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Date: Sat, 15 Dec 2012 02:43:07 +0400
From: Cyrill Gorcunov <gorcunov@openvz.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>, aarcange@redhat.com,
        ak@linux.intel.com, Pavel Emelyanov <xemul@parallels.com>,
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        linux-kernel@vger.kernel.org, criu@openvz.org, mingo@redhat.com,
        john.stultz@linaro.org, tglx@linutronix.de
Subject: Re: [CRIU] [PATCH] Add VDSO time function support for x86 32-bit
 kernel
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On Fri, Dec 14, 2012 at 02:27:08PM -0800, H. Peter Anvin wrote:
> On 12/14/2012 02:25 PM, Cyrill Gorcunov wrote:
> > 
> > this would allow us to defer checkpoint until task finish vdso code. Peter,
> > if I understand you correctly you propose we provide some own proxy-vdso
> > which would redirect calls to real ones, right? But the main problem
> > is that is exactly the idea to be able to c/r existing programs without
> > recompiling and such (or I miss something here?).
> 
> No, I'm proposing that you use a proxy-vdso which does nothing but
> system calls, and therefore can be stable indefinitely.

This won't help in case of scenario you've been pointing in
previous email (where c/r happens in a middle of vdso),
would it? Because we still need somehow to be sure we're not
checkpointing in a middle of signal handler which will return
to some vdso place.