Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754495Ab1FMIpR (ORCPT ); Mon, 13 Jun 2011 04:45:17 -0400 Received: from mail-yw0-f46.google.com ([209.85.213.46]:40246 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753722Ab1FMIpP convert rfc822-to-8bit (ORCPT ); Mon, 13 Jun 2011 04:45:15 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=VL75/V9Zz5tUy4SJZA7VXY2Pey+HtScPB9MNCA96samTP8V3dq3P2ELXOk7wB3R5/3 ZfzLFhEJBYXCgksOerycBPMmdFk3dxpMb1l+Kks4Qwr8ceMm/5o2YFgWS/mSFtkyh9Kc v6ptf7TMjvjGVE40iJ7ZQkkUoFi2ppuukwh/k= MIME-Version: 1.0 In-Reply-To: References: <1307777464.25182.3.camel@localhost.localdomain> Date: Mon, 13 Jun 2011 14:45:14 +0600 Message-ID: Subject: Re: [PATCH] x86, vsyscall: Fix build warning in vsyscall_64.c From: Rakib Mullick To: Andrew Lutomirski Cc: mingo@elte.hu, hpa@zytor.com, tglx@linutronix.de, x86@kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1622 Lines: 35 On Mon, Jun 13, 2011 at 10:54 AM, Rakib Mullick wrote: > On Mon, Jun 13, 2011 at 8:52 AM, Andrew Lutomirski wrote: >> On Sun, Jun 12, 2011 at 1:12 AM, Rakib Mullick wrote: >>> On Sat, Jun 11, 2011 at 5:01 PM, Andrew Lutomirski wrote: >>>> On Sat, Jun 11, 2011 at 3:31 AM, Rakib Mullick wrote: >> >> I think there are three separate issues here: >> >> 1. Can ret be used uninitialized? ?I say no, even as seen by the >> compiler. ?If vsyscall_nr is 0, 1, or 2, then ret is initialized. ?If >> vsyscall_nr is 3, then the BUG gets hit. ?BUG is defined as some >> assembly magic followed by unreachable(), and the compiler is supposed >> to know that code after unreachable() is qunreachable. ?So how can ret >> be used uninitialized? >> > I don't have much knowledge of advance assembly, so I really don't > understand that part - how BUG handles this. If it really makes sure > that, it will handle it properly then I think you can drop this patch. > >> What version of gcc do you have? ?gcc (GCC) 4.6.0 20110530 (Red Hat >> 4.6.0-9) does not produce this warning. >> > Currently, I'm replying from outside my home. I'll let you know when > I'm back home. > Here is my GCC version - gcc version 4.5.1 20100924 (Red Hat 4.5.1-4) (GCC). I'm using Fedora 14. Thanks, Rakib -- 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/