Panic when disconnecting Coolpix L5 (was: Cannot get kernel core dump)

[Toomas Aas]

Wednesday 25 June 2008 17:24:58 kirjutas Pietro Cerutti:

> Toomas Aas wrote:

> | Are there known conditions under which the core dump really isn't
> | recorded, or am I simply missing something obvious?
>
> Yes, if the panic occurs before the filesystem supposed to contain the
> crash dumps is mounted. Is it the case?

No, the panic occurs when the system is in full multi-user mode and all 
filesystems are mounted, including  /home where I have configured the crash 
dumps. Swap partition /dev/ad0s1b is also active.

However, it just occurred to me that the system actually goes somewhat awry 
even before the panic occurs, so perhaps this is why the core dump is not 
recorded. The sequence of events is like this:

1. I attach a digital camera (Nikon Coolpix L5) via USB to my computer, which 
has Asrock K7S41GX motherboard, with onboard SiS 5571 USB controller. The 
camera is set to 'Mass storage' mode.

2. The system seems to recognize the camera with some success:

Jun 25 16:35:48 bsd root: Unknown USB device: vendor 0x04b0 product 0x020d bus 
uhub1
Jun 25 16:35:48 bsd kernel: umass0: <NIKON NIKON DSC COOLPIX L5, class 0/0, 
rev 1.10/1.00, addr 2> on uhub1
Jun 25 16:35:48 bsd kernel: da0 at umass-sim0 bus 0 target 0 lun 0
Jun 25 16:35:48 bsd kernel: da0: <NIKON DSC COOLPIX L5 > Removable Direct 
Access SCSI-2 device
Jun 25 16:35:48 bsd kernel: da0: 1.000MB/s transfers
Jun 25 16:35:48 bsd kernel: da0: 485MB (994304 512 byte sectors: 64H 32S/T 
485C)

However, at that point the machine pretty much stops responding. Clicking any 
icons in KDE has no effect. I can switch to another tty by pressing for 
example Alt+F3, but I cannot log in there (the login prompt appears but I 
can't type my login name).

3. I disconnect the camera and kernel panics. 

umass0: BBB reset failed, IOERROR
umass0: BBB bulk-in clear stall failed, IOERROR
umass0: at uhub1, port 2 (addr 2) disconnected
(da0:umass-sim0:0:0:0): lost device
(da0:dead-sim0):0:0:0): Synchronize cache failed, status == 0x39, scsi status 
== 0x0
Fatal trap 12: page fault while in kernel mode
fault virtual address = 0x0
fault code = supervisor write, page not present
instruction pointer = 0x20:0xc043fb4b
stack pointer = 0x28:0xd4cd4adc
frame pointer = 0x28:0xd4cd4af8
code segment = base 0x0, limit 0xfffff, type 0x1b
                     = DPL 0, pres 1, def32 1, gran 1
processor eflags = interrupt ennabled, resume, IOPL = 0
current process = 2 (g_event)
trap number = 12
panic: page fault
Uptime: 1m 20s

Instruction pointer and current process are always identical, I haven't 
compared all the other information.

$ nm -n /boot/kernel/kernel | grep c043fb
c043fb10 T xpt_done

Note that I haven't mounted the camera before disconnecting, so it's probably 
not the 'well known problem' described on Jeremy Chadwick's wiki page.

Any further ideas on how to debug such problem or which mailing list is more 
appropriate?

Thanks a lot,
--
Toomas