Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752878AbcD2WLx (ORCPT ); Fri, 29 Apr 2016 18:11:53 -0400 Received: from mx2.suse.de ([195.135.220.15]:55016 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752761AbcD2WLw (ORCPT ); Fri, 29 Apr 2016 18:11:52 -0400 Date: Sat, 30 Apr 2016 00:11:45 +0200 (CEST) From: Jiri Kosina X-X-Sender: jkosina@pobox.suse.cz To: Andy Lutomirski cc: Josh Poimboeuf , Jessica Yu , Miroslav Benes , Ingo Molnar , Peter Zijlstra , Michael Ellerman , Heiko Carstens , live-patching@vger.kernel.org, "linux-kernel@vger.kernel.org" , X86 ML , linuxppc-dev@lists.ozlabs.org, "linux-s390@vger.kernel.org" , Vojtech Pavlik , Jiri Slaby , Petr Mladek , Chris J Arges , Andy Lutomirski Subject: Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ tracking In-Reply-To: Message-ID: References: <20160429201139.pudoged2yathyo64@treble> <20160429202701.yijrohqdsurdxv2a@treble> <20160429212546.t26mvthtvh7543ff@treble> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 613 Lines: 20 On Fri, 29 Apr 2016, Andy Lutomirski wrote: > > NMI, MCE and interrupts aren't a problem because they have dedicated > > stacks, which are easy to detect. If the tasks' stack is on an > > exception stack or an irq stack, we consider it unreliable. > > Only on x86_64. Well, MCEs are more or less x86-specific as well. But otherwise good point, thanks Andy. So, how does stack layout generally look like in case when NMI is actually running on proper kernel stack? I thought it's guaranteed to contain pt_regs anyway in all cases. Is that not guaranteed to be the case? Thanks, -- Jiri Kosina SUSE Labs