Bug 14310

The system panics while running "vinum start" out of /etc/rc, apparently
when updating the vinum configuration (the last console output before
the panic is "vinum: updating configuration from /dev/da0b").  This only
happens when running from an MFS root filesystem, and only for single
processor systems (either one processor in hardware or a dual processor
system without SMP defined in the kernel will panic.  A dual processor
system with SMP defined will work).  The panic message is:

Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0x10
fault code              = supervisor read, page not present
instruction pointer     = 0x8:0xc02ae313
stack pointer           = 0x10:0xc9457c44
frame pointer           = 0x10:0xc9457c98
code segment            = base rx0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 18 (vinum)
interrupt mask          = 
trap number             = 12
panic: page fault


where 0xc02ae313 is past the end of the kernel address space, presumably
in the vinum module.

How-To-Repeat: Create an MFS root filesystem and a generic kernel, both with unused
bits stripped out to save space.  On a system with vinum partitions
(for e.g. /usr), load the kernel, vinum.ko, and the MFS root out of the
loader and boot single user.  A "vinum start" will cause the panic.