usb/105361: [panic] Kernel panic during unmounting mass storage (Creative mp3 player)

[M. Warner Losh]

In message: <200708241010.l7OAA7bl066026 at freefall.freebsd.org>
            "Rahul Siddharthan" <rsidd at online.fr> writes:
: The following reply was made to PR usb/105361; it has been noted by GNATS.
: 
: From: "Rahul Siddharthan" <rsidd at online.fr>
: To: bug-followup at freebsd.org, linimon at freebsd.org
: Cc:  
: Subject: Re: usb/105361: [panic] Kernel panic during unmounting mass storage (Creative mp3 player)
: Date: Fri, 24 Aug 2007 15:11:36 +0530
: 
:  linimon wrote:
:  > Does this panic occur if you umnount the device before removal? (We are
:  > aware of the problem if a device is removed before unmounting).
:  
:  I am experimenting with FreeBSD (7.0-CURRENT) after a few years.  My
:  USB stick was not initialised by the system: it was recognised but no
:  device node was created.  When I inserted and removed it a few times,
:  the system panicked.  (As I said, there was no device node, so no mounting.)
:  
:  I can submit a backtrace for this if anyone is interested.
:  
:  I followed the suggested change to usb_subr.c here:
:     http://lists.freebsd.org/pipermail/freebsd-questions/2006-February/112698.html
:  and, after this, the system creates a da0 device, and
:     mount -t msdosfs /dev/da0s1 /mnt
:  works.  I haven't yet got a panic by unmounting and removing, but removing
:  without unmounting does cause a panic still (as you say you are aware).
:  
:  Other than this issue FreeBSD-7 seems remarkably stable so far.   But this
:  problem with removable media has been around since floppy disk days, and
:  really seems to preclude using FreeBSD on any desktop machine where
:  uptime is important (eg, a compute workstation where long-term jobs
:  are running).

We only do the clear endpoint stall in FreeBSD 7 when the device has
been quirked to do a clearstall.  Is your device one that has this
quirk?

Warner