From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751173AbdIKXme (ORCPT ); Mon, 11 Sep 2017 19:42:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33574 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750911AbdIKXmd (ORCPT ); Mon, 11 Sep 2017 19:42:33 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com EF6B2EA3DB Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=jpoimboe@redhat.com Date: Mon, 11 Sep 2017 18:42:30 -0500 From: Josh Poimboeuf To: Arnd Bergmann Cc: Ingo Molnar , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Kees Cook , linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86/kconfig: hide unwinder menu for KMEMCHECK Message-ID: <20170911234230.wmsd7nkpeckot45m@treble> References: <20170911195950.3077184-1-arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170911195950.3077184-1-arnd@arndb.de> User-Agent: Mutt/1.6.0.1 (2016-04-01) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Mon, 11 Sep 2017 23:42:33 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 11, 2017 at 09:59:36PM +0200, Arnd Bergmann wrote: > When KMEMCHECK is enabled, we always build with frame pointers, > which is incompatible with ORC_UNWINDER and GUESS_UNWINDER, as > Kconfig points out: > > warning: (FAULT_INJECTION_STACKTRACE_FILTER && LATENCYTOP && KMEMCHECK && LOCKDEP && FRAME_POINTER_UNWINDER) selects FRAME_POINTER which has unmet direct dependencies (DEBUG_KERNEL && (CRIS || M68K || FRV || UML || SUPERH || BLACKFIN || MN10300 || METAG) || ARCH_WANT_FRAME_POINTERS || !ORC_UNWINDER && !GUESS_UNWINDER) > > This works around it by making those two unwinders depend on > !KMEMCHECK. The other three options that enable frame pointers > (FAULT_INJECTION_STACKTRACE_FILTER, LATENCYTOP and LOCKDEP) only > do that on some architectures but not on x86. > > It's possible that KMEMCHECK doesn't actually require frame pointers > but only requires some unwinder. If that is the case, we should drop > the 'select FRAME_POINTER' there. KMEMCHECK is currenly used only > on x86. KMEMCHECK should work with *any* of the unwinders because it uses the unwinder-agnostic save_stack_trace() interface. So removing the 'select FRAME_POINTER' sounds like the right fix. -- Josh