From: Dmitry Torokhov <dtor@insightbb.com>
To: dave young <hidave.darkstar@gmail.com>
Cc: Greg KH <gregkh@suse.de>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] atkbd: cleanup only once
Date: Thu, 28 Jun 2007 01:18:35 -0400 [thread overview]
Message-ID: <200706280118.36052.dtor@insightbb.com> (raw)
In-Reply-To: <a8e1da0706262202i3af320a7gaec8a5f0680beb13@mail.gmail.com>
On Wednesday 27 June 2007 01:02, dave young wrote:
> 2007/6/27, 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
> >
> how about check ps2dev->serio in ps2_command before use it?
I don't think we ever set it to NULL. Does the patch below help any?
--
Dmitry
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
---
drivers/input/serio/serio.c | 2 ++
1 files changed, 2 insertions(+)
Index: work/drivers/input/serio/serio.c
===================================================================
--- work.orig/drivers/input/serio/serio.c
+++ work/drivers/input/serio/serio.c
@@ -769,8 +769,10 @@ static int serio_driver_remove(struct de
static void serio_cleanup(struct serio *serio)
{
+ mutex_lock(&serio->drv_mutex);
if (serio->drv && serio->drv->cleanup)
serio->drv->cleanup(serio);
+ mutex_unlock(&serio->drv_mutex);
}
static void serio_shutdown(struct device *dev)
next prev parent reply other threads:[~2007-06-28 5:18 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-27 10:59 [PATCH] atkbd: cleanup only once Dave Young
2007-06-27 3:01 ` dave young
2007-06-27 4:34 ` Dmitry Torokhov
2007-06-27 4:28 ` Greg KH
2007-06-27 4:59 ` Dmitry Torokhov
2007-06-27 5:02 ` dave young
2007-06-28 5:18 ` Dmitry Torokhov [this message]
2007-06-28 6:12 ` dave young
2007-06-27 5:27 ` Greg KH
2007-06-27 13:37 ` Dmitry Torokhov
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