From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761581AbZEOJdl (ORCPT ); Fri, 15 May 2009 05:33:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759409AbZEOJdM (ORCPT ); Fri, 15 May 2009 05:33:12 -0400 Received: from one.firstfloor.org ([213.235.205.2]:50345 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757979AbZEOJdJ (ORCPT ); Fri, 15 May 2009 05:33:09 -0400 Date: Fri, 15 May 2009 11:38:38 +0200 From: Andi Kleen To: Vitaly Mayatskikh Cc: Andi Kleen , Josef Bacik , sandeen@redhat.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] Perform check in iov_iter_fault_in_readable() by check_readable_bytes() Message-ID: <20090515093838.GB16682@one.firstfloor.org> References: <1242317939-15392-1-git-send-email-v.mayatskih@gmail.com> <1242317939-15392-3-git-send-email-v.mayatskih@gmail.com> <87k54iq2gv.fsf@basil.nowhere.org> <871vqqkdf0.wl%vmayatsk@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <871vqqkdf0.wl%vmayatsk@redhat.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > ptr = mmap(0, page_size, ....); > ... > write(fd, ptr + page_size - 256, 512); > > Write() will fail here, but it can write first 256 bytes. Previously, > all 512 bytes were proceeded, but last 256 bytes were zeroed, and > sys_write() returned 256. Not very nice too. Is that really something that users rely on? It looks like a seriously broken user program. Which one is that? (just that I can avoid it :) -Andi -- ak@linux.intel.com -- Speaking for myself only.