From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752772AbdHJNGw (ORCPT ); Thu, 10 Aug 2017 09:06:52 -0400 Received: from mx2.suse.de ([195.135.220.15]:44467 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752227AbdHJNGt (ORCPT ); Thu, 10 Aug 2017 09:06:49 -0400 Date: Thu, 10 Aug 2017 15:06:45 +0200 From: Michal Hocko To: Florian Weimer Cc: riel@redhat.com, linux-kernel@vger.kernel.org, mike.kravetz@oracle.com, linux-mm@kvack.org, colm@allcosts.net, akpm@linux-foundation.org, keescook@chromium.org, luto@amacapital.net, wad@chromium.org, mingo@kernel.org, kirill@shutemov.name, dave.hansen@intel.com, linux-api@vger.kernel.org Subject: Re: [PATCH v2 0/2] mm,fork,security: introduce MADV_WIPEONFORK Message-ID: <20170810130645.GT23863@dhcp22.suse.cz> References: <20170806140425.20937-1-riel@redhat.com> <20170807132257.GH32434@dhcp22.suse.cz> <20170807134648.GI32434@dhcp22.suse.cz> <134bbcf4-5717-7f53-0bf1-57158e948bbe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <134bbcf4-5717-7f53-0bf1-57158e948bbe@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 07-08-17 16:19:18, Florian Weimer wrote: > On 08/07/2017 03:46 PM, Michal Hocko wrote: > > How do they know that they need to regenerate if they do not get SEGV? > > Are they going to assume that a read of zeros is a "must init again"? Isn't > > that too fragile? > > Why would it be fragile? Some level of synchronization is needed to set > things up, of course, but I think it's possible to write a lock-free > algorithm to maintain the state even without strong guarantees of memory > ordering from fork. Yeah, that is what I meant as fragile... I am not question this is impossible. -- Michal Hocko SUSE Labs