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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 30 Aug 2018 19:12:10 -0400 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp23033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w7UNC92n26017952 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 30 Aug 2018 23:12:09 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 00DF7B2065; Thu, 30 Aug 2018 19:11:04 -0400 (EDT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D4CC4B2064; Thu, 30 Aug 2018 19:11:03 -0400 (EDT) Received: from paulmck-ThinkPad-W541 (unknown [9.70.82.159]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Thu, 30 Aug 2018 19:11:03 -0400 (EDT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id 4EFDC16C061E; Thu, 30 Aug 2018 16:12:11 -0700 (PDT) Date: Thu, 30 Aug 2018 16:12:11 -0700 From: "Paul E. McKenney" To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, Tejun Heo Subject: Re: [PATCH tip/core/rcu 3/3] srcu: Make early-boot call_srcu() reuse workqueue lists Reply-To: paulmck@linux.vnet.ibm.com References: <20180829212036.GA22033@linux.vnet.ibm.com> <20180829212313.22903-3-paulmck@linux.vnet.ibm.com> <20180829215616.1c10e476@vmware.local.home> <20180830020701.GE4225@linux.vnet.ibm.com> <20180829224609.5ffdc9ec@vmware.local.home> <20180830032315.GG4225@linux.vnet.ibm.com> <20180830124444.6bb9faac@gandalf.local.home> <20180830173509.GL4225@linux.vnet.ibm.com> <20180830173742.GA17677@linux.vnet.ibm.com> <20180830143617.2fb85e23@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180830143617.2fb85e23@gandalf.local.home> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 18083023-0052-0000-0000-00000328DD8E X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009641; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000266; SDB=6.01081234; UDB=6.00557792; IPR=6.00861218; MB=3.00023023; MTD=3.00000008; XFM=3.00000015; UTC=2018-08-30 23:12:14 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18083023-0053-0000-0000-00005DE90D98 Message-Id: <20180830231211.GW4225@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-08-30_08:,, 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=8.0.1-1807170000 definitions=main-1808300231 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 30, 2018 at 02:36:17PM -0400, Steven Rostedt wrote: > On Thu, 30 Aug 2018 10:37:42 -0700 > "Paul E. McKenney" wrote: > > > > > > But still triggered the following: > > > > > > > > WARNING: CPU: 0 PID: 0 at /work/git/linux-trace.git/kernel/rcu/srcutree.c:242 check_init_srcu_struct+0x85/0x90 > > > > > > Gah!!! I needed to have removed that WARN_ON_ONCE(), didn't I? > > > In fact, I should have removed that once I started using workqueues, > > > quite some time back. > > > > As in the below patch. > > > > Thanx, Paul > > > > ------------------------------------------------------------------------ > > > > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c > > index 75571ff09c62..a8846ed7f352 100644 > > --- a/kernel/rcu/srcutree.c > > +++ b/kernel/rcu/srcutree.c > > @@ -239,7 +239,6 @@ static void check_init_srcu_struct(struct srcu_struct *sp) > > { > > unsigned long flags; > > > > - WARN_ON_ONCE(rcu_scheduler_active == RCU_SCHEDULER_INIT); > > Well it boots without warning ;-) > > Tested-by: Steven Rostedt (VMware) Thank you again! I applied this to 1/3 and 3/3 on the assumption that you did not run rcutorture. ;-) Thanx, Paul > -- Steve > > > /* The smp_load_acquire() pairs with the smp_store_release(). */ > > if (!rcu_seq_state(smp_load_acquire(&sp->srcu_gp_seq_needed))) /*^^^*/ > > return; /* Already initialized. */ >