linux not using swap, but OOM killer is triggered

I've been having this problem for a long time now, and I can't seem to figure it out, basically, my linux (32bit 3.2.6-3.fc16.i686.PAE) system is refusing to use the swap. When I run

$ tail /dev/zero
tail: memory exhausted

it does not resort to using the swap at all.. it just dies after using up the physical RAM. Here are the relevant details.

$ free -m
             total       used       free     shared    buffers     cached
Mem:          8076       4652       3423          0        123        543
-/+ buffers/cache:       3985       4090
Swap:         8192        116       8076


$ cat /proc/sys/vm/swappiness 
60

$ ulimit -m
unlimited

$ cat /proc/sys/vm/overcommit_ratio
50

$ cat /proc/sys/vm/overcommit_memory 
0

I tried setting it to 1:

# sysctl vm.overcommit_memory=1
vm.overcommit_memory = 1


$ cat /proc/sys/vm/overcommit_memory 
1

and tried again, same result. Any ideas?