Similar for me, easy to reproduce (3 times today).
Here's a kernel messages log, with 32 processes killed,
mostly hotplug, but also bash (2x), runltp, & some daemons.
I could not login and do anything else, but I could/did
SysRq-T, P, M, S, U, B to reboot. These are also in the log.
log:
http://developer.osdl.org/rddunlap/oom/oom_kill.txt
config:
http://developer.osdl.org/rddunlap/oom/config-2611rc2
on P4-UP, 1 GB RAM.
I saw this aswell. Appears to be the pipe leak cause it doesn't go nuts
with the patch at the bottom from Linus.