Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261833AbVBIPes (ORCPT ); Wed, 9 Feb 2005 10:34:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261835AbVBIPes (ORCPT ); Wed, 9 Feb 2005 10:34:48 -0500 Received: from nevyn.them.org ([66.93.172.17]:4225 "EHLO nevyn.them.org") by vger.kernel.org with ESMTP id S261833AbVBIPeq (ORCPT ); Wed, 9 Feb 2005 10:34:46 -0500 Date: Wed, 9 Feb 2005 10:34:41 -0500 From: Daniel Jacobowitz To: Andrew Morton Cc: Stephen Hemminger , linux-kernel@vger.kernel.org, Pavel Machek Subject: Re: 2.6.11-rc3: Kylix application no longer works? Message-ID: <20050209153441.GA8809@nevyn.them.org> Mail-Followup-To: Andrew Morton , Stephen Hemminger , linux-kernel@vger.kernel.org, Pavel Machek References: <20050207221107.GA1369@elf.ucw.cz> <20050207145100.6208b8b9.akpm@osdl.org> <20050208175106.GA1091@elf.ucw.cz> <20050208111625.0bb1896d@dxpl.pdx.osdl.net> <20050208181018.5592beab.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050208181018.5592beab.akpm@osdl.org> User-Agent: Mutt/1.5.6+20040907i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1400 Lines: 33 On Tue, Feb 08, 2005 at 06:10:18PM -0800, Andrew Morton wrote: > We could just remove the printk and stick a comment over it. If the > application later tries to access the not-there pages then it'll just > fault. > > However I worry if there is some way in which we can leave unzeroed memory > accessible to the application, although it's hard to see how that could > happen. > > Daniel, Pavel cruelly chopped you off the Cc when replying. What's your > diagnosis on the below? It's asking for a lot of unwritable zeroed space. See this: > LOAD 0x000000 0x08048000 0x08048000 0xb7354 0x1b7354 R E 0x1000 > LOAD 0x0b7354 0x08200354 0x08200354 0x1e3e4 0x1f648 RW 0x1000 The 0xb7354 is size to map from the file, the 0x1b7354 is size to map in memory. We're supposed to zero-fill the rest. Now that I think about it I can see why this is a problem - the kernel probably assumes that any segment with MemSiz > FileSiz will be writable. Certainly it's a bit weird for the app to request unwritable zeroed pages. clear_user's probably not the right way to provide the extra zeroing. -- Daniel Jacobowitz CodeSourcery, LLC - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/