[GH-ISSUE #411] Double free #864

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opened 2026-03-15 10:47:53 +03:00 by kerem · 3 comments

kerem commented

2026-03-15 10:47:53 +03:00

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Originally created by @NorfairKing on GitHub (Jul 27, 2020).
Original GitHub issue: https://github.com/asciinema/asciinema/issues/411

I'm getting this error while running asciinema in a nix build:

efree(): double free detected in tcache 2

To reproduce, check this out:

github.com/NorfairKing/smos@3badab7a55

Then run

nix-build nix/pkgs.nix -A smosCasts

I'm not sure how/why this would happen because this project looks to be written in Python, which I thought was memory-safe...

Originally created by @NorfairKing on GitHub (Jul 27, 2020). Original GitHub issue: https://github.com/asciinema/asciinema/issues/411 I'm getting this error while running `asciinema` in a nix build: ``` efree(): double free detected in tcache 2 ``` To reproduce, check this out: https://github.com/NorfairKing/smos/commit/3badab7a55eaf8799445956682b32e445c95f097 Then run ``` nix-build nix/pkgs.nix -A smosCasts ``` I'm not sure how/why this would happen because this project looks to be written in Python, which I thought was memory-safe...

kerem closed this issue

2026-03-15 10:47:58 +03:00

kerem commented

2026-03-15 10:48:06 +03:00

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@NorfairKing commented on GitHub (Jul 28, 2020):

I managed to reproduce this problem without nix sometimes but I also noticed that this problem doesn't occur when I run the nix build locally (a machine with a screen) but it does occur when I run the nix build remotely (on a machine without a screen).

Edit: scratch that, the problem also occurs locally.

@NorfairKing commented on GitHub (Jul 28, 2020): I managed to reproduce this problem without nix _sometimes_ but I also noticed that this problem doesn't occur when I run the nix build locally (a machine with a screen) but it _does_ occur when I run the nix build remotely (on a machine without a screen). Edit: scratch that, the problem also occurs locally.

kerem commented

2026-03-15 10:48:11 +03:00

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@ku1ik commented on GitHub (Dec 29, 2020):

I haven't heard about this problem on other distros, it seems to me like this is nix-specific.

Were you able to pinpoint the problem? I'm afraid my nix skills are close to zero.

@ku1ik commented on GitHub (Dec 29, 2020): I haven't heard about this problem on other distros, it seems to me like this is nix-specific. Were you able to pinpoint the problem? I'm afraid my nix skills are close to zero.

kerem commented

2026-03-15 10:48:16 +03:00

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@NorfairKing commented on GitHub (Dec 29, 2020):

It's definitely not a nix-specific problem because the problem occurs without nix as well.
I ended up just not using asciinema rec but generating the casts myself.

@NorfairKing commented on GitHub (Dec 29, 2020): It's definitely not a nix-specific problem because the problem occurs without nix as well. I ended up just not using `asciinema rec` but generating the casts myself.