removing external usb hdd without unmounting causes reboot?

Jeremy Chadwick koitsu at
Wed Jul 18 17:06:00 UTC 2007

On Wed, Jul 18, 2007 at 06:30:44PM +0200, Momchil Ivanov wrote:
> On Wednesday 18 July 2007 17:41:04 Oliver Fromme wrote:
> > As Josh wrote, it's expected.  The problem is known
> > to exist for a long time already (probably as long
> > as FreeBSD itself exists), and if there was an easy
> > solution, certainly someone would have fixed it.
> I think this is a critical problem and needs to be addressed, avoiding it 
> doesn`t solve it.

I agree.

I also have a hard time believing that the reason it hasn't been fixed
is because "there isn't an easy fix".  I'm under the impression it
hasn't been fixed because either no one cares enough to fix it (using
the workaround as a scapegoat excuse), or because the majority of people
do not use USB-based storage devices.

All of this brings me back a few years when I went on a quest to write a
application that interfaced with a Logitech USB webcam for FreeBSD (for
a streaming fishtank camera).  I found that USB alternative indexes were
broken (the code was there, but did not work), which the camera relied
upon.  When I reported the issue to the FreeBSD USB stack maintainer at
the time (who will remain nameless since he enjoyed arguing rather than
fixing or working with me), I was told 2 things: "I just ported this
from NetBSD, don't blame me", "Alt. indexes aren't commonly used so I
don't really care".

So, based on my experience as documented above, I would say the reasons
I listed are dead on.

Bottom line here is that the kernel panics when removing a USB device
that has filesystems mounted.  This shouldn't happen.  Spitting out
errors on the console is one thing, but a panic is another.  Sometimes
things cannot be avoided (re: "unmount and you'll be fine"), such as
cats pulling on USB hub AC power cables and other such things.

If someone wants to work on this and needs devices/toys (thumb drives,
external enclosures + hard disks), let me know, I will be more than
happy to buy them the hardware needed.

| Jeremy Chadwick                                    jdc at |
| Parodius Networking                  |
| UNIX Systems Administrator                      Mountain View, CA, USA |
| Making life hard for others since 1977.                  PGP: 4BD6C0CB |

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