USB fash devices and dd

[Soeren Straarup]

On Thu, 6 May 2004, Pawel Jakub Dawidek wrote:

> On Wed, May 05, 2004 at 06:16:10PM -0700, Gordon Tetlow wrote:
> +> On Wed, May 05, 2004 at 09:15:17AM -0700, Gordon Tetlow wrote:
> +> > On Tue, May 04, 2004 at 12:04:26PM +0200, Soeren Straarup wrote:
> +> > >
> +> > > Hi
> +> > >
> +> > > I was reading the vol_msdosfs thread and this is what i've seen IRL
> +> > >
> +> > > When dd'ing from a usb dongle to a file and then remove the dongle during
> +> > > this operation, then a kernel panic might ocour. I can't tell where the
> +> > > chain breaks. All this has been taken place on a 5.1-R box.
> +> >
> +> > Only "might occur"? I would have thought it would panic 100%! The correct
> +> > solution to this problem is "Don't do that"
> +>
> +> Despite my flippant response, this is a FAQ. I have heard some rumblings
> +> that this may be fixed One Day (tm), but I wouldn't hold my breath. The
> +> problem is deep in the kernel and is non-trivial to fix (from what I've
> +> been told anyway).
>
> AFAIR I was having simlar problem with gbde on usb bar (da0) when file
> system from this device was mounted. I was able to fix panic in gbde,
> I was able to fix cam(4), but I wasn't able to fix UFS (maybe I should
> try harder). Anyway, without mounted file system it should be possible
> to fix this quite easy.

My problem is, is it the usb code that panic or is it from the geom layer?

>
> --
> Pawel Jakub Dawidek                       http://www.FreeBSD.org
> pjd at FreeBSD.org                           http://garage.freebsd.pl
> FreeBSD committer                         Am I Evil? Yes, I Am!
>

Soeren Straarup   | aka OZ2DAK aka Xride
FreeBSD wannabe   | FreeBSD since 2.2.6-R
     Don't let your brain be in idle to long
      it might get stuck there