Crash: AVAudioUnit / AVAudioNode deallocated while CoreAudio still rendering (EXC_BAD_ACCESS in AUAudioUnitV2Bridge)

[aaravchour]

Amperfy 2.0.0 is crashing during audio playback due to an audio unit being deallocated while CoreAudio is still using it. The crash consistently occurs inside objc_msgSend when AUAudioUnitV2Bridge.invalidateAudioUnit is called on a freed object.

Crash summary:

• Exception: EXC_BAD_ACCESS (SIGSEGV)

• Location: objc_msgSend → AUAudioUnitV2Bridge.invalidateAudioUnit

• Thread: Background queue (source.queue)

• Likely cause: An AVAudioUnit / AVAudioNode is being released on a non‑main queue while the audio engine is still rendering.

Key stack trace:

Thread 14 Crashed:
objc_msgSend
AUAudioUnitV2Bridge.invalidateAudioUnit
AUInterfaceBaseV3::~AUInterfaceBaseV3
AVAudioNodeImpl::~AVAudioNodeImpl
AVAudioUnitImpl::~AVAudioUnitImpl
-[AVAudioNode dealloc]
AmperfyKit …
Interpretation:

This appears to be a race condition:
AVAudioNode or AVAudioUnit is torn down while CoreAudio still holds references to it. The deallocation happens on a custom dispatch queue, not the main thread, which may violate AVAudioEngine’s threading expectations.

Suggested areas to investigate:

• Ensure all AVAudioNode / AVAudioUnit teardown happens on the main thread.

• Stop the engine (engine.stop()) before removing or releasing nodes.

• Ensure no background queue is releasing audio objects while render callbacks are active.

• Verify that input/output streams are closed before node destruction.

Environment:

• macOS 26.3 (25D5087f)

• Apple Silicon (ARM64)

• Amperfy 2.0.0 (build 10)