Ambient Sound Callback Crashing on Exit

Question

Hello,

I am getting an ambient sound crash on exit, this is on Unreal Engine 4.4.3 with the WWise 4.4 integration.  I would guess this is due to the fact that the object that the callback is trying to operate on is either dereferenced memory or otherwise invalid.  Do you have an intended fix for this issue with 4.5?

This is the code where it crashes:

/*------------------------------------------------------------------------------------

AAkAmbientSound

------------------------------------------------------------------------------------*/

 

/**

 * Static callback for ambient sounds

 */

static void AkAmbientSoundCallback( AkCallbackType in_eType, AkCallbackInfo* in_pCallbackInfo )

{

AAkAmbientSound * pObj = ( (AAkAmbientSound *) in_pCallbackInfo->pCookie );

if( pObj )

{

pObj->Playing( false );

}

}

This is the call stack:  

> ShooterGame-Win64-Shipping.exe!AkAmbientSoundCallback(AkCallbackType in_eType=AK_EndOfEvent, AkCallbackInfo * in_pCallbackInfo=0x000000002351f900) Line 23 C++

  ShooterGame-Win64-Shipping.exe!CAkPlayingMgr::CheckRemovePlayingID(unsigned long in_PlayingID=0, CAkPlayingMgr::PlayingMgrItem * in_pItem=0x0000000020a3a880) Line 166 C++

  ShooterGame-Win64-Shipping.exe!CAkPBI::Term(bool __formal=false) Line 316 C++

  ShooterGame-Win64-Shipping.exe!CAkURenderer::PerformContextNotif() Line 979 C++

  ShooterGame-Win64-Shipping.exe!CAkAudioMgr::Perform() Line 387 C++

  ShooterGame-Win64-Shipping.exe!CAkAudioThread::EventMgrThreadFunc(void * lpParameter=0x0000000000000000) Line 84 C++

  kernel32.dll!BaseThreadInitThunk() Unknown

  ntdll.dll!RtlUserThreadStart() Unknown

 

Answer 1

It seems the AAkAmbientSound has been destroyed before the callback has been called. To safeguard against this, you can change the if( pObj ) to if( pObj && pObj->IsValidLowLevelFast(false) )

This should protect the call to "Playing".

Comments

This worked, thanks!

---

Hey Benoit,

Actually it looks like there are still scenarios where the AkAmbientSoundCallback will crash.  Sometimes the first two checks in IsValidLowLevelFast() will catch the error and sometimes it falls to this third check which then throws an exception on invalid memory access.

// Crashes trying to dereference this, which is invalid memory.
    if (*(void**)this == NULL)
    {
        UE_LOG(LogUObjectBase, Error, TEXT("Virtual functions table is invalid."));
        return false;
    }