Looking for retainers of PINNED objects

Hi all, I'm profiling a fairly large program which seems to have a space leak. The heap profiling (-hc) shows that PINNED objects are accumulated over time. In order to check the retainers of the objects, I ran the retainer profiling. Unfortunately it didn't output anything with -hr -hcPINNED. Also, this is just a guess though, the retainer profiling without any filters (I mean just -hr) doesn't seem to include PINNED objects at all. Is there a way to check what retains the PINNED objects? Thanks, Mitsutoshi