From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754196Ab2BUEwp (ORCPT ); Mon, 20 Feb 2012 23:52:45 -0500 Received: from out5-smtp.messagingengine.com ([66.111.4.29]:37912 "EHLO out5-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752666Ab2BUEwo (ORCPT ); Mon, 20 Feb 2012 23:52:44 -0500 X-Sasl-enc: BPvLOfDEcAoxvd4O/yyNdQvVYAPOqhfyV9/43Th9ytIB5dUj0WQQrCKx4A 1329799963 Message-ID: <1329799959.2226.32.camel@perseus.themaw.net> Subject: Re: Linux 3.3-rc4 From: Ian Kent To: Linus Torvalds Cc: David Miller , thomas@m3y3r.de, linux-kernel@vger.kernel.org, "H. Peter Anvin" Date: Tue, 21 Feb 2012 12:52:39 +0800 In-Reply-To: References: <20120219.144947.660678318380307878.davem@davemloft.net> <1329794974.2226.11.camel@perseus.themaw.net> <1329796956.2226.20.camel@perseus.themaw.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 (3.2.3-1.fc16) Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2012-02-20 at 20:17 -0800, Linus Torvalds wrote: > On Mon, Feb 20, 2012 at 8:02 PM, Ian Kent wrote: > > > > It doesn't but changing it for exiting binaries will break existing > > binaries that use a workaround. > > What existing binaries? My bad, autofs for one, but obviously when running in compat mode. And any other user space users, such as the auto_dir package, but I don't know if that is maintained any more. > > > I'm proposing this because the systemd folks were happy to do it this > > way. But if you would like any other existing user space users to change > > to using a correctly sized packet then, yes, it isn't what you want to > > happen. > > Existing binaries *do* use the correct size packet - it's the correct > size for native x86-32! > > It's our x86-64 compat layer that is wrong. It's a clear bug. Nothing else. > > We don't start making up new interfaces because we have clear bugs: we > fix the damn bugs. > > How could you even sanely do "workarounds"? A x86-32 binary shouldn't > even be able to *tell* that the kernel is 64-bit. And if it does that > somehow, we should fix that too! Sure, not an acceptable excuse I know, but it was too late when I realized my mistake. So, as you say, let's fix the bug. autofs is by far the biggest user and I can manage the change for it and I can at least post to the auto_dir list (if it still exists) and Thomas can feedback to the systemd folks. Then there is the question of how it should be done. I think the patch attached to your original post needs a little work if that is to be used. Correct me if I'm wrong but AFAICT there are more architectures that use 8-byte alignment than just x86-64, such as alpha, ia64 and ppc64 and I believe they may also be used in a compat mode. Is there a better way to do this change, anyone? Ian