From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758384Ab2CFHu0 (ORCPT ); Tue, 6 Mar 2012 02:50:26 -0500 Received: from nat28.tlf.novell.com ([130.57.49.28]:32860 "EHLO nat28.tlf.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756795Ab2CFHuZ convert rfc822-to-8bit (ORCPT ); Tue, 6 Mar 2012 02:50:25 -0500 Message-Id: <4F55CFCD02000078000768ED@nat28.tlf.novell.com> X-Mailer: Novell GroupWise Internet Agent 12.0.0 Date: Tue, 06 Mar 2012 07:50:21 +0000 From: "Jan Beulich" To: "Joe Perches" Cc: , "Linus Torvalds" , Subject: Re: [PATCH] vsprintf: make %pV handling compatible with kasprintf() References: <4F54FCA402000078000766F1@nat28.tlf.novell.com> <1330966942.3140.8.camel@joe2Laptop> In-Reply-To: <1330966942.3140.8.camel@joe2Laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> On 05.03.12 at 18:02, Joe Perches wrote: > On Mon, 2012-03-05 at 16:49 +0000, Jan Beulich wrote: >> kasprintf() (and potentially other functions that I didn't run across >> so far) want to evaluate argument lists twice. Caring to do so for the >> primary list is obviously their job, but they can't reasonably be >> expected to check the format string for instances of %pV, which however >> need special handling too: On architectures like x86-64 (as opposed to >> e.g. ix86), using the same argument list twice doesn't produce the >> expected results, as an internally managed cursor gets updated during >> the first run. >> >> Fix the problem by always acting on a copy of the original list when >> handling %pV. > > Wouldn't stable need this too? Possibly, but I'm not certain - this is more of a latent bug that I ran into with some not yet submitted Xen code. And I'm not sure whether latent bugs qualify for stable... Jan