[UPnP] Access to g_UserData must be protected

[enen92]

Description

Another easy one...access to the userdata map in UPnP must be lock protected before access. Those locks already exists on Register and Unregister. All those callbacks that are part of the diff are invoked by the library itself (thus from arbitrary threads) when remote renderers notify the player.

Found while sending bluray iso's from Kodi to another Kodi via UPnP. Since the simple menu is shown on the target player, it is not actually playing the file yet so playback is stopped on the "sender" and the "userdata" removed from the map (this should be fixed...). Later when you actually start the playback by selecting a track, the rendererer notifies the player of the event but the callback/userdata class no longer exists. If the callback happens when the userdata is being removed, kodi crashes.

[enen92]

Good to go?

[garbear]

Not very familiar with UPnP, but here it looks like a mutex was added correctly

[enen92]

Thanks garbear