[BUG] MiniAudio Fatal Error System.AccessViolationException

[ShadowMarker789]

Work In Progress issue as I collect more information about the bug and issue.

Thank you for reporting a bug! To help us understand and fix the issue, please provide the following information:

Requirements:

• [✔] I have searched the existing issues to ensure this bug has not already been reported.
• [✔] I have provided a clear and concise description of the bug.
• [❌] I have provided detailed steps to reproduce the bug. (NEEDS WORK!)
• [❌] I have included a minimal reproducible example (MRE) if applicable. (NEEDS WORK!)
• [✔] I have provided error messages and stack traces if applicable.
• [✔] I have completed the environment information.

1. Describe the Bug

Mini Audio Backend has been observed to terminate the process by reading or writing invalid memory.

Fatal error. System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
at System.Array.GetLowerBound(Int32)
at SoundFlow.Abstracts.SoundComponent.Process(System.Span`1)
at SoundFlow.Components.Mixer.GenerateAudio(System.Span`1)
at SoundFlow.Abstracts.SoundComponent.Process(System.Span`1)
at SoundFlow.Abstracts.AudioEngine.ProcessGraph(IntPtr, Int32)
at SoundFlow.Backends.MiniAudio.MiniAudioEngine.AudioCallback(IntPtr, IntPtr, IntPtr, UInt32)

2. Steps to Reproduce

Not yet available, issue is intermittent!

3. Expected Behavior

Not to crash.

4. Current Behavior

Crashes.

5. Minimal Reproducible Example (MRE)

Unable to produce minimal example -- the issue is temperamental, and I am working on reproducing it.

6. Error Messages and Stack Trace (if applicable)

Fatal error. System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
   at System.Array.GetLowerBound(Int32)
   at SoundFlow.Abstracts.SoundComponent.Process(System.Span`1<Single>)
   at SoundFlow.Components.Mixer.GenerateAudio(System.Span`1<Single>)
   at SoundFlow.Abstracts.SoundComponent.Process(System.Span`1<Single>)
   at SoundFlow.Abstracts.AudioEngine.ProcessGraph(IntPtr, Int32)
   at SoundFlow.Backends.MiniAudio.MiniAudioEngine.AudioCallback(IntPtr, IntPtr, IntPtr, UInt32)

7. Environment (please complete the following information):

• SoundFlow Version: 1.0.4 from Nuget
• .NET Version: net9.0
• Operating System: Windows 10 Build 19045.5854
• Architecture: AMD64
• Audio Backend Used (if known): MiniAudio
• Specific Audio Hardware (if relevant): N/A

8. Affected Components/Modules (if known)

List any specific SoundFlow components, modifiers, providers, or extensions you believe are related to this bug.

• MiniAudio, SpectrumAnalyzer (possibly)

9. Impact

Uncatchable Crash

10. Possible Workaround (if known)

None

11. Additional Context

Intermittent issue, unable to capture minimal reproduction.

[ShadowMarker789]

I've triggered this bug four times so far, it is incredibly difficult to reproduce.

[LSXPrime]

The issue is likely related to the SIMD instructions used by the SpectrumAnalyzer's FFT functions. Vector extension implementation has been a challenge to me, while an initial release caused frequent crashes, I later tweaked it to reduce this issue. However, it still appears intermittently, and I will investigate this further.

[ShadowMarker789]

The issue is likely related to the SIMD instructions used by the SpectrumAnalyzer's FFT functions. Vector extension implementation has been a challenge to me, while an initial release caused frequent crashes, I later tweaked it to reduce this issue. However, it still appears intermittently, and I will investigate this further.

Is it? Because I hit this when running with all HW intrinsics off.

[LSXPrime]

Interesting. Was the issue caused by the SpectrumAnalyzer or the normal SoundPlayer? Were you able to identify the line number where it crashed?
Regarding SIMD, was SSE active at the time? (It typically falls back to SSE when AVX is unavailable.) Or does DOTNET_EnableHWIntrinsic disable both?

[ShadowMarker789]

Or does DOTNET_EnableHWIntrinsic disable both?

DOTNET_EnableHWIntrinsic does indeed disable both AVX and SSE. I was getting wrong data out of the FFT with the AVX implementation, and the SSE implementation was immediately failing with memory access violations.

I have confirmed that we are running the Scalar implementation of the FFT, but stepping through the code with the debugger to identify the path followed.

This particular crash does not happen often. I can be running my applet for multiple hours before having that crash occur.

However, I have suspicions that heap memory is being corrupted elsewhere.

In my particular application, after having MiniAudio playing for several minutes, if I close the application, I hit a memory access violation that should not be possible.

Which implies that heap corruption has occurred, but on the unmanaged heap.

Instead, my suspicions are directed at the MiniAudio backend.

This is difficult to debug, and I am currently observing behaviour and trying to make correlations here.

[ShadowMarker789]

For reference, I checked how long it took for that bug to manifest this time.

Uptime: [1.06:52:50.0213911]
Fatal error. System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
   at System.Array.GetLowerBound(Int32)
   at System.Array.Copy(System.Array, System.Array, Int32)
   at System.Collections.Generic.List`1[[System.__Canon, System.Private.CoreLib, Version=9.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].ToArray()
   at SoundFlow.Abstracts.SoundComponent.Process(System.Span`1<Single>)
   at SoundFlow.Components.Mixer.GenerateAudio(System.Span`1<Single>)
   at SoundFlow.Abstracts.SoundComponent.Process(System.Span`1<Single>)
   at SoundFlow.Abstracts.AudioEngine.ProcessGraph(IntPtr, Int32)
   at SoundFlow.Backends.MiniAudio.MiniAudioEngine.AudioCallback(IntPtr, IntPtr, IntPtr, UInt32)

One day's worth of audio playing. Oh dear.

[LSXPrime]

One day's worth of audio playing. Oh dear.

Haha, a whole day? I can't even imagine the scenario!

@ShadowMarker789, just merged @Windows10CE PR that potentially fixes this. Could you give the master branch a quick test when you get a chance?

[LSXPrime]

The latest release package (v1.1.0) now includes the changes from the @Windows10CE PR. This allows for direct testing using the NuGet package.

[ShadowMarker789]

I am testing this now.