From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031575AbeBNVmg (ORCPT ); Wed, 14 Feb 2018 16:42:36 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:38536 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031344AbeBNVmd (ORCPT ); Wed, 14 Feb 2018 16:42:33 -0500 Date: Wed, 14 Feb 2018 13:42:45 -0800 From: "Paul E. McKenney" To: Byungchul Park Cc: jiangshanlai@gmail.com, josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org, kernel-team@lge.com Subject: Re: [PATCH] srcu: Fix incorrect condition in srcu_funnel_exp_start() Reply-To: paulmck@linux.vnet.ibm.com References: <1518598794-26752-1-git-send-email-byungchul.park@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1518598794-26752-1-git-send-email-byungchul.park@lge.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 18021421-0040-0000-0000-000003F715B0 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00008535; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000253; SDB=6.00989773; UDB=6.00502609; IPR=6.00769127; MB=3.00019556; MTD=3.00000008; XFM=3.00000015; UTC=2018-02-14 21:42:30 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18021421-0041-0000-0000-000007F815DD Message-Id: <20180214214245.GS3617@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-02-14_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=1011 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1802140254 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 14, 2018 at 05:59:54PM +0900, Byungchul Park wrote: > We should've kept sp->srcu_gp_seq_needed_exp the furthest. But > it probably fails because of the incorrect condition. Fix it. > > Signed-off-by: Byungchul Park Good catch, and thank you for reviewing the SRCU code, but Ildar Ismagilov beat you to this one. Please see 574428dee1f3 ("rcu: Fix misprint in srcu_funnel_exp_start") in -rcu. Thanx, Paul > --- > kernel/rcu/srcutree.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c > index d5cea81..44bc0fa 100644 > --- a/kernel/rcu/srcutree.c > +++ b/kernel/rcu/srcutree.c > @@ -626,7 +626,7 @@ static void srcu_funnel_exp_start(struct srcu_struct *sp, struct srcu_node *snp, > spin_unlock_irqrestore_rcu_node(snp, flags); > } > spin_lock_irqsave_rcu_node(sp, flags); > - if (!ULONG_CMP_LT(sp->srcu_gp_seq_needed_exp, s)) > + if (ULONG_CMP_LT(sp->srcu_gp_seq_needed_exp, s)) > sp->srcu_gp_seq_needed_exp = s; > spin_unlock_irqrestore_rcu_node(sp, flags); > } > -- > 1.9.1 >