Panic with umass device - trace included - unable to obtain dump

Hello!

  I've just bought one of those MP3 players that are supposed to work as 
an umass device. When I plug it in, I always get a "Fatal trap 12: page 
fault ...". Exact message and trace can be found towards the end of this 
mail. I've googled a bit but found nothing indicating that this is a 
known issue.
  I'm running 5.3-BETA4 FreeBSD 5.3-BETA4 and the kernel is built with 
debug symbols and other debug options enabled (WITNESS, GDB, etc.)

  I've also added "dumpdev" and "dumpdir" to /etc/rc.conf, but after I 
`reset` the PC from the db> prompt, I don't get any core dumps in 
/var/core; savecore just says "no dumps found" on boot.
  I've searched google and revealed [1]. I then tried to enter the 
debugger from the console and issued `panic` and I did get a core dump then.

  Now, I think there are two issues. The panic itself and my unability 
to debug it. Can anyone help me? I can offer more information on demand, 
even remote console access is possible.

Kind regards,

Phil.

[1]http://lists.freebsd.org/pipermail/freebsd-hackers/2004-May/006916.html

--- panic message below ---
> # umass0: vendor 0x10d6 Actions USB Disk Device, rev 1.10/1.00, addr 2
> da0 at umass-sim0 bus 0 target 0 lun 0
> da0: <ACTIONS USB DISK DEVICE 1.00> Removable Direct Access SCSI-2 device
> da0: 1.000MB/s transfers
> da0: 123MB (252509 512 byte sectors: 64H 32S/T 123C)
> umass0: BBB reset failed, STALLED
> umass0: BBB bulk-in clear stall failed, STALLED
> umass0: BBB bulk-out clear stall failed, STALLED
> (da0:umass-sim0:0:0:0): Synchronize cache failed, status == 0x4, scsi status == 0x0
> umass0: BBB reset failed, STALLED
> umass0: BBB bulk-in clear stall failed, STALLED
> umass0: BBB bulk-out clear stall failed, STALLED
> umass0: BBB reset failed, STALLED
> umass0: BBB bulk-in clear stall failed, STALLED
> umass0: BBB bulk-out clear stall failed, STALLED
> umass0: at uhub2 port 2 (addr 2) disconnected
> (da0:umass-sim0:0:0:0): lost device
> umass0: BBB reset failed, STALLED
> 
> 
> Fatal trap 12: page fault while in kernel mode
> fault virtual address   = 0xdeadc0ee
> fault code              = supervisor read, page not present
> instruction pointer     = 0x8:0xc05a7e3e
> stack pointer           = 0x10:0xd41febf0
> frame pointer           = 0x10:0xd41febf4
> 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         = 22 (irq11: uhci0)
> [thread 100016]
> Stopped at      usbd_clear_endpoint_toggle+0xa: calll   *0x10(%edx)
> db> tr
> usbd_clear_endpoint_toggle(c1ec6080,c1ec3b40,d41fec08,c243aa80,c24faa00) at usbd_clear_endpoint_toggle+0xa
> umass_clear_endpoint_stall(c24faa00,82,c1ec6080,9,c1f36300) at umass_clear_endpoint_stall+0x2b
> umass_bbb_state(c1f36500,c24faa00,11) at umass_bbb_state+0x41e
> usb_transfer_complete(c1f36500,c1f36554,d41fec94,0,c243aa00) at usb_transfer_complete+0x128
> uhci_idone(c1f3656c,c1f36554,0,0,c1b91000) at uhci_idone+0x11b
> uhci_check_intr(c1b91000,c1f3656c) at uhci_check_intr+0x80
> uhci_softintr(c1b91000,d41fece8,c059a907,c1b91000,c1ac83c0) at uhci_softintr+0x22
> usb_schedsoftintr(c1b91000,c1ac83c0,c197c800,c1982960,d41fecf4) at usb_schedsoftintr+0xd
> uhci_intr1(c1b91000,d41fed1c,c05e6930,c1b91000,0) at uhci_intr1+0x16b
> uhci_intr(c1b91000) at uhci_intr+0x28
> ithread_loop(c197c800,d41fed48,c197c800,c05e680c,0) at ithread_loop+0x124
> fork_exit(c05e680c,c197c800,d41fed48) at fork_exit+0xa4
> fork_trampoline() at fork_trampoline+0x8
> --- trap 0x1, eip = 0, esp = 0xd41fed7c, ebp = 0 ---
> db> reset
--- end of panic message ---

-- 
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