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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Sun, 12 May 2019 01:39:16 +0100 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp22035.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x4C0dFKT27656440 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 12 May 2019 00:39:15 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3DA6EB2068; Sun, 12 May 2019 00:39:15 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2669BB2064; Sun, 12 May 2019 00:39:15 +0000 (GMT) Received: from paulmck-ThinkPad-W541 (unknown [9.85.145.78]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Sun, 12 May 2019 00:39:15 +0000 (GMT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id CDB2816C6B82; Sat, 11 May 2019 17:39:15 -0700 (PDT) Date: Sat, 11 May 2019 17:39:15 -0700 From: "Paul E. McKenney" To: Andrea Parri Cc: Peter Zijlstra , Steven Rostedt , linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Juri Lelli , Morten Rasmussen , joelaf@google.com, Vincent Guittot , Sebastian Andrzej Siewior Subject: Re: Question about sched_setaffinity() Reply-To: paulmck@linux.ibm.com References: <20190430115551.GT2623@hirez.programming.kicks-ass.net> <20190501191213.GX3923@linux.ibm.com> <20190501151655.51469a4c@gandalf.local.home> <20190501202713.GY3923@linux.ibm.com> <20190507221613.GA11057@linux.ibm.com> <20190509173654.GA23530@linux.ibm.com> <20190509193625.GA12455@linux.ibm.com> <20190510120819.GR2589@hirez.programming.kicks-ass.net> <20190510230742.GY3923@linux.ibm.com> <20190511214520.GA3251@andrea> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190511214520.GA3251@andrea> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 19051200-0040-0000-0000-000004EE6F65 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00011087; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000285; SDB=6.01202010; UDB=6.00630814; IPR=6.00982909; MB=3.00026851; MTD=3.00000008; XFM=3.00000015; UTC=2019-05-12 00:39:18 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19051200-0041-0000-0000-000008FA7B73 Message-Id: <20190512003915.GD3923@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-05-11_16:,, 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-1905120002 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 11, 2019 at 11:45:20PM +0200, Andrea Parri wrote: > > > The below trace explain the issue. Some Paul person did it, see below. > > > It's broken per construction :-) > > > > *facepalm* Hence the very strange ->cpus_allowed mask. I really > > should have figured that one out. > > > > The fix is straightforward. I just added "rcutorture.shuffle_interval=0" > > to the TRIVIAL.boot file, which stops rcutorture from shuffling its > > kthreads around. > > I added the option to the file and I didn't reproduce the issue. Thank you! May I add your Tested-by? Thanx, Paul > > Please accept my apologies for the hassle, and thank you for tracking > > this down!!! > > Peter (echoing Paul): Thank you for pointing that shuffler out! > > Andrea >