CAkBankMgr random crash while loading soundbank

Question

I upgraded to Wwise 2017.2.1 build 6524 and now it randomly crashes 1 in 20 times or so while loading sound banks. Happens on Windows 10 and Linux.

Seems to happen more often when a debugger is attached. In fact I think it happens every single time on Linux, but only when gdb is attached

Unhandled exception thrown: read access violation.
pDevice was nullptr.

>    deceiver.exe!CAkBankMgr::ReadBus(const AkBank::AKBKSubHircSection & in_rSection, CAkUsageSlot * in_pUsageSlot) Line 2700    C++    Symbols loaded.
     deceiver.exe!CAkBankMgr::ProcessHircChunk(CAkUsageSlot * in_pUsageSlot, unsigned long in_dwBankID) Line 2109    C++    Symbols loaded.
     deceiver.exe!CAkBankMgr::LoadBank(CAkBankMgr::AkBankQueueItem in_Item, CAkUsageSlot * & out_pUsageSlot, CAkBankMgr::AkLoadBankDataMode in_eLoadMode, bool in_bIsFromPrepareBank, bool in_bDecode) Line 853    C++    Symbols loaded.
     [Inline Frame] deceiver.exe!CAkBankMgr::LoadBankPre(CAkBankMgr::AkBankQueueItem &) Line 930    C++    Symbols loaded.
     deceiver.exe!CAkBankMgr::ExecuteCommand(CAkBankMgr::AkBankQueueItem & in_Item) Line 476    C++    Symbols loaded.
     [Inline Frame] deceiver.exe!CAkThreadedBankMgr::ExecuteCommand() Line 192    C++    Symbols loaded.
     deceiver.exe!CAkThreadedBankMgr::BankThreadFunc(void * lpParameter) Line 134    C++    Symbols loaded.

Here's the stack trace on Linux:

#0 CAkBankMgr::ReadBus (this=this@entry=0x7fffc411e4d0, in_rSection=..., in_pUsageSlot=in_pUsageSlot@entry=0x7fffc4160b18) at ../Common/AkBankMgr.cpp:2700
#1 0x000000000092ef22 in CAkBankMgr::ProcessHircChunk (this=this@entry=0x7fffc411e4d0, in_pUsageSlot=0x7fffc4160b18, in_dwBankID=in_dwBankID@entry=1835346959) at ../Common/AkBankMgr.cpp:2109
#2 0x0000000000933352 in CAkBankMgr::LoadBank (this=this@entry=0x7fffc411e4d0, in_Item=..., out_pUsageSlot=@0x7fffedaaac60: 0x7fffc4160b18, in_eLoadMode=in_eLoadMode@entry=CAkBankMgr::AkLoadBankDataMode_OneBlock, in_bIsFromPrepareBank=in_bIsFromPrepareBank@entry=false, in_bDecode=in_bDecode@entry=false) at ../Common/AkBankMgr.cpp:853
#3 0x0000000000933510 in CAkBankMgr::LoadBankPre (this=0x7fffc411e4d0, in_rItem=...) at ../Common/AkBankMgr.cpp:930
#4 0x00000000009ec1c3 in CAkThreadedBankMgr::ExecuteCommand (this=this@entry=0x7fffc411e4d0) at ../Common/AkThreadedBankMgr.cpp:192
#5 0x00000000009ec248 in CAkThreadedBankMgr::BankThreadFunc (lpParameter=0x7fffc411e4d0) at ../Common/AkThreadedBankMgr.cpp:134
#6 0x00007ffff74807fc in start_thread (arg=0x7fffedaab700) at pthread_create.c:465
#7 0x00007ffff5f59b5f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

I have a Windows minidump if needed.

Answer 1

I think I solved this by moving the init stuff to another thread.

Answer 2

There's a potential race condition here. The CAkOutputMgr isn't initialized until CAkAudioThread::EventMgrThreadFunc starts, so if that thread gets held up and you load a bank very shortly after AK::SoundEngine::Init, you can crash.

You can wait for a Global or Device Status callback to be sure the audio thread is ready, but I think that might still hang if there is no valid audio device, or if it's suspended. I think the real fix will have to come from AK.