panic on mount_cd9660

FreeBSD hood.oook.cz 5.1-CURRENT FreeBSD 5.1-CURRENT #6: Mon Nov 10
20:26:12 CET 2003     root_at_hood.oook.cz:/usr/obj/usr/src/sys/PAV  i386

What I did:
1) insert SVCD in the CD-ROM drive
2) play some tracks from it. note /dev/acd0t1 /dev/acd0t2 etc...
3) remove SVCD from the CD-ROM drive
4) put data CD in the CD-ROM drive
5) mount_cd9660 /dev/acd0 /mnt/cdrom

What I got:
Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address   = 0x1c
fault code              = supervisor read, page not present
instruction pointer     = 0x8:0xc05a3073
stack pointer           = 0x10:0xcdce6c68
frame pointer           = 0x10:0xcdce6c80
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         = 2 (g_event)
trap number             = 12
panic: page fault
cpuid = 0; 

(kgdb) bt
#0  doadump () at /usr/src/sys/kern/kern_shutdown.c:240
#1  0xc0585991 in boot (howto=256) at /usr/src/sys/kern/kern_shutdown.c:372
#2  0xc0585ddf in panic () at /usr/src/sys/kern/kern_shutdown.c:550
#3  0xc06f6e96 in trap_fatal (frame=0xcdce6c28, eva=0) at /usr/src/sys/i386/i386/trap.c:821
#4  0xc06f6b12 in trap_pfault (frame=0xcdce6c28, usermode=0, eva=28) at /usr/src/sys/i386/i386/trap.c:735
#5  0xc06f6665 in trap (frame=
      {tf_fs = 24, tf_es = 16, tf_ds = 16, tf_edi = 0, tf_esi = -1025300736, tf_ebp = -842109824, tf_isp = -842109868, tf_ebx = -1008189440, tf_edx = 0, tf_ecx = -1065601612, tf_eax = 1, tf_trapno = 12, tf_err = 0, tf_eip = -1067831181, tf_cs = 8, tf_eflags = 66055, tf_esp = -1018716544, tf_ss = -842109800}) at /usr/src/sys/i386/i386/trap.c:420
#6  0xc06e2548 in calltrap () at {standard input}:94
#7  0xc054bf48 in g_destroy_provider (pp=0xc3e84000) at /usr/src/sys/geom/geom_subr.c:416
#8  0xc0548f25 in g_orphan_register (pp=0xc2e32700) at /usr/src/sys/geom/geom_event.c:143
#9  0xc054904c in one_event () at /usr/src/sys/geom/geom_event.c:169
#10 0xc0549275 in g_run_events () at /usr/src/sys/geom/geom_event.c:202
#11 0xc054a2a5 in g_event_procbody () at /usr/src/sys/geom/geom_kern.c:134
#12 0xc056dff0 in fork_exit (callout=0xc054a280 <g_event_procbody>, arg=0x0, frame=0x0) at /usr/src/sys/kern/kern_fork.c:793

(kgdb) up 7
#7  0xc054bf48 in g_destroy_provider (pp=0xc3e84000) at /usr/src/sys/geom/geom_subr.c:416
416             devstat_remove_entry(pp->stat);
(kgdb) list
411             KASSERT (pp->acw == 0, ("g_destroy_provider with acw"));
412             KASSERT (pp->acw == 0, ("g_destroy_provider with ace"));
413             g_cancel_event(pp);
414             LIST_REMOVE(pp, provider);
415             gp = pp->geom;
416             devstat_remove_entry(pp->stat);
417             g_free(pp);
418             if ((gp->flags & G_GEOM_WITHER))
419                     g_wither_geom(gp, 0);
420     }
(kgdb) print pp
$1 = (struct g_provider *) 0xc3e84000
(kgdb) print *pp
$2 = {name = 0x0, provider = {le_next = 0x0, le_prev = 0x0}, geom = 0x0, consumers = {lh_first = 0x0}, acr = 0, acw = 0, ace = 0, error = 0, orphan = {tqe_next = 0x0, tqe_prev = 0x0}, index = 0, 
  mediasize = 0, sectorsize = 0, stripesize = 0, stripeoffset = 0, stat = 0x0, nstart = 0, nend = 0, flags = 0}


-- 
Pav Lucistnik <pav_at_oook.cz>
What do we know about love? Love is like a pear. Pear is sweet and have
a specific shape. Try to exactly define the shape of a pear.
  -- Marigold: 50 Years Of Poetry