From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751296AbaKJSKF (ORCPT ); Mon, 10 Nov 2014 13:10:05 -0500 Received: from mail-vc0-f174.google.com ([209.85.220.174]:44961 "EHLO mail-vc0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750829AbaKJSKC (ORCPT ); Mon, 10 Nov 2014 13:10:02 -0500 MIME-Version: 1.0 In-Reply-To: References: <5458A9600200007800044AE5@mail.emea.novell.com> <20141110100117.GA15841@gmail.com> Date: Mon, 10 Nov 2014 10:10:01 -0800 X-Google-Sender-Auth: er0CCMPy4TT9fPC95NOIY28G9Bw Message-ID: Subject: Re: [PATCH, RFC] x86: also CFI-annotate certain inline asm()s From: Linus Torvalds To: Ingo Molnar Cc: Peter Anvin , Jan Beulich , Thomas Gleixner , Ingo Molnar , Linux Kernel Mailing List , Tony Jones Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 10, 2014 at 9:56 AM, Linus Torvalds wrote: > > So no. A very strong NACK. The code was too ugly to live, there is no good > stated reason for it, and the only reason I can even remotely imagine is > wrong and complete crap anyway (ie making the CFI annotations a correctness > issue by introducing other infrastructure that depends on it always being > right). Btw, the sane thing to do is to make your infrastructure just say "If my frame walker hits a push/pop without CFI information, I'll just add it myself". Yes, that involved having to actuall ylook at the instruction. Tough shit. Just do it right. There aren't that many push/pop patterns. Don't make the kernel more fragile by introducing these kinds of hacky macros-from-hell. Improve the debugger, don't make kernel code worse because your out-of-tree debugging infrastructure is too broken to live. Linus