Run auto config test several times, sometimes OBS will crash.

[EightJay]

Operating System Info

Windows 10

Other OS

No response

OBS Studio Version

Other

OBS Studio Version (Other)

30.1.2

OBS Studio Log URL

https://obsproject.com/logs/sbdvXu44lSfULNBu

OBS Studio Crash Log URL

https://obsproject.com/logs/S5FEASeCcYNKTfLn

Expected Behavior

app will not crash.

Current Behavior

Run auto config test several times, sometimes app will crash.And the crash reasons are same, the reason is about audio_callback.
debug source code - exception unhandled

Steps to Reproduce

1.click tools
2.click Auto-Configuration Wizard
3.click Next until stream warning and click Yes
4.sometimes when the bandwitdh test, app will crash cause by audio_callback.

And I try to debug source code, I find out the root cause is ”read access violiaton“, mx was nullptr.

In my opinion, according to my debug analysis, other thread(ucrtbased.dll thread) destroy the obs->video.mixes_mutex, and in
audio_callback function, pthrea_mutex_unlock will get the mixes_mutex which is nullpter.And crash happened.

Anything else we should know?

No response

Tasks

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[EightJay]

Maybe we have to ensure that mixes_mutex should be unlocked first and then we can destory the mixes_mutex.
AutoConfigTest will call obs_free_video function and finally destroy obs->video.mixes_mutex. But at that time, audio thread maybe hold the obs->video.mixes_mutex? I do not know how to fix this.

[EightJay]

it is a regression, commit id is [b05a401]. In my opinion, this change may not consider that auto config test will call obs_free_video, and destroy mixes_mutex, but at that time, audio thread need use this mutex which is destroyed by other thread.So exception happened.
And i try to use OBS-Studio-30.0-rc1-Full-Installer-x64.exe (b05a401 commit is not included) to test, obs can not reproduce this issue.

[RytoEX]

@exeldro @Lain-B regarding the linked commit.