This problem was encountered when calling a function (using gdb.parse_and_eval()) in a Python inferior that returns a PyObject *. This is the result of a debug session with Pdb (the Python Debugger) inside gdb:
(Pdb) print gdbval
<unknown at remote 0x-80f8220>
(Pdb) print gdbval.address
(Pdb) print gdbval.type
As you can see, the address is negative when you print the value or try to convert it to a Python long.
I tried to reproduce this but couldn't. Not too much info to work with here. Do you have a more specific reproducer?
Probably a dup.
*** This bug has been marked as a duplicate of bug 20126 ***