Greetings!! There is a tool called devloper workbench which must have this kind of functionality of finding the code which is calling that Sp. But if you are sure that the calling program is a function or procedure that what you do is get the definition from the syscat.procedures / functions on column BODY/TEXT. then grep for the SP which is being called.You will get the occuirences and it is one way to find who is calling this sp and auth id you can get it from syscat itself. We can discuss this more on call.
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