another panic for your viewing pleasure

I think this one occured as a result of 
"cdcontrol -f /dev/acd1 p", but I can't be
sure. 

(kgdb) bt
#0  doadump () at /usr/src/sys/kern/kern_shutdown.c:240
#1  0xc04c7ce4 in boot (howto=0x100) at /usr/src/sys/kern/kern_shutdown.c:372
#2  0xc04c8088 in panic () at /usr/src/sys/kern/kern_shutdown.c:550
#3  0xc05eaa3c in trap_fatal (frame=0xd87e8c28, eva=0x0) at /usr/src/sys/i386/i386/trap.c:821
#4  0xc05ea702 in trap_pfault (frame=0xd87e8c28, usermode=0x0, eva=0x1c) at /usr/src/sys/i386/i386/trap.c:735
#5  0xc05ea29d in trap (frame=
      {tf_fs = 0xc0c30018, tf_es = 0xc4490010, tf_ds = 0xc4490010, tf_edi = 0x0, tf_esi = 0xc449cd00, tf_ebp = 0xd87e8c80, tf_isp = 0xd87e8c54, tf_ebx = 0xc448bd20, tf_edx = 0x0, tf_ecx = 0xc0661fa4, tf_eax = 0x1, tf_trapno = 0xc, tf_err = 0x0, tf_eip = 0xc04e4683, tf_cs = 0x8, tf_eflags = 0x10203, tf_esp = 0xd87e8c98, tf_ss = 0xc048f26e})
    at /usr/src/sys/i386/i386/trap.c:420
#6  0xc05dc1f8 in calltrap () at {standard input}:94
#7  0xc0493c28 in g_destroy_provider (pp=0xc448bd20) at /usr/src/sys/geom/geom_subr.c:425
#8  0xc0490bd5 in g_orphan_register (pp=0xc449cd00) at /usr/src/sys/geom/geom_event.c:143
#9  0xc0490cfc in one_event () at /usr/src/sys/geom/geom_event.c:169
#10 0xc0490f25 in g_run_events () at /usr/src/sys/geom/geom_event.c:202
#11 0xc0491f55 in g_event_procbody () at /usr/src/sys/geom/geom_kern.c:134
#12 0xc04b1080 in fork_exit (callout=0xc0491f30 <g_event_procbody>, arg=0x0, frame=0x0) at /usr/src/sys/kern/kern_fork.c:793