Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757728AbZDTVX7 (ORCPT ); Mon, 20 Apr 2009 17:23:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756587AbZDTVXk (ORCPT ); Mon, 20 Apr 2009 17:23:40 -0400 Received: from zcars04e.nortel.com ([47.129.242.56]:55226 "EHLO zcars04e.nortel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756571AbZDTVXi (ORCPT ); Mon, 20 Apr 2009 17:23:38 -0400 Message-ID: <49ECE783.5050704@nortel.com> Date: Mon, 20 Apr 2009 15:22:11 -0600 From: "Chris Friesen" User-Agent: Thunderbird 2.0.0.21 (X11/20090302) MIME-Version: 1.0 To: Linus Torvalds CC: "Rafael J. Wysocki" , Linux Kernel Mailing List , Adrian Bunk , Andrew Morton , Natalie Protasevich , Kernel Testers List , Network Development , Linux ACPI , Linux PM List , Linux SCSI List , Trenton Adams Subject: Re: 2.6.29-git13: Reported regressions from 2.6.28 References: <200904070035.00784.rjw@sisk.pl> <49E79E58.9000606@nortel.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 20 Apr 2009 21:22:13.0741 (UTC) FILETIME=[12C341D0:01C9C1FE] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1649 Lines: 35 Linus Torvalds wrote: > > On Thu, 16 Apr 2009, Chris Friesen wrote: >> I'm okay with that. The problem causes some backwards compatibility problems >> with existing apps that get confused by the large "offset" number. The fix is >> going to cause problems too, but in a different way. >> >> We'll work around it. > > If you have actual apps that care, that's a different issue. > > We do try to bend over backwards on ABI issues if it really is noticeable > for applications. Now, in this case, if you can just fix your app to not > care (because it really was badly written in the first place to even > notice), then that is the _much_ superior solution. Yep, we can fix the app to ignore that field for anonymous mappings. > Although I don't really even see what we can sanely do except for the 0 > case. We could put the virtual address in there instead of zero (I forget > what old kernels used to do - whatever magic value the anonymous mappings > got, it wasn't really designed as an important value in its own right, it > was designed to trigger the "we can merge these vma's" logic. For anonymous mappings, the older kernels put the starting address of the VMA (from the point of view of the app) as the offset. Until the recent change, new kernels still did this for most VMAs, but the stack offset was a 64-bit value with no obvious relation to the VMA start address. Chris -- 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/