From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753423AbZEJLpo (ORCPT ); Sun, 10 May 2009 07:45:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751513AbZEJLpY (ORCPT ); Sun, 10 May 2009 07:45:24 -0400 Received: from mail-gx0-f166.google.com ([209.85.217.166]:47508 "EHLO mail-gx0-f166.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751173AbZEJLpT (ORCPT ); Sun, 10 May 2009 07:45:19 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=gcWmIhP3CjEO81sp2pyA0aIH4tbytL7o/bHiPsObck43VoiS2dJ5SGfwRD+byGRuGl mIfFUFsAU/UWwpBdI6H/E8nQZuaOD6pyCCwItRhI49T0pfPgvlxq59BSAMvEpiE8IIXp YDBjt35E5+68fjb2IDYf2mltJARbagCXlG0rc= MIME-Version: 1.0 In-Reply-To: <20090510112149.GA8633@localhost> References: <20090507151039.GA2413@cmpxchg.org> <20090508081608.GA25117@localhost> <20090508125859.210a2a25.akpm@linux-foundation.org> <20090508230045.5346bd32@lxorguk.ukuu.org.uk> <2f11576a0905100159m32c36a9ep9fb7cc5604c60b2@mail.gmail.com> <20090510092053.GA7651@localhost> <2f11576a0905100229m2c5e6a67md555191dc8c374ae@mail.gmail.com> <20090510100335.GC7651@localhost> <2f11576a0905100315j2c810e96mc29b84647dc565c2@mail.gmail.com> <20090510112149.GA8633@localhost> Date: Sun, 10 May 2009 20:39:12 +0900 X-Google-Sender-Auth: c81013be17f414b4 Message-ID: <2f11576a0905100439u38c8bccak355ec23953950d6@mail.gmail.com> Subject: Re: [PATCH -mm] vmscan: make mapped executable pages the first class citizen From: KOSAKI Motohiro To: Wu Fengguang Cc: Alan Cox , Andrew Morton , "hannes@cmpxchg.org" , "peterz@infradead.org" , "riel@redhat.com" , "linux-kernel@vger.kernel.org" , "tytso@mit.edu" , "linux-mm@kvack.org" , "elladan@eskimo.com" , "npiggin@suse.de" , "cl@linux-foundation.org" , "minchan.kim@gmail.com" 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 >> > So if that's what they want, let them have it to their heart's content. >> > >> > You know it's normal for many users/apps to care only about the result. >> > When they want something but cannot get it from the smarter version of >> > PROT_EXEC heuristics, they will go on to devise more complicated tricks. >> > >> > In the end both sides loose. >> > >> > If the abused case is important enough, then let's introduce a feature >> > to explicitly prioritize the pages. But let's leave the PROT_EXEC case >> > simple. >> >> No. >> explicit priotize mechanism don't solve problem anyway. application >> developer don't know end-user environment. >> they can't mark proper page priority. > > So it's simply wrong for an application to prioritize itself and is > not fair gaming and hence should be blamed. I doubt any application > aimed for a wide audience will do this insane hack. There already are. some application don't interest strict PROT_ setting. They always use mmap(PROT_READ | PROT_WRITE | PROT_EXEC) for anycase. Please google it. you can find various example. > But specific > targeted applications are more likely to do all tricks which fits > their needs&environment, and likely they are doing so for good reasons > and are aware of the consequences. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id B5EDB6B0089 for ; Sun, 10 May 2009 07:38:36 -0400 (EDT) Received: by yx-out-1718.google.com with SMTP id 36so1203162yxh.26 for ; Sun, 10 May 2009 04:39:12 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20090510112149.GA8633@localhost> References: <20090507151039.GA2413@cmpxchg.org> <20090508081608.GA25117@localhost> <20090508125859.210a2a25.akpm@linux-foundation.org> <20090508230045.5346bd32@lxorguk.ukuu.org.uk> <2f11576a0905100159m32c36a9ep9fb7cc5604c60b2@mail.gmail.com> <20090510092053.GA7651@localhost> <2f11576a0905100229m2c5e6a67md555191dc8c374ae@mail.gmail.com> <20090510100335.GC7651@localhost> <2f11576a0905100315j2c810e96mc29b84647dc565c2@mail.gmail.com> <20090510112149.GA8633@localhost> Date: Sun, 10 May 2009 20:39:12 +0900 Message-ID: <2f11576a0905100439u38c8bccak355ec23953950d6@mail.gmail.com> Subject: Re: [PATCH -mm] vmscan: make mapped executable pages the first class citizen From: KOSAKI Motohiro Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: Alan Cox , Andrew Morton , "hannes@cmpxchg.org" , "peterz@infradead.org" , "riel@redhat.com" , "linux-kernel@vger.kernel.org" , "tytso@mit.edu" , "linux-mm@kvack.org" , "elladan@eskimo.com" , "npiggin@suse.de" , "cl@linux-foundation.org" , "minchan.kim@gmail.com" List-ID: >> > So if that's what they want, let them have it to their heart's content. >> > >> > You know it's normal for many users/apps to care only about the result. >> > When they want something but cannot get it from the smarter version of >> > PROT_EXEC heuristics, they will go on to devise more complicated tricks. >> > >> > In the end both sides loose. >> > >> > If the abused case is important enough, then let's introduce a feature >> > to explicitly prioritize the pages. But let's leave the PROT_EXEC case >> > simple. >> >> No. >> explicit priotize mechanism don't solve problem anyway. application >> developer don't know end-user environment. >> they can't mark proper page priority. > > So it's simply wrong for an application to prioritize itself and is > not fair gaming and hence should be blamed. I doubt any application > aimed for a wide audience will do this insane hack. There already are. some application don't interest strict PROT_ setting. They always use mmap(PROT_READ | PROT_WRITE | PROT_EXEC) for anycase. Please google it. you can find various example. > But specific > targeted applications are more likely to do all tricks which fits > their needs&environment, and likely they are doing so for good reasons > and are aware of the consequences. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org