From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3x3sHN5lLrzDr5N for ; Fri, 7 Jul 2017 21:06:24 +1000 (AEST) Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v67B5lpU045757 for ; Fri, 7 Jul 2017 07:06:22 -0400 Received: from e23smtp07.au.ibm.com (e23smtp07.au.ibm.com [202.81.31.140]) by mx0a-001b2d01.pphosted.com with ESMTP id 2bj0wq09ua-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 07 Jul 2017 07:06:21 -0400 Received: from localhost by e23smtp07.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 7 Jul 2017 21:06:18 +1000 Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay08.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v67B6FPd10551718 for ; Fri, 7 Jul 2017 21:06:15 +1000 Received: from d23av03.au.ibm.com (localhost [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v67B66P3031666 for ; Fri, 7 Jul 2017 21:06:07 +1000 Subject: Re: [linux-next] cpus stalls detected few hours after booting next kernel From: Abdul Haleem To: Nicholas Piggin Cc: sachinp , Stephen Rothwell , Paul McKenney , linux-kernel , linux-next , paulus@samba.org, paulmck@linux.vnet.ibm.com, linuxppc-dev Date: Fri, 07 Jul 2017 16:36:10 +0530 In-Reply-To: <20170630172802.6d4ddca2@roar.ozlabs.ibm.com> References: <1498728106.19484.21.camel@abdul> <20170629193614.376e27e6@roar.ozlabs.ibm.com> <20170629202305.6187367f@roar.ozlabs.ibm.com> <20170630004534.228f7c08@roar.ozlabs.ibm.com> <1498800138.19484.25.camel@abdul> <20170630172802.6d4ddca2@roar.ozlabs.ibm.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Message-Id: <1499425570.19784.38.camel@abdul.in.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 2017-06-30 at 17:28 +1000, Nicholas Piggin wrote: > On Fri, 30 Jun 2017 10:52:18 +0530 > Abdul Haleem wrote: > > > On Fri, 2017-06-30 at 00:45 +1000, Nicholas Piggin wrote: > > > On Thu, 29 Jun 2017 20:23:05 +1000 > > > Nicholas Piggin wrote: > > > > > > > On Thu, 29 Jun 2017 19:36:14 +1000 > > > > Nicholas Piggin wrote: > > > > > > > > I don't *think* the replay-wakeup-interrupt patch is directly involved, but > > > > > it's likely to be one of the idle patches. > > > > > > Okay this turned out to be misconfigured sleep states I added for the > > > simulator, sorry for the false alarm. > > > > > > > Although you have this in the backtrace. I wonder if that's a stuck > > > > lock in rcu_process_callbacks? > > > > > > So this spinlock becomes top of the list of suspects. Can you try > > > enabling lockdep and try to reproduce it? > > > > Yes, recreated again with CONFIG_LOCKDEP=y & CONFIG_DEBUG_LOCKDEP=y set. > > I do not see any difference in trace messages with and without LOCKDEP > > enabled. > > > > Please find the attached log file. > > Can you get an rcu_invoke_callback event trace that Paul suggested? Yes, I was able to collect the perf data for rcu_invoke_callback event on recent next kernel (4.12.0-next-20170705). the issue is rare to hit. After booting the next kernel, I started this command 'perf record -e rcu:rcu_invoke_callback -a -g -- cat' and waited for 30 minutes. five minutes after seeing the stalls messages, I did CTRL-C to end the perf command. @Nicholas : the perf.data report is too huge to attach here, shall I ping you the internal location of file on slack/mail ? Also the machine is in the same state if you want to use it ? > > Does this bug show up with just the powerpc next branch? > > Thanks, > Nick > -- Regard's Abdul Haleem IBM Linux Technology Centre