Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752081AbdGMMn0 (ORCPT ); Thu, 13 Jul 2017 08:43:26 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:50942 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751201AbdGMMnZ (ORCPT ); Thu, 13 Jul 2017 08:43:25 -0400 Date: Thu, 13 Jul 2017 05:43:18 -0700 From: "Paul E. McKenney" To: "Rafael J. Wysocki" Cc: Alex Shi , Tony Lindgren , Linux Kernel Mailing List , Linux PM , Linux OMAP Mailing List , Catalin Marinas , Will Deacon Subject: Re: Regression with suspicious RCU usage splats with cpu_pm change Reply-To: paulmck@linux.vnet.ibm.com References: <20170713070749.GE16509@atomide.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 17071312-0024-0000-0000-000002AF5CAB X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007360; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000214; SDB=6.00886962; UDB=6.00442796; IPR=6.00667103; BA=6.00005470; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00016213; XFM=3.00000015; UTC=2017-07-13 12:43:22 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17071312-0025-0000-0000-000044BDAFD9 Message-Id: <20170713124318.GK2393@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-07-13_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1706020000 definitions=main-1707130198 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 642 Lines: 18 On Thu, Jul 13, 2017 at 01:50:26PM +0200, Rafael J. Wysocki wrote: > On Thu, Jul 13, 2017 at 11:43 AM, Alex Shi wrote: > > > > On 07/13/2017 03:07 PM, Tony Lindgren wrote: > >> Hi, > >> > >> Looks like next-20170713 gives me a bunch of "suspicious RCU usage" > >> splats with cpuidle_coupled on duovero, see below. I bisected it down > >> to commit 2f027e003d05 ("cpu_pm: replace raw_notifier with > >> atomic_notifier"). > > OK, so I'm dropping this commit. You can surround idle-loop RCU-reading code with RCU_NONIDLE(). This will tell RCU to pay attention even though the CPU is otherwise idle. Thanx, Paul