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Date: Thu, 27 Sep 2012 18:48:42 +0400
From: Cyrill Gorcunov <gorcunov@openvz.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Pavel Emelyanov <xemul@parallels.com>, Jiri Slaby <jslaby@suse.cz>
Subject: Re: [RFC] tty: Add get- ioctls to fetch tty status
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On Thu, Sep 27, 2012 at 07:43:44AM -0700, H. Peter Anvin wrote:
> >>If you can't guarantee that ALL those processes are stopped and
> >>checkpointed/restarted, you have a huge problem.
> >
> >Well, sure inside our tool before doing checkpoint we stop all
> >tasks which are part of dumpee process tree. This unfortunatly
> >doesn't apply to these ioctl calls. Peter, any idea how to deal
> >with that?
> 
> Sorry, no.  I suspect you might be trying to do something that is
> impossible to do in a general fashion without application changes.

I see. What if I wrap all this entries with CONFIG_CHECKPOINT_RESTORE
and say add some sysctl which would enable/disbale this ioctls. Then
it'll be up to user-space callers to make sure that data received is
valid and can be used? The problem is that I need to fetch this bits
somehow with minimal changes in kernel.