From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [PATCH] [8/18] BKL-removal: Remove BKL from remote_llseek Date: Mon, 28 Jan 2008 05:38:25 +0100 Message-ID: <200801280538.25345.ak@suse.de> References: <20080127317.043953000@suse.de> <200801280358.14024.ak@suse.de> <1201493589.8132.7.camel@heimdal.trondhjem.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Cc: Steve French , swhiteho@redhat.com, sfrench@samba.org, vandrove@vc.cvut.cz, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, akpm@osdl.org To: Trond Myklebust Return-path: Received: from ns2.suse.de ([195.135.220.15]:56413 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751995AbYA1Ei3 (ORCPT ); Sun, 27 Jan 2008 23:38:29 -0500 In-Reply-To: <1201493589.8132.7.camel@heimdal.trondhjem.org> Content-Disposition: inline Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Monday 28 January 2008 05:13:09 Trond Myklebust wrote: > > On Mon, 2008-01-28 at 03:58 +0100, Andi Kleen wrote: > > The problem is that it's not a race in who gets to do its thing first, but a > > parallel reader can actually see a corrupted value from the two independent > > words on 32bit (e.g. during a 4GB). And this could actually completely corrupt > > f_pos when it happens with two racing relative seeks or read/write()s > > > > I would consider that a bug. > > I disagree. The corruption occurs because this isn't a situation that is > allowed by either POSIX or SUSv2/v3. Exactly what spec are you referring > to here? No specific spec, just general quality of implementation. We normally don't have non thread safe system calls even if it was in theory allowed by some specification. -Andi