Re: [PATCH] atkbd: cleanup only once

[Dmitry Torokhov <dtor@insightbb.com>]

On Wednesday 27 June 2007 00:28, Greg KH wrote:
> On Wed, Jun 27, 2007 at 12:34:09AM -0400, Dmitry Torokhov wrote:
> > Hi Dave,
> > 
> > On Wednesday 27 June 2007 06:59, Dave Young wrote:
> > > Hi,
> > > 
> > > If you press ctrl+alt+del several times as kernel booting (before user level bootin), the kernel will oops. I found the ps2_command is called more than once, then the ps2dev->serio maybe NULL pointer.
> > > 
> > > 2.6.22-rc5 and 2.6.22-rc6 have same result.
> > > 
> > > Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
> > > ---
> > > diff -upr linux/drivers/input/keyboard/atkbd.c linux.new/drivers/input/keyboard/atkbd.c
> > > --- linux/drivers/input/keyboard/atkbd.c	2007-06-27 10:38:37.000000000 +0000
> > > +++ linux.new/drivers/input/keyboard/atkbd.c	2007-06-27 10:37:39.000000000 +0000
> > > @@ -795,6 +795,11 @@ static int atkbd_activate(struct atkbd *
> > >  
> > >  static void atkbd_cleanup(struct serio *serio)
> > >  {
> > > +	static int flag;
> > > +
> > > +	if(flag)
> > > +		return;
> > > +	flag = 1;
> > 
> > Unfortunately this will prevent atkbd from resetting keyboard on 2nd
> > suspend attempt. It will also not work if you have an active MUX and
> > have a couple of keyboards connected.
> > 
> > Greg, now that you removed rwsem from subsystem (and subsystem itself
> > for that matter) there is nothing as far as I can see that stops
> > several threads from running device_shutdown() simultaneously. I also
> > do not see what would isolate device probing and shutting them down
> > at the same time. Am I missing something?
> 
> There was never anything stopping that from happening before.  No driver
> core code was using that rwsem, so it wasn't protecting anything,
> despite people trying to use it as if it was :)
> 

It did protect device_shutdown() from itself, didn't it?

-- 
Dmitry