USB storage corruption/panic when doing file IO and unplugging (another, non-storage) device

[Garrett Cooper]

On Thu, Oct 6, 2011 at 9:30 PM, Adrian Chadd <adrian at freebsd.org> wrote:
> Hi,
>
> I've noticed a strange issue with 9.0-BETA3. I haven't tried this on
> any previous 9.0 installs, I'm sorry, so I don't know when it began.
>
> If I'm doing some disk IO (say svn checkout, kernel building, watching
> a movie) on a USB device, whilst adding/removing non-storage USB
> devices (specifically here, unsupported wifi devices so I can get
> their device/vendor IDs), I reliably see failed read/write IO
> transactions. This ends up causing an eventual panic.
>
> Has anyone seen this before?
>
> This is _not_ plug/unplug the active storage device, or another
> storage device. This is when doing IO on a storage device (whether the
> root device or a media device) whilst plug/unplug a non-storage USB
> device (wifi chipsets w/ no driver.)

    Yeah. Ran into it earlier on in the 9.x cycle with twa unplugging
a USB keyboard when I was rebooting a machine; the panic was fixed in
twa, not ukbd. I suppose my question is: does this only happen with
USB, or is firewire affected, and why aren't the devices being
properly masked against interrupts [in the same queue??] [by
newbus???]?
Thanks,
-Garrett