Lua: require\\fiber.lua stack overflow ((null))

Environment

Second Life Release 7.1.9.10286089860 (64bit)
Release Notes

You are at 121.0, 110.0, 23.1 in Pasta Cake located at simhost-0a7de8a08a5d18b0e.agni
SLURL: http://maps.secondlife.com/secondlife/Pasta%20Cake/121/110/23
(global coordinates 332,153.0, 305,518.0, 23.1)
Second Life Server 2024-06-11.9458617693
Release Notes

CPU: 12th Gen Intel(R) Core(TM) i9-12900HK (2918.4 MHz)
Memory: 32440 MB
OS Version: Microsoft Windows 10 64-bit (Build 19044.3086)
Graphics Card Vendor: NVIDIA Corporation
Graphics Card: NVIDIA GeForce RTX 3050 Ti Laptop GPU/PCIe/SSE2

Windows Graphics Driver Version: 31.0.15.4659
OpenGL Version: 4.6.0 NVIDIA 546.59

Window size: 1278x1368
Font Size Adjustment: 96pt
UI Scaling: 1
Draw distance: 128m
Bandwidth: 10000kbit/s
LOD factor: 1.75
Render quality: 5
Texture memory: 4095MB
Disk cache: Max size 1638.4 MB (36.6% used)

J2C Decoder Version: KDU v7.10.4
Audio Driver Version: FMOD Studio 2.02.20
Dullahan: 1.14.0.202310131404
CEF: 118.4.1+g3dd6078+chromium-118.0.5993.54
Chromium: 118.0.5993.54
LibVLC Version: 3.0.16
Voice Server Version: Vivox 4.10.0000.32327.5fc3fe7c.5942f08

Packets Lost: 0/1,148 (0.0%)
August 09 2024 06:35:38

Description

This error was noticed in the logs after noticing a lua scripted floater stop updating.
WARNING #Lua# llcommon/lua_function.cpp(517) LuaState::~LuaState : atexit() function error: [string "C:\\Program Files\\SecondLifeLua\\scripts/lua/require\\fiber.lua"]:326: stack overflow ((null))

Reproduction steps

Not the most ideal steps but it does reproduce fairly consistently with the following:

1. Run the test_luafloater_speedometer.lua script
2. Leave it running for a few minutes
3. Use other apps outside of the viewer in the meantime
4. Return to the viewer, move your avatar and observe that the speedometer has stopped updating

Review the closed, merged pull request #2373 before investigating further. Reproduce the failure with test_luafloater_speedometer.lua, then inspect llcommon/lua_function.cpp around line 517 and the reported fiber.lua line 326; done means the floater continues updating without the Lua stack-overflow warning.