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From: "H. Peter Anvin" <hpa@zytor.com>
To: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
	aarcange@redhat.com, ak@linux.intel.com,
	Pavel Emelyanov <xemul@parallels.com>,
	Stefani Seibold <stefani@seibold.net>,
	x86@kernel.org, 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
Date: Fri, 14 Dec 2012 13:08:35 -0800	[thread overview]
Message-ID: <50CB9553.7050808@zytor.com> (raw)
In-Reply-To: <20121214201217.GE6582@moon>

On 12/14/2012 12:12 PM, Cyrill Gorcunov wrote:
>>>
>> The real issue is that happens if the process is checkpointed while
>> inside the vdso and now eip/rip or a stack frame points into the vdso.
>> This is not impossible or even unlikely, especially on 32 bits it is
>> downright likely.
> 
> I fear if there are stacked ip which point to vdso -- we simply won't
> be able to restore properly if vdso internal format changed significantly
> between kernel versions. (At moment we restore vdso exactly at same position
> it was on checkpoint stage with same content, iirc).
> 

I don't think there is a way around that.  It is completely unreasonable
to say that the vdso cannot change between kernel versions, for obvious
reasons.  It's worse than "significantly"... changing even one
instruction makes it plausible your eip/rip will point into the middle
of an instruction.

	-hpa



  reply	other threads:[~2012-12-14 21:09 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-12 20:19 [PATCH] Add VDSO time function support for x86 32-bit kernel stefani
2012-12-12 23:34 ` H. Peter Anvin
2012-12-13  5:53   ` Stefani Seibold
2012-12-13  6:10     ` H. Peter Anvin
2012-12-13  6:14     ` H. Peter Anvin
2012-12-13  6:17       ` Stefani Seibold
2012-12-13  6:47         ` H. Peter Anvin
2012-12-13  7:17           ` Stefani Seibold
2012-12-13 19:32             ` Andy Lutomirski
2012-12-14  0:09               ` H. Peter Anvin
2012-12-14  0:20                 ` Andy Lutomirski
2012-12-14  0:36                   ` H. Peter Anvin
2012-12-14  1:32                   ` H. Peter Anvin
2012-12-14  1:42                     ` Andy Lutomirski
2012-12-14  1:49                       ` H. Peter Anvin
2012-12-14  2:11                         ` Andy Lutomirski
2012-12-14  2:18                           ` H. Peter Anvin
2012-12-14  2:20                             ` Andy Lutomirski
2012-12-14  8:34                               ` [CRIU] " Pavel Emelyanov
2012-12-14 18:35                                 ` H. Peter Anvin
2012-12-14 18:44                                   ` Andy Lutomirski
2012-12-14 18:47                                     ` H. Peter Anvin
2012-12-14 20:12                                       ` Cyrill Gorcunov
2012-12-14 21:08                                         ` H. Peter Anvin [this message]
2012-12-14 21:20                                           ` Cyrill Gorcunov
2012-12-14 21:21                                             ` H. Peter Anvin
2012-12-14 21:27                                           ` Andy Lutomirski
2012-12-14 22:00                                             ` H. Peter Anvin
2012-12-14 22:25                                               ` Cyrill Gorcunov
2012-12-14 22:27                                                 ` H. Peter Anvin
2012-12-14 22:43                                                   ` Cyrill Gorcunov
2012-12-14 22:48                                                     ` H. Peter Anvin
2012-12-14 23:48                                                       ` John Stultz
2012-12-14 23:55                                                         ` H. Peter Anvin
2012-12-17  9:05                                     ` Pavel Emelyanov
     [not found]                                       ` <fb2e871b-3e2a-4e96-9eb9-cb2dd4f66eaa@email.android! .com>
2012-12-17 15:21                                       ` H. Peter Anvin
2012-12-17 18:56                                         ` Pavel Emelyanov
2012-12-17 18:57                                           ` H. Peter Anvin
2012-12-14 22:46                                 ` H. Peter Anvin
2012-12-14 23:09                                   ` Stefani Seibold
2012-12-14 23:29                                     ` H. Peter Anvin

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