Removing an SDHC card causes a kernel panic on -current

As follows, in "g_disk_providergone", a NULL pointer reference?:

imb_at_toshi:/home/imb> sudo less /var/crash/core.txt.4
toshi.auburn.protected-networks.net dumped core - see /var/crash/vmcore.4

Tue Jun 26 08:59:01 EDT 2012

FreeBSD toshi.auburn.protected-networks.net 10.0-CURRENT FreeBSD
10.0-CURRENT #12 r237599M: Tue Jun 26 07:52:01 EDT 2012
imb_at_toshi.auburn.protected-networks.net:/usr/obj/usr/home/imb/svn/head/sys/TOSHI
 i386

panic: page fault

[ .. ]

Unread portion of the kernel message buffer:
sdhci0-slot0: Card removed
mmc0: detached

Fatal trap 12: page fault while in kernel mode
cpuid = 1; apic id = 01
fault virtual address   = 0x0
fault code              = supervisor read, page not present
instruction pointer     = 0x20:0xc070a4bc
stack pointer           = 0x28:0xc6fb7c54
frame pointer           = 0x28:0xc6fb7c54
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 14 (g_event)
trap number             = 12
panic: page fault
cpuid = 1
Uptime: 7m8s
Physical memory: 3045 MB
Dumping 265 MB: 250 234 218 202 186 170 154 138 122 106 90 74 58 42 26 10

Reading symbols from /boot/kernel/drm.ko...Reading symbols from
/boot/kernel/drm.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/drm.ko
Reading symbols from /boot/kernel/i915.ko...Reading symbols from
/boot/kernel/i915.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/i915.ko
Reading symbols from /boot/modules/vboxdrv.ko...done.
Loaded symbols for /boot/modules/vboxdrv.ko
Reading symbols from /boot/modules/cuse4bsd.ko...done.
Loaded symbols for /boot/modules/cuse4bsd.ko
Reading symbols from /boot/modules/vboxnetflt.ko...done.
Loaded symbols for /boot/modules/vboxnetflt.ko
Reading symbols from /boot/modules/vboxnetadp.ko...done.
Loaded symbols for /boot/modules/vboxnetadp.ko
Reading symbols from /usr/local/modules/fuse.ko...done.
Loaded symbols for /usr/local/modules/fuse.ko
#0  doadump (textdump=1) at pcpu.h:244
244     pcpu.h: No such file or directory.
        in pcpu.h
(kgdb) #0  doadump (textdump=1) at pcpu.h:244
#1  0xc07ae76c in kern_reboot (howto=260)
    at /usr/home/imb/svn/head/sys/kern/kern_shutdown.c:449
#2  0xc07aee41 in panic (fmt=0x104 <Address 0x104 out of bounds>)
    at /usr/home/imb/svn/head/sys/kern/kern_shutdown.c:637
#3  0xc0af13d1 in trap_fatal (frame=0xc6fb7c14, eva=40)
    at /usr/home/imb/svn/head/sys/i386/i386/trap.c:1022
#4  0xc0af16a8 in trap_pfault (frame=0xc6fb7c14, usermode=0, eva=0)
    at /usr/home/imb/svn/head/sys/i386/i386/trap.c:936
#5  0xc0af29ef in trap (frame=0xc6fb7c14)
    at /usr/home/imb/svn/head/sys/i386/i386/trap.c:546
#6  0xc0adcbdc in calltrap ()
    at /usr/home/imb/svn/head/sys/i386/i386/exception.s:169
#7  0xc070a4bc in g_disk_providergone (pp=0xcb33ab80)
    at /usr/home/imb/svn/head/sys/geom/geom_disk.c:505
#8  0xc070f8ba in g_destroy_provider (pp=0xcb33ab80)
    at /usr/home/imb/svn/head/sys/geom/geom_subr.c:643
#9  0xc070fb6e in g_wither_washer ()
    at /usr/home/imb/svn/head/sys/geom/geom_subr.c:462
#10 0xc070cb62 in g_run_events ()
    at /usr/home/imb/svn/head/sys/geom/geom_event.c:289
#11 0xc077bd8b in fork_exit (callout=0xc070de54 <g_event_procbody>,
arg=0x0,
    frame=0xc6fb7d08) at /usr/home/imb/svn/head/sys/kern/kern_fork.c:995
#12 0xc0adcc84 in fork_trampoline ()
    at /usr/home/imb/svn/head/sys/i386/i386/exception.s:276
(kgdb)