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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham 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 B5DD4C169C4 for ; Tue, 29 Jan 2019 21:10:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78FB920881 for ; Tue, 29 Jan 2019 21:10:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729586AbfA2VKO (ORCPT ); Tue, 29 Jan 2019 16:10:14 -0500 Received: from mx1.redhat.com ([209.132.183.28]:2599 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727322AbfA2VKN (ORCPT ); Tue, 29 Jan 2019 16:10:13 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 51A35804F4; Tue, 29 Jan 2019 21:10:13 +0000 (UTC) Received: from treble (ovpn-120-147.rdu2.redhat.com [10.10.120.147]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 20248BAA0; Tue, 29 Jan 2019 21:10:02 +0000 (UTC) Date: Tue, 29 Jan 2019 15:10:01 -0600 From: Josh Poimboeuf To: Joe Lawrence Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, live-patching@vger.kernel.org, Balbir Singh , Jiri Kosina , Michael Ellerman , Nicolai Stange , Torsten Duwe Subject: Re: [PATCH 0/4] powerpc/livepatch: reliable stack unwinder fixes Message-ID: <20190129211001.fsmxhasid4mamlea@treble> References: <20190122155724.27557-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190122155724.27557-1-joe.lawrence@redhat.com> User-Agent: NeoMutt/20180716 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Tue, 29 Jan 2019 21:10:13 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 22, 2019 at 10:57:20AM -0500, Joe Lawrence wrote: > This patchset fixes a false negative report (ie, unreliable) from the > ppc64 reliable stack unwinder, discussed here [1] when it may > inadvertently trip over a stale exception marker left on the stack. > > The first two patches fix this bug. Nicolai's change clears the marker > from the stack when an exception is finished. The next patch modifies > the unwinder to only look for such on stack elements when the ABI > guarantees that they will actually be initialized. > > The final two patches consist of code cleanups that Nicolai and I > spotted during the development of the fixes. > > Testing included re-running the original test scenario (loading a > livepatch module on ppc64le) on a 5.0.0-rc2 kernel as well as a RHEL-7 > backport. I ran internal tests on the RHEL-7 backport and no new test > failures were introduced. I believe that Nicolai has done the same > with respect to the first patch. > > [1] https://lore.kernel.org/lkml/7f468285-b149-37e2-e782-c9e538b997a9@redhat.com/ > > Joe Lawrence (3): > powerpc/livepatch: relax reliable stack tracer checks for first-frame > powerpc/livepatch: small cleanups in save_stack_trace_tsk_reliable() > powerpc/livepatch: return -ERRNO values in > save_stack_trace_tsk_reliable() > > Nicolai Stange (1): > powerpc/64s: Clear on-stack exception marker upon exception return > > arch/powerpc/Kconfig | 2 +- > arch/powerpc/kernel/entry_64.S | 7 +++ > arch/powerpc/kernel/stacktrace.c | 74 +++++++++++++++++--------------- > 3 files changed, 47 insertions(+), 36 deletions(-) Reviewed-by: Josh Poimboeuf -- Josh