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=-5.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED 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 86AB2C4361B for ; Wed, 9 Dec 2020 02:43:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1762A23B23 for ; Wed, 9 Dec 2020 02:43:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726754AbgLICnF (ORCPT ); Tue, 8 Dec 2020 21:43:05 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:49132 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725877AbgLICnE (ORCPT ); Tue, 8 Dec 2020 21:43:04 -0500 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0B92ZW6D015259; Wed, 9 Dec 2020 02:41:13 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : in-reply-to : references : date : message-id : mime-version : content-type; s=corp-2020-01-29; bh=vhPAwGbX5UKJfIemCq3LE77ldW/MS6Z/BCzHi9otysg=; b=T4qPBYnl6CDw7MhxbLNUcQjfUzICtHe7Qj9GkVpSQmPaYMc0vvfQl536HZLiYJTvoNJ9 jVA851tnFUxV62TxuNng9POPjnJibMO3kJeLdLP1o1Fk6m2M/EpmZYaxGU+9aRc27Co5 bVG0eIucX9pBiqAYyJBL3xcODZJgNK3QhdPLWXGwucydXvAMr25NL+Zvl/dCOW0NmPkn nQ3IS9QIgBUoraAEHf7P56v8UAdAsGwRTD+nHgSQetz1MF7CyaV55tU9Wu1hv+2lRvOA EdWQ9Gpd5doM08dD2BbYWdVB8UJuefPMG/FwZoN+G+ZNF3Vbbqd00W667q8W20J4gMsj Nw== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by aserp2120.oracle.com with ESMTP id 35825m5yd2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 09 Dec 2020 02:41:13 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0B92ZnNX160888; Wed, 9 Dec 2020 02:41:12 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3030.oracle.com with ESMTP id 358m4ytt8w-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 09 Dec 2020 02:41:12 +0000 Received: from abhmp0018.oracle.com (abhmp0018.oracle.com [141.146.116.24]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 0B92f6B2032250; Wed, 9 Dec 2020 02:41:06 GMT Received: from parnassus (/98.229.125.203) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 08 Dec 2020 18:41:05 -0800 From: Daniel Jordan To: Peter Zijlstra , Alexey Klimov Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, yury.norov@gmail.com, tglx@linutronix.de, jobaker@redhat.com, audralmitchel@gmail.com, arnd@arndb.de, gregkh@linuxfoundation.org, rafael@kernel.org, tj@kernel.org, lizefan@huawei.com, qais.yousef@arm.com, hannes@cmpxchg.org, klimov.linux@gmail.com Subject: Re: [RFC][PATCH] cpu/hotplug: wait for cpuset_hotplug_work to finish on cpu online In-Reply-To: <20201207083827.GD3040@hirez.programming.kicks-ass.net> References: <20201203171431.256675-1-aklimov@redhat.com> <20201207083827.GD3040@hirez.programming.kicks-ass.net> Date: Tue, 08 Dec 2020 21:40:57 -0500 Message-ID: <87k0tritvq.fsf@oracle.com> MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9829 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 spamscore=0 suspectscore=0 bulkscore=0 malwarescore=0 phishscore=0 adultscore=0 mlxlogscore=979 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012090015 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9829 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 adultscore=0 bulkscore=0 phishscore=0 mlxlogscore=978 clxscore=1015 priorityscore=1501 mlxscore=0 spamscore=0 lowpriorityscore=0 malwarescore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012090015 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Peter Zijlstra writes: >> The nature of this bug is also described here (with different consequences): >> https://lore.kernel.org/lkml/20200211141554.24181-1-qais.yousef@arm.com/ > > Yeah, pesky deadlocks.. someone was going to try again. I dug up the synchronous patch https://lore.kernel.org/lkml/1579878449-10164-1-git-send-email-prsood@codeaurora.org/ but surprisingly wasn't able to reproduce the lockdep splat from https://lore.kernel.org/lkml/F0388D99-84D7-453B-9B6B-EEFF0E7BE4CC@lca.pw/ even though I could hit it a few weeks ago. I'm going to try to mess with it later, but don't let me hold this up.