panic with racct

Hi,

I get this panic:

Fatal trap 18: integer divide fault while in kernel mode
cpuid = 4; apic id = 04
instruction pointer     = 0x20:0xffffffff808f0c23
stack pointer           = 0x28:0xffffff83693b8b40
frame pointer           = 0x28:0xffffff83693b8ba0
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 21 (racctd)

with these options added to my kernel:

options RCTL
options RACCT

This is with r242578. Removing them avoids the issue. The relevant code
seems to be:

% addr2line -e /boot/kernel.old/kernel 0xffffffff808f0c23
/usr/src/sys/kern/kern_racct.c:1142

Let me know if more info is needed, or if I should file a PR.

Thanks,
Steve