From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264922AbUEQHZm (ORCPT ); Mon, 17 May 2004 03:25:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264928AbUEQHZm (ORCPT ); Mon, 17 May 2004 03:25:42 -0400 Received: from fw.osdl.org ([65.172.181.6]:56301 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S264922AbUEQHZk (ORCPT ); Mon, 17 May 2004 03:25:40 -0400 Date: Mon, 17 May 2004 00:25:06 -0700 From: Andrew Morton To: Linus Torvalds Cc: elenstev@mesatop.com, lm@bitmover.com, wli@holomorphy.com, hugh@veritas.com, adi@bitmover.com, scole@lanl.gov, support@bitmover.com, linux-kernel@vger.kernel.org Subject: Re: 1352 NUL bytes at the end of a page? (was Re: Assertion `s && s->tree' failed: The saga continues.) Message-Id: <20040517002506.34022cb8.akpm@osdl.org> In-Reply-To: References: <200405132232.01484.elenstev@mesatop.com> <20040517022816.GA14939@work.bitmover.com> <200405162136.24441.elenstev@mesatop.com> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Linus Torvalds wrote: > > Andrew, the obvious culprit would be the memset() in fs/buffer.c > (block_write_full_page() There is one race. If an application does mmap(MAP_SHARED) of, say, a 2048 byte file and then extends it: p = mmap(..., fd, ...); ftructate(fd, 4096); p[3000] = 1; A racing block_write_full_page() could fail to notice the extended i_size and would decide to zap those 2048 bytes anyway.