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=-13.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 E1376C11F6A for ; Wed, 30 Jun 2021 05:42:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F65461D23 for ; Wed, 30 Jun 2021 05:42:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229532AbhF3FpR (ORCPT ); Wed, 30 Jun 2021 01:45:17 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:41822 "EHLO mx0b-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229510AbhF3FpQ (ORCPT ); Wed, 30 Jun 2021 01:45:16 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 15U5YiA8062858; Wed, 30 Jun 2021 01:42:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=date : from : to : cc : subject : message-id : reply-to : references : mime-version : content-type : content-transfer-encoding : in-reply-to; s=pp1; bh=oZQ9636NLf23VbLHwcXpCEz97s8LtbkAJkNghES0cAw=; b=OZgcwi5j8P9zwlQVAEReTOARnDFBNknJTPSJ47hozgUN0ZQRzpsa4aD6wcht36fQ9dFo /2ap1KZ+SC8nk9dJalRipuV3JOrSW/lZEU0W6w/Ofi+g/4b3Pv78et6ieEgxmYU5qSuF MUk/D0zjPVnYE8SGLCZjCYnf8pLXHcHoU1vMEctu8UwYJZJ1yXrXLscCjv9QRYpG82uJ K05YQ6RPMLPW+XgypLXlft+df2CNWpQjtyKa3gpirz5n4hp4XkuzKIp4RGsTDe7cF1Dn c9LOvXmyRTXDmyA683HCdF7xfARP1oXCSiZCkd8oYgRAqv1NfSJoWlX8nwuMW/0gL5rB GQ== Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 39gewpmsbs-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 30 Jun 2021 01:42:29 -0400 Received: from pps.filterd (ppma03ams.nl.ibm.com [127.0.0.1]) by ppma03ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 15U5bbC0029670; Wed, 30 Jun 2021 05:42:28 GMT Received: from b06cxnps4074.portsmouth.uk.ibm.com (d06relay11.portsmouth.uk.ibm.com [9.149.109.196]) by ppma03ams.nl.ibm.com with ESMTP id 39duv89kby-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 30 Jun 2021 05:42:28 +0000 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 15U5gPU435914088 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 30 Jun 2021 05:42:25 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C14E0A4066; Wed, 30 Jun 2021 05:42:25 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1F150A405B; Wed, 30 Jun 2021 05:42:24 +0000 (GMT) Received: from linux.vnet.ibm.com (unknown [9.126.150.29]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 30 Jun 2021 05:42:23 +0000 (GMT) Date: Wed, 30 Jun 2021 11:12:22 +0530 From: Srikar Dronamraju To: C?dric Le Goater Cc: linuxppc-dev@lists.ozlabs.org, Michael Ellerman , stable@vger.kernel.org, Geetika Moolchandani Subject: Re: [PATCH] powerpc/xive: Do not skip CPU-less nodes when creating the IPIs Message-ID: <20210630054222.GX2633526@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20210629131542.743888-1-clg@kaod.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210629131542.743888-1-clg@kaod.org> X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 5d_LAVMwoBCrE1FgdjJudfK9lHyNMMFh X-Proofpoint-GUID: 5d_LAVMwoBCrE1FgdjJudfK9lHyNMMFh X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-06-30_01:2021-06-29,2021-06-30 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 priorityscore=1501 mlxscore=0 malwarescore=0 adultscore=0 bulkscore=0 suspectscore=0 impostorscore=0 clxscore=1011 mlxlogscore=999 phishscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2106300034 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org * C?dric Le Goater [2021-06-29 15:15:42]: > On PowerVM, CPU-less nodes can be populated with hot-plugged CPUs at > runtime. Today, the IPI is not created for such nodes, and hot-plugged > CPUs use a bogus IPI, which leads to soft lockups. > > We could create the node IPI on demand but it is a bit complex because > this code would be called under bringup_up() and some IRQ locking is > being done. The simplest solution is to create the IPIs for all nodes > at startup. Thanks for quickly coming up with the fix. > > Fixes: 7dcc37b3eff9 ("powerpc/xive: Map one IPI interrupt per node") > Cc: stable@vger.kernel.org # v5.13 > Reported-by: Geetika Moolchandani > Cc: Srikar Dronamraju > Signed-off-by: Cédric Le Goater Tested-by: Srikar Dronamraju > --- > > This patch breaks old versions of irqbalance (<= v1.4). Possible nodes > are collected from /sys/devices/system/node/ but CPU-less nodes are > not listed there. When interrupts are scanned, the link representing > the node structure is NULL and segfault occurs. > > Version 1.7 seems immune. > > --- > arch/powerpc/sysdev/xive/common.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c > index f3b16ed48b05..5d2c58dba57e 100644 > --- a/arch/powerpc/sysdev/xive/common.c > +++ b/arch/powerpc/sysdev/xive/common.c > @@ -1143,10 +1143,6 @@ static int __init xive_request_ipi(void) > struct xive_ipi_desc *xid = &xive_ipis[node]; > struct xive_ipi_alloc_info info = { node }; > > - /* Skip nodes without CPUs */ > - if (cpumask_empty(cpumask_of_node(node))) > - continue; > - > /* > * Map one IPI interrupt per node for all cpus of that node. > * Since the HW interrupt number doesn't have any meaning, > -- > 2.31.1 > -- Thanks and Regards Srikar Dronamraju