Probabilistic crash on zsh 5.9 on x86_64

[zsh bug report throwaway email thing <zsh.throwaway.eDjb3nwqw@xxxxxxxxx>]

Hello,

I would like to report a bug in zsh 5.9 (x86_64-pc-linux-gnu) (on Arch Linux, but I also reproduced on Alpine in QEMU, so it is probably zsh and not libc. Also, this does not happen in archiso in qemu, which is also weird.).

Repro instructions: run the commands:

TRAPEXIT() { ls }

TRAPEXIT

# if that does not crash, keep typing TRAPEXIT until it does. sometimes it doesn't crash.

Expected behavior: zsh might throw an error or something? but it shouldn't crash

Actual behavior: there is an unknown chance that zsh throws an error and crashes like this:

zsh: TRAPEXIT: function not defined by file
malloc(): unaligned tcache chunk detected

[1]    34511 IOT instruction (core dumped)  zsh

Nothing relevant in dmesg. 

If I can help in any way, please contact me.

Kind regards,

an anonymous bug reporter