From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A74F7C433FF for ; Sun, 28 Jul 2019 20:31:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7CBE120657 for ; Sun, 28 Jul 2019 20:31:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726404AbfG1UbA (ORCPT ); Sun, 28 Jul 2019 16:31:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50608 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726129AbfG1UbA (ORCPT ); Sun, 28 Jul 2019 16:31:00 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DA90D3B551; Sun, 28 Jul 2019 20:30:59 +0000 (UTC) Received: from treble (ovpn-120-102.rdu2.redhat.com [10.10.120.102]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0705C5D70D; Sun, 28 Jul 2019 20:30:55 +0000 (UTC) Date: Sun, 28 Jul 2019 15:30:53 -0500 From: Josh Poimboeuf To: Miroslav Benes Cc: Joe Lawrence , heiko.carstens@de.ibm.com, gor@linux.ibm.com, borntraeger@de.ibm.com, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, jikos@kernel.org, pmladek@suse.com, nstange@suse.de, live-patching@vger.kernel.org Subject: Re: [PATCH] s390/livepatch: Implement reliable stack tracing for the consistency model Message-ID: <20190728203053.q3pafkwnzm5j3ccs@treble> References: <20190710105918.22487-1-mbenes@suse.cz> <20190716184549.GA26084@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Sun, 28 Jul 2019 20:31:00 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 17, 2019 at 01:01:27PM +0200, Miroslav Benes wrote: > > On a related note, do you think it would be feasible to extend (in > > another patchset) the reliable stack unwinding code a bit so that we > > could feed it pre-baked stacks ... then we could verify that the code > > was finding interesting scenarios. That was a passing thought I had > > back when Nicolai and I were debugging the ppc64le exception frame > > marker bug, but didn't think it worth the time/effort at the time. > > That is an interesting thought. It would help the testing a lot. I will > make a note in my todo list. Another idea I had for reliable unwinder testing: add a CONFIG_RELIABLE_STACKTRACE_DEBUG option which does a periodic stack trace and warns if it doesn't reach the end. It could triggered from a periodic NMI, or from schedule(). -- Josh