From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 22 May 2002 15:33:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 22 May 2002 15:33:37 -0400 Received: from imladris.infradead.org ([194.205.184.45]:57618 "EHLO phoenix.infradead.org") by vger.kernel.org with ESMTP id ; Wed, 22 May 2002 15:33:36 -0400 Date: Wed, 22 May 2002 20:33:28 +0100 From: Christoph Hellwig To: Dan Kegel Cc: Christoph Hellwig , "linux-kernel@vger.kernel.org" , "khttpd-users@lists.alt.org" , "linuxppc-embedded@lists.linuxppc.org" , lord@sgi.com Subject: Re: khttpd and tmpfs don't get along? Message-ID: <20020522203328.A22461@infradead.org> Mail-Followup-To: Christoph Hellwig , Dan Kegel , "linux-kernel@vger.kernel.org" , "khttpd-users@lists.alt.org" , "linuxppc-embedded@lists.linuxppc.org" , lord@sgi.com In-Reply-To: <3CEAF6F2.BB70395D@kegel.com> <20020522095440.A13744@infradead.org> <3CEBEF97.1BEBF36C@kegel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 22, 2002 at 12:20:55PM -0700, Dan Kegel wrote: > I just now crashed Red Hat 7.3 on x86 SMP by compiling in khttpd > and serving files out of a tmpfs. It crashed with or without my > earlier patch (http://www.kegel.com/linux/khttpd/khttpd-unbork.patch) > that fixes khttpd crashes with other filesystems. > Guess it wasn't a bug in linuxppc_2_4_devel after all. I doubt it. the use of do_generic_file_read outside of code the filesystem has selected to use (i.e. generic methods) is FUNDAMENTALLY broken. Some time ago I though I found a similar bug in XFS, but Steve Lord says it's not exploitable in real world (XFS uses the generic methods with additional locking around it). The only sane soloution is to get rid of that abuse in khttpd, loop and sys_sendfile.