page fault in sched_add_internal on RELENG_5 with ULE + PREEMPTION

[Kris Kennaway]

quad-cpu amd64 package machine running RELENG_5 with ULE and
PREEMPTION, panicked with:

Mar 17 19:51:58 fbsd-amd64 kernel: pid 8261 (try), uid 0: exited on
signal 10 (core dumped)
kernel trap 12 with interrupts disabled


Fatal trap 12: page fault while in kernel mode
cpuid = 2; apic id = 02
fault virtual address   = 0x230
fault code              = supervisor read, page not present
instruction pointer     = 0x8:0xffffffff8039080f
stack pointer           = 0x10:0xffffffffbe420a60
frame pointer           = 0x10:0xffffff03e1380c60
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = resume, IOPL = 0
current process         = 44 (irq30: mpt1)
trap number             = 12
panic: page fault
cpuid = 2
panic: mi_switch: switch in a critical section
cpuid = 2
panic: mi_switch: switch in a critical section
cpuid = 2
[...]

readelf shows that the IP is in:

ffffffff803907d0 sched_add_internal

Kris