From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751674AbaETSSp (ORCPT ); Tue, 20 May 2014 14:18:45 -0400 Received: from terminus.zytor.com ([198.137.202.10]:52904 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750835AbaETSSo (ORCPT ); Tue, 20 May 2014 14:18:44 -0400 Message-ID: <537B9C6D.7010705@zytor.com> Date: Tue, 20 May 2014 11:18:21 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Cyrill Gorcunov , Andy Lutomirski CC: X86 ML , Andrew Morton , Sasha Levin , "linux-mm@kvack.org" , Dave Jones , LKML , Pavel Emelyanov Subject: Re: [PATCH 3/4] x86,mm: Improve _install_special_mapping and fix x86 vdso naming References: <276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net> <20140520172134.GJ2185@moon> <20140520174759.GK2185@moon> <20140520180104.GL2185@moon> In-Reply-To: <20140520180104.GL2185@moon> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/20/2014 11:01 AM, Cyrill Gorcunov wrote: >> >> This patch should fix this issue, at least. If there's still a way to >> get a native vdso that doesn't say "[vdso]", please let me know/ > > Yes, having a native procfs way to detect vdso is much preferred! > Is there any path by which we can end up with [vdso] without a leading slash in /proc/self/maps? Otherwise, why is that not "native"? >>> The situation get worse when task was dumped on one kernel and >>> then restored on another kernel where vdso content is different >>> from one save in image -- is such case as I mentioned we need >>> that named vdso proxy which redirect calls to vdso of the system >>> where task is restoring. And when such "restored" task get checkpointed >>> second time we don't dump new living vdso but save only old vdso >>> proxy on disk (detecting it is a different story, in short we >>> inject a unique mark into elf header). >> >> Yuck. But I don't know whether the kernel can help much here. > > Some prctl which would tell kernel to put vdso at specifed address. > We can live without it for now so not a big deal (yet ;) mremap() will do this for you. -hpa