AVCaptureSession startRunning crash

[Lev Sokolov]

Describe the bug

I'm getting a lot of crashes in Crashlytics with the following error:

Fatal Exception: NSGenericException
-[AVCaptureSession startRunning] startRunning may not be called between calls to beginConfiguration and commitConfiguration

Frame	Image	Call
0	CoreFoundation	__exceptionPreprocess
1	libobjc.A.dylib	objc_exception_throw
2	AVFCapture	-[AVCaptureSession startRunning]
3	HaishinKit	IOMixer.startCaptureSession()
4	HaishinKit	thunk for @escaping @callee_guaranteed () -> ()
5	libdispatch.dylib	_dispatch_call_block_and_release
6	libdispatch.dylib	_dispatch_client_callout
7	libdispatch.dylib	_dispatch_lane_serial_drain
8	libdispatch.dylib	_dispatch_lane_invoke
9	libdispatch.dylib	_dispatch_workloop_worker_thread
10	libsystem_pthread.dylib	_pthread_wqthread
11	libsystem_pthread.dylib	start_wqthread

This started happening after updating from 1.4.5 to 1.5.2.

Looks like the crash happens during the queue block invocation. I checked every beginConfiguration() call in the project and all of them are wrapped by lockQueue. beginConfiguration also isn't called externally. Maybe it's called somewhere where I didn't notice without a queue? Could you please help me to figure out the source of this crash?

To Reproduce

I don't have steps to reproduce it yet.

Expected behavior

No crash

Version

1.5.2

Smartphone info.

Happens on all kind of devices with iOS 15-16-17

Additional context

No response

Screenshots

No response

Relevant log output

No response

[shogo4405]

It appears that the main thread and the netStream.lockQueue thread are mixed, causing a race condition.

HaishinKit.swift/Sources/Media/IOMixer.swift

Lines 432 to 442 in 0f8b325

 private func willEnterForeground(_ notification: Notification) { 
     resumeCaptureSessionIfNeeded() 
     if #available(iOS 16, *) { 
         guard !session.isMultitaskingCameraAccessEnabled else { 
             return 
         } 
     } 
     videoIO.capture.attachSession(session) 
     videoIO.multiCamCapture.attachSession(session) 
 } 
 #endif