From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AAB9DC43142 for ; Tue, 26 Jun 2018 17:15:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 68C3F26E73 for ; Tue, 26 Jun 2018 17:15:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 68C3F26E73 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.vnet.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933402AbeFZRPa (ORCPT ); Tue, 26 Jun 2018 13:15:30 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:45120 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932068AbeFZRIv (ORCPT ); Tue, 26 Jun 2018 13:08:51 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w5QH5vpS053645 for ; Tue, 26 Jun 2018 13:08:51 -0400 Received: from e14.ny.us.ibm.com (e14.ny.us.ibm.com [129.33.205.204]) by mx0a-001b2d01.pphosted.com with ESMTP id 2juqk7p1c6-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 26 Jun 2018 13:08:51 -0400 Received: from localhost by e14.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 26 Jun 2018 13:08:50 -0400 Received: from b01cxnp22036.gho.pok.ibm.com (9.57.198.26) by e14.ny.us.ibm.com (146.89.104.201) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 26 Jun 2018 13:08:45 -0400 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp22036.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w5QH8ip0131434 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 26 Jun 2018 17:08:44 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6CD04B2064; Tue, 26 Jun 2018 13:08:38 -0400 (EDT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4FDA8B2071; Tue, 26 Jun 2018 13:08:38 -0400 (EDT) Received: from paulmck-ThinkPad-W541 (unknown [9.70.82.159]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Tue, 26 Jun 2018 13:08:38 -0400 (EDT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id CC92C16CA09F; Tue, 26 Jun 2018 10:10:49 -0700 (PDT) From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: 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, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 14/22] rcu: Add RCU-preempt check for waiting on newly onlined CPU Date: Tue, 26 Jun 2018 10:10:40 -0700 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180626002052.GA24146@linux.vnet.ibm.com> References: <20180626002052.GA24146@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18062617-0052-0000-0000-000003045DA2 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009259; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000266; SDB=6.01052668; UDB=6.00539669; IPR=6.00830593; MB=3.00021864; MTD=3.00000008; XFM=3.00000015; UTC=2018-06-26 17:08:49 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18062617-0053-0000-0000-00005D25E429 Message-Id: <20180626171048.2181-14-paulmck@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-06-26_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=737 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1806210000 definitions=main-1806260192 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org RCU should only be waiting on CPUs that were online at the time that the current grace period started. Failure to abide by this rule can result in confusing splats during grace-period cleanup and initialization. This commit therefore adds a check to RCU-preempt's preempted-task queuing that checks for waiting on newly onlined CPUs. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree_plugin.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 1c9a836af5b6..6b85ce936ad4 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -183,6 +183,9 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp) raw_lockdep_assert_held_rcu_node(rnp); WARN_ON_ONCE(rdp->mynode != rnp); WARN_ON_ONCE(!rcu_is_leaf_node(rnp)); + /* RCU better not be waiting on newly onlined CPUs! */ + WARN_ON_ONCE(rnp->qsmaskinitnext & ~rnp->qsmaskinit & rnp->qsmask & + rdp->grpmask); /* * Decide where to queue the newly blocked task. In theory, -- 2.17.1