A function which does not return (such as one that contains an infinite loop) doesn't need to save the return address register, so the compiler may reuse it for some other purpose. When this happens, the debugger may show strange things, especially if the non-returning function itself calls a function, in which case the debugger will get confused and show in the call stack view an infinite recursion of the nested function, which is not correct. The bug is that the DWARF information wasn't updated to indicate that the return address register is invalid, which would have stopped the debugger from trying to interpret it.