Date: Fri, 23 Nov 2012 18:42:56 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Pavel Emelyanov <xemul@parallels.com>
Cc: Amnon Shiloh <u3557@miso.sublimeip.com>,
        Cyrill Gorcunov <gorcunov@openvz.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>, linux-kernel@vger.kernel.org
Subject: Re: vdso && cr (Was: arch_check_bp_in_kernelspace: fix the range
	check)
Message-ID: <20121123174256.GA3361@redhat.com>
References: <20121121141627.GB21030@redhat.com> <20121121173043.F0319592076@miso.sublimeip.com> <20121122161238.GA27078@redhat.com> <50AE91AD.1090709@parallels.com>
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On 11/23, Pavel Emelyanov wrote:
>
> On 11/22/2012 08:12 PM, Oleg Nesterov wrote:
>
> > Sure. You shouldn't try to save/restore this page(s) directly. But
> > I do not really understand why do you need. IOW, I don't really
> > understand the problem, it depends on what c/r actually does.
>
> Think about it like this -- you stop a process, then change the kern^w VDSO
> page. Everything should work as it used to be :)

I understand. But again, this depends on how you restore. For example,
if you do not "transfer" libc/ld code, then probably vdso is not a
problem. Just you need to ensure the task was not stopped "inside" vdso.
Yes, yes, I understand that this is too limited, you probably want to
transfer "everything".

Oleg.

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