On Thu, Dec 20, 2007 at 10:32:50AM -0500, Alan Stern wrote:
> On Thu, 20 Dec 2007, Oliver Neukum wrote:
> 
> > Hi,
> > 
> > the mos7720 driver sends two commands to the device whenever it is
> > closed. It does so unconditionally even if the device has been disconnected.
> > It seems to me that this is wrong. Making sure that this does not happen
> > for disconnected devices takes a bit of infrastructure in the generic part.
> > However I am not sure whether this interfeeres with hanging up the tty.
> > What do you think?
> 
> There's nothing wrong with trying to send those commands if the device 
> really is disconnected.  The attempts will fail quickly.
> 
> The problem arises when the device is still connected but the driver 
> has been unbound.  That is illegal; a driver is never supposed to 
> access a device once its unbind method has returned.
> 
> Do other serial drivers suffer from a similar problem?

The io_edgeport-like devices all want to send a "flush" type command
when they are closed, and it doesn't look like they check for disconnect
either :(

I'm sure there are more, they should all probably be audited for this.
Although it is a very rare issue...

thanks,

greg k-h
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