kmem_map too small panics with Soekris/Atheros access point

[Boris Kochergin]

Ahoy. I've got two Soekris Net5501s with Atheros 5212 cards in them, 
acting as access points. They are both running 7.2-RELEASE and at times 
each one has up to 30 machines associated with it. Relevant information 
about them can be found at "http://acm.poly.edu/~spawk/ap/". After a few 
days, they panic with:

panic: kmem_malloc(32768): kmem_map too small: 86142976 total allocated

Indeed, vm.kmem_size on each of them is 86228992. I had nowhere to write 
a core dump to, but the root issue seems to be that all kernel memory 
was exhausted, which sounds like a memory leak somewhere. Is that a 
known problem with that release and hardware configuration?

-Boris