.6.2 #393113 (comment))

I did also try to create a completely empty template patch using 2.5.1 but it still segfaults.

[0.153 info adapters/standalone.cpp:239 main] Creating window
[0.197 info src/window/Window.cpp:292 Window] Window content scale: 1.000000
[0.239 info src/window/Window.cpp:344 Window] Renderer: AMD AMD Radeon RX 7800 XT (radeonsi, navi32, LLVM 19.1.7, DRM 3.61, 6.13.5)
[0.239 info src/window/Window.cpp:345 Window] OpenGL: 4.6 (Compatibility Profile) Mesa 25.0.2
[0.244 info src/window/Window.cpp:60 loadFile] Loaded font /nix/store/k4d261l4piamfgbq905vai0vgwgz1snk-vcv-rack-2.6.3/share/vcv-rack/res/fonts/DejaVuSans.ttf
[0.246 info src/window/Window.cpp:60 loadFile] Loaded font /nix/store/k4d261l4piamfgbq905vai0vgwgz1snk-vcv-rack-2.6.3/share/vcv-rack/res/fonts/NotoSansJP-Medium.otf
[0.250 info src/window/Window.cpp:60 loadFile] Loaded font /nix/store/k4d261l4piamfgbq905vai0vgwgz1snk-vcv-rack-2.6.3/share/vcv-rack/res/fonts/NotoSansSC-Medium.otf
[0.250 info src/window/Window.cpp:60 loadFile] Loaded font /nix/store/k4d261l4piamfgbq905vai0vgwgz1snk-vcv-rack-2.6.3/share/vcv-rack/res/fonts/NotoEmoji-Medium.ttf
[0.250 info src/patch.cpp:367 loadAutosave] Loading autosave /home/husjon/.local/share/Rack2/autosave/patch.json
[0.250 info src/patch.cpp:522 fromJson] Patch was made with Rack 2.5.1, current Rack version is 
[0.250 info adapters/standalone.cpp:274 main] Running window
[0.250 warn src/window/Window.cpp:258 errorCallback] GLFW error 65550: X11: Platform not initialized
[0.250 fatal adapters/standalone.cpp:49 fatalSignalHandler] Fatal signal 11. Stack trace:
/nix/store/k4d261l4piamfgbq905vai0vgwgz1snk-vcv-rack-2.6.3/bin/Rack: ?? +0x404e1f
/nix/store/rmy663w9p7xb202rcln4jjzmvivznmz8-glibc-2.40-66/lib/libc.so.6: ?? +0x1da40f30
/nix/store/wfrgia7qj3ijrxl9irsqvjfz20qqx5fm-libX11-1.8.12/lib/libX11.so.6: XkbGetState +0x18
/nix/store/k4d261l4piamfgbq905vai0vgwgz1snk-vcv-rack-2.6.3/lib/libRack.so: rack::window::Window::getMods() +0x2d
/nix/store/k4d261l4piamfgbq905vai0vgwgz1snk-vcv-rack-2.6.3/lib/libRack.so: rack::widget::EventState::handleHover(rack::math::Vec, rack::math::Vec) +0x9b
/nix/store/k4d261l4piamfgbq905vai0vgwgz1snk-vcv-rack-2.6.3/lib/libRack.so: rack::window::Window::step() +0x1ed
/nix/store/k4d261l4piamfgbq905vai0vgwgz1snk-vcv-rack-2.6.3/lib/libRack.so: rack::window::Window::run() +0x28
/nix/store/k4d261l4piamfgbq905vai0vgwgz1snk-vcv-rack-2.6.3/bin/Rack: main +0x9f6
/nix/store/rmy663w9p7xb202rcln4jjzmvivznmz8-glibc-2.40-66/lib/libc.so.6: ?? +0x1da2a1fe
/nix/store/rmy663w9p7xb202rcln4jjzmvivznmz8-glibc-2.40-66/lib/libc.so.6: __libc_start_main +0x89
/nix/store/k4d261l4piamfgbq905vai0vgwgz1snk-vcv-rack-2.6.3/bin/Rack: ?? +0x404c35

[husjon]

@Herschenglime I see that on your end it is in fact identifying Wayland, may I ask which compositor you're using? I'm using Hyprland.

[Herschenglime]

Hey @husjon, sorry for the late response. I'm just using Gnome 47.

I did also try to create a completely empty template patch using 2.5.1 but it still segfaults.

This is also interesting to me. I just rolled back to test it out again and 2.5.1 is still working as expected across 2 devices. Is the segfault for the same reason or something else on your end?

[afh]

I'm able to build and run Rack 2.6.3 on x86_64-linux from #332358 with NixOS 24.11. No text is shown in the menus and dialogs, so probably a font rendering issue, but also creating a new patch just leaves the whole VCV Rack empty.

[husjon]

Thanks @Herschenglime and no worries about delay, I am guilty of it too. 😄

I'm able to build and run Rack 2.6.3 on x86_64-linux from #332358 with NixOS 24.11.

@afh, both @Herschenglime and I are both on unstable so maybe there are some issues there.
I've tried rebuilding using packages from 24.11 but that also seem to fail with the same segfault.