Having both Network replay and Voice chat enabled causes server to crash

We recently came across an issue where if both network replays and Voice chat are enabled whenever a client joins a server the server crashes. This is happening during a game, not when viewing a replay.

We found that the crash was happening when a player joined the server and it tries to (un)mute players for the system mute list. The issue is the DemoSpectator Controller has a Player State but not UniqueId (presumably because it’s not a real player).

Rough call stack:

FOnlineVoiceImpl::UpdateMuteListForLocalTalker (VoiceInterfaceImpl.cpp:546)
APlayerController::Server(Un)mutePlayer (PlayerController.cpp:3028)
FPlayerMuteList::Server(Un)MutePlayer (PlayerMuteList.cpp:27/54)
GetPlayerControllerFromNetId (GameSession.cpp:24)

APlayerController* GetPlayerControllerFromNetId(UWorld* World, const FUniqueNetId& PlayerNetId)
	// Iterate through the controller list looking for the net id
	for(FConstPlayerControllerIterator Iterator = World->GetPlayerControllerIterator(); Iterator; ++Iterator)
		APlayerController* PlayerController = *Iterator;
		// Determine if this is a player with replication
		if (PlayerController->PlayerState != NULL)
			// If the ids match, then this is the right player.
			if (*PlayerController->PlayerState->UniqueId == PlayerNetId) //Crash is here
				return PlayerController;
	return NULL;

Crash occurs when trying to dereference the UniqueId in the snippet above when the PlayerController is the Demo Spectator controller because it is NULL.

Hello ,

Thank you for reporting this issue. I’m currently in the process of setting up a reproduction case to try to get this to occur locally. I’ll be sure to let you know as soon as any significant progress has been made.

Awesome. If you need any more information to help reproduce it let me know and I’ll see what I can dig up

It seems that we may of found the issue and I would like to put a bug report in for it. Would you be able to post the entire callstack from the crash to go in the bug report?

Sorry it took me a bit to grab this, we were a bit busy over the last couple of days. The full call stack from the crash is attached. link text

Thank you for the callstack. I’ve placed a bug into our system for this issue under the number UE-22736. I’ll update you here whenever any changes have taken place or if I need any further information.