usb/46176: Let's save the horse! [was: HEADSUP new usb code coming in.]

Alexey Shuvaev shuvaev at
Thu Aug 21 10:02:19 UTC 2008

On Wed, Aug 20, 2008 at 11:43:35PM +0200, Fabian Keil wrote:
> Warner Losh <imp at> wrote:
> > From: Bakul Shah <bakul at>
> > Subject: Re: HEADSUP new usb code coming in. 
> > Date: Tue, 19 Aug 2008 14:18:13 -0700
> > 
> > > 
> > > Accidentally unplugging a mounted USB disk (without
> > > unmounting it) resulted in a hang or a crash.  Is this fixed?
> > 
> > That's fixed in -current right now with the old stack.  It isn't a usb
> > issue at all, but a buffer cache issue.
> I can't confirm this for either msdosfs or geli (with ZFS).
> In case of msdosfs the situation has been vastly improved
> and the panic seems to be no longer guaranteed, but there's
> still a fair chance it'll happen eventually.
It was discussed now and then on freebsd-usb mailing list.
Have a look at

As for the non-msdosfs formatted media, I am quite sure it is a really bad
idea to unplug media before unmounting it (there is actually no difference
between "removable" and "stationary" drives).

Just my 0.02$,

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