No details in call stack

I am using unity 5.6.2f1 64 bit build for building on android and ios.

When I run the game on mobile, android and ios - I get a ton of
NullReferenceException exception with this call stack (in the performance -> Reports section) :

UnityEngine.Component.GetComponents[BaseInput] ()
UnityEngine.EventSystems.BaseInputModule.get_input ()
UnityEngine.EventSystems.StandaloneInputModule.ProcessTouchEvents ()
UnityEngine.EventSystems.StandaloneInputModule.Process ()
UnityEngine.EventSystems.EventSystem.Update ()

I have no ideas where it is being triggered from. Any ideas on how I can enable call stack to point to where in my code is this being stemmed from ? Its easy to reproduce on android. I would fix it but then I need to know where to look.

Similarly, there is another call stack that I get for a different report:

BoardGame.UnityEngine.EventSystems.IDragHandler.OnDrag (UnityEngine.EventSystems.PointerEventData eventData)
UnityEngine.EventSystems.ExecuteEvents.Execute (IDragHandler handler, UnityEngine.EventSystems.BaseEventData eventData)
UnityEngine.EventSystems.ExecuteEvents.Execute[IDragHandler] (UnityEngine.GameObject target, UnityEngine.EventSystems.BaseEventData eventData, UnityEngine.EventSystems.EventFunction`1 functor)
UnityEngine.EventSystems.EventSystem:Update()

This is a function in my class, but is there a way for me to turn on what line number in that function is the NullReferenceException being thrown from ?

Also, I see a section on Manage Symbols, but I cannot figure out how to generate/upload symbols. Any thoughts ?

I'd appreciate any help on this.