tor-browser crashes opening about:support and shows "Gah! tab crashed" (nixos-20.03) #86356
Description
Describe the bug
After upgrading to nixos-20.03 and enabling pulseaudio support I started experiencing the "Gah! tab crashed" error too often, to the point that browsing sites with certain types of embedded media (mostly audio/video) instantly triggers the error (e.g browsing https://www.washingtonpost.com/).
While troubleshooting this I also noticed that opening about:support crashes not the tab but the browser. On the console I can see:
(...)
Apr 29 20:44:27.000 [notice] Bootstrapped 100% (done): Done
Apr 29 20:44:28.000 [notice] New control connection opened.
Apr 29 20:44:28.000 [notice] New control connection opened.
Fontconfig warning: "/nix/store/hj7n3mgfbs413mjcap0xyh29wy4ff84n-tor-browser-bundle-bin-9.0.9/share/tor-browser/TorBrowser/Data/fontconfig/fonts.conf", line 145: blank doesn't take any effect anymore. please remove it from your fonts.conf
Fontconfig warning: "/nix/store/hj7n3mgfbs413mjcap0xyh29wy4ff84n-tor-browser-bundle-bin-9.0.9/share/tor-browser/TorBrowser/Data/fontconfig/fonts.conf", line 145: blank doesn't take any effect anymore. please remove it from your fonts.conf
fatal allocator error: invalid uninitialized allocator usage
Redirecting call to abort() to mozalloc_abort
Exiting due to channel error.
Apr 29 20:44:32.000 [notice] Owning controller connection has closed -- exiting now.
Apr 29 20:44:32.000 [notice] Catching signal TERM, exiting cleanly.
zsh: segmentation fault (core dumped) tor-browser
This crash is present with default options (i.e. mediaSupport = false and pulseaudioSupport = false).
In addition, after several crashes Tor asks to start in "Safe mode". I'm not sure what safe mode disables but it allows opening about:support without crashing and/or triggering the segfault.
This seems to hint at some interaction with external libraries and my assumption that this is somehow related to pulseaudio.
To Reproduce
Steps to reproduce the behavior:
nix-env -iA tor-browser-bundle-bintor-browser- In the URL
about:support - browser will crash
Notify maintainers
@offlinehacker @matejc @doublec @thoughtpolice @joachifm @hax404 @scaredmushroom
Metadata
% nix-shell -p nix-info --run "nix-info -m"
- system: `"x86_64-linux"`
- host os: `Linux 5.6.7, NixOS, 20.03.git.034f307a86c (Markhor)`
- multi-user?: `yes`
- sandbox: `yes`
- version: `nix-env (Nix) 2.3.4`
- channels(root): `"nixos-20.09pre217261.a2e06fc3423"`
- nixpkgs: `/var/nixpkgs-channels/nixos
The following expression was used to enable mediaSupport and puseaudioSupport:
(...)
torbrowserWithAudio = pkgs.torbrowser.override {
mediaSupport = true;
pulseaudioSupport = true;
};
(...)
and installed with nix-env -iA torbrowserWithAudio.