"umount -f" Complete system crash...

[illoai at gmail.com]

On 28/07/07, Modulok <modulok at gmail.com> wrote:
> BACKGROUND
> Someone brought me a camera they were having trouble with: winXP
> refused to mount the file system. I tried it on FreeBSD 6.1-RELEASE,
> "mount_msdosfs /dev/da0s1 /mnt", no problems. I recovered all of their
> photos. I attempted to "umount /mnt" and encountered an error,
> something along the lines of cannot contact device, (I don't remember
> exactly. No, I wasn't in the directory I was attempting to umount.).
> No other process was communicating with the device, according to the
> camera it was 'idle'. I issued a "umount -f /mnt" command. The entire
> system locked up for a few seconds (maybe 4) and then CRASH! I found
> myself looking at my BIOS output as the system reboots.
>
> QUESTIONS
> 1. Obviously, why did FreeBSD crash? (More specifically what could
> cause a crash in this situation?)
> 2. How do I find out, why it crashed?
> 3. Did I do something terribly unorthodox to invoke this crash, given
> the situation? If so, what could be done different?
>

The camera powered itself down after being
idle for a bit, perhaps?

There have been some recent discussions,
about physical disconnections of mounted
devices causing panics, on this list over the
last several weeks.

-- 
--