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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 15 Apr 2019 11:56:42 +0100 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp22033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x3FAufM733554584 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 15 Apr 2019 10:56:41 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 67F31B2066; Mon, 15 Apr 2019 10:56:41 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 48118B205F; Mon, 15 Apr 2019 10:56:41 +0000 (GMT) Received: from paulmck-ThinkPad-W541 (unknown [9.85.174.176]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Mon, 15 Apr 2019 10:56:41 +0000 (GMT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id 623F816C0B95; Mon, 15 Apr 2019 03:56:45 -0700 (PDT) Date: Mon, 15 Apr 2019 03:56:45 -0700 From: "Paul E. McKenney" To: Sebastian Andrzej Siewior Cc: linux-kernel@vger.kernel.org Subject: Re: Alleged fix for writer stall on -rcu branch dev Reply-To: paulmck@linux.ibm.com References: <20190409221426.GA11212@linux.ibm.com> <20190410181538.3ocva5lmh7ghrisr@linutronix.de> <20190410184105.GR14111@linux.ibm.com> <20190410191918.g2yqnsmuqukmzdfe@linutronix.de> <20190410203302.GT14111@linux.ibm.com> <20190411000610.GA3867@linux.ibm.com> <20190413142153.GA17704@linux.ibm.com> <20190415104047.mrtmv6w6kq5m44fp@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190415104047.mrtmv6w6kq5m44fp@linutronix.de> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 19041510-0068-0000-0000-000003B53E78 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010931; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000284; SDB=6.01189390; UDB=6.00623175; IPR=6.00970177; MB=3.00026449; MTD=3.00000008; XFM=3.00000015; UTC=2019-04-15 10:56:43 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19041510-0069-0000-0000-0000482AA8BA Message-Id: <20190415105645.GQ14111@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-04-15_05:,, 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=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904150075 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 15, 2019 at 12:40:47PM +0200, Sebastian Andrzej Siewior wrote: > On 2019-04-13 07:21:53 [-0700], Paul E. McKenney wrote: > > > > And after ramping up the stress in rcutorture a bit, I am able to > > reproduce this CPU stall involving offlining on my systems. My plan is > > my usual one: Keep increasing rcutorture stress to get it to reproduce > > in reasonable time, add diagnostics as appropriate, and continue making > > forward-progress improvements in RCU itself. > > I *think* this one is also new: > > |Assertion failure in /home/bigeasy/linux-rt/tools/testing/selftests/rcutorture/res/2019.04.14-14:28:40/TREE03.37/console.log TREE03 > |Summary: Warnings: 6 Call Traces: 6 > https://breakpoint.cc/console-03.37.log This is new in rcutorture as well. It is complaining that we just got done with a stutter interval (in which torturing temporarily stops) but not everything has progressed through the callback chain to be freed. And in this case it is happening during rcutorture shutdown, so I need to check the callback -- I might need end-of-run checks in that WARN_ON(). > |Assertion failure in /home/bigeasy/linux-rt/tools/testing/selftests/rcutorture/res/2019.04.14-14:28:40/TREE03.39/console.log TREE03 > |Summary: Warnings: 4 Call Traces: 4 > https://breakpoint.cc/console-03.39.log And the same here. So neither count against you. ;-) Thanx, Paul > This is still commit 33e04e451279 ("torture: Allow inter-stutter interval to be > specified"). > > > Thank you very much for locating this one!!! > > You are welcome. > > > Thanx, Paul > > Sebastian >