Re: [PATCH] tty: Fix a USB serial crash/scribble

[Greg KH <greg@kroah.com>]

On Wed, Jul 22, 2009 at 12:16:31PM +0200, Daniel Mack wrote:
> On Wed, Jul 22, 2009 at 10:39:51AM +0100, Alan Cox wrote:
> > See if this one looks sensible. It does leave a tiny race window but that
> > semes wiser than hacking up the tty kref_put path in the middle of an -rc
> > series.
> > 
> > Thanks to Daniel and Alan Stern for chasing this down and getting traces. Also
> > to Daniel for being persistent when I took it as a random odd "only seen by one
> > user" error which it wasn't.
> 
> Thanks Alan for your patience. You know the tty layer well which I have
> no clue of, so I missed the bits in the close callback.
> 
> I tested your patch and can confirm it fixes the problem for me.
> 
> Daniel
> 
> 
> 
> > The port lock is used to protect the port state. However the port structure
> > is freed on a hangup, then the lock taken on a close. The right fix is to
> > drop the port on tty->shutdown() but we can't yet do that due to sleep v
> > non-sleeping rules. Instead do the next best thing and fix it up when we are
> > not in -rc season.
> > 
> > Reported-by: Daniel Mack <daniel@caiaq.de>
> > Signed-off-by: Alan Cox <alan@linux.intel.com>
> 
> Tested-by: Daniel Mack <daniel@caiaq.de>

Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

Alan, do you want me to send this to Linus, or will you?

thanks,

greg k-h