I guess the answer to this question all depends on how you run the reaction. Under strong enough conditions, you will get adipic acid (using chromic anhydride, etc...). If not, I would guess you'll get 6-hydroxyhexanoic acid, which may eliminate under acidic conditions to give 5-hexenoic acid (although this reaction isn't usually done with KMnO4 - usually done with ironsulfate and copper).
I'm guessing that if you tried to run this reaction, you'd end up with somewhat of a mess on your hands, forming a mixture of a bunch of the things listed above. Maybe I'm missing something, but that would be my answer based on a quick look in the literature.