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=-0.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 643DDC04EB8 for ; Mon, 10 Dec 2018 20:31:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2DA7C20672 for ; Mon, 10 Dec 2018 20:31:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2DA7C20672 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728949AbeLJUb5 (ORCPT ); Mon, 10 Dec 2018 15:31:57 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:36182 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727494AbeLJUb5 (ORCPT ); Mon, 10 Dec 2018 15:31:57 -0500 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wBAKScpR138822 for ; Mon, 10 Dec 2018 15:31:56 -0500 Received: from e31.co.us.ibm.com (e31.co.us.ibm.com [32.97.110.149]) by mx0a-001b2d01.pphosted.com with ESMTP id 2p9v1t16da-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 10 Dec 2018 15:31:55 -0500 Received: from localhost by e31.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 10 Dec 2018 20:31:51 -0000 Received: from b03ledav004.gho.boulder.ibm.com (b03ledav004.gho.boulder.ibm.com [9.17.130.235]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id wBAKVoUP30081044 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 10 Dec 2018 20:31:50 GMT Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 88BEF7805E; Mon, 10 Dec 2018 20:31:50 +0000 (GMT) Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0C2007805F; Mon, 10 Dec 2018 20:31:47 +0000 (GMT) Received: from morokweng.localdomain (unknown [9.85.129.222]) by b03ledav004.gho.boulder.ibm.com (Postfix) with ESMTPS; Mon, 10 Dec 2018 20:31:47 +0000 (GMT) References: <1544095908-2414-1-git-send-email-ego@linux.vnet.ibm.com> <87a7li5zv2.fsf@morokweng.localdomain> <20181207104311.GA11431@in.ibm.com> <20181207120346.GB11431@in.ibm.com> <87va443fm3.fsf@morokweng.localdomain> <06dfb955-6af9-ae23-3919-9bee447cfcdc@linux.vnet.ibm.com> User-agent: mu4e 1.0; emacs 26.1 From: Thiago Jung Bauermann To: Michael Bringmann Cc: ego@linux.vnet.ibm.com, Michael Ellerman , Nicholas Piggin , Tyrel Datwyler , Benjamin Herrenschmidt , Vaidyanathan Srinivasan , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] pseries/hotplug: Add more delay in pseries_cpu_die while waiting for rtas-stop In-reply-to: <06dfb955-6af9-ae23-3919-9bee447cfcdc@linux.vnet.ibm.com> Date: Mon, 10 Dec 2018 18:31:43 -0200 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 x-cbid: 18121020-8235-0000-0000-00000E369D28 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010209; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000270; SDB=6.01129878; UDB=6.00587072; IPR=6.00910011; MB=3.00024645; MTD=3.00000008; XFM=3.00000015; UTC=2018-12-10 20:31:53 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18121020-8236-0000-0000-000043A83019 Message-Id: <87a7ld3yz4.fsf@morokweng.localdomain> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-12-10_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=722 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1812100183 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Michael, Michael Bringmann writes: > I have asked Scott Mayes to take a look at one of these crashes from > the phyp side. I will let you know if he finds anything notable. Thanks! It might make sense to test whether booting with cede_offline=off makes the bug go away. One suspicion I have is regarding the code handling CPU_STATE_INACTIVE. >From what I understand, it is a powerpc-specific CPU state and from the perspective of the generic CPU hotplug state machine, inactive CPUs are already fully offline. Which means that the locking performed by the generic code state machine doesn't apply to transitioning CPUs from INACTIVE to OFFLINE state. Perhaps the bug is that there is more than one CPU making that transition at the same time? That would cause two CPUs to call RTAS stop-self. I haven't checked whether this is really possible or not, though. It's just a conjecture. -- Thiago Jung Bauermann IBM Linux Technology Center