"Fatal trap 12: page fault while in kernel mode" on 7.1/amd64, but not 7.0

[Boris Kochergin]

Ahoy. I recently upgraded an amd64 machine to 7.1-RELEASE, and started 
getting a bunch of these at a pretty high frequency (a few hours to a 
day apart):

http://acm.poly.edu/~spawk/IMG00033.jpg

The "current process" is always httpd. They're particularly annoying 
because the machine doesn't actually ever reboot, requiring manual 
intervention. Reverting the kernel back to 7.0 makes the panic go away, 
and the machine had been happily running 7.0 for about a year 
beforehand. I realize that the photo hardly contains any useful 
debugging information, but I was hoping it might look familiar to 
someone. If not, I guess I'll come back with a backtrace.

-Boris