From patchwork Wed Nov 20 18:54:11 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Jordan X-Patchwork-Id: 11254703 X-Patchwork-Delegate: herbert@gondor.apana.org.au Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 49B5214C0 for ; Wed, 20 Nov 2019 18:56:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A46120898 for ; Wed, 20 Nov 2019 18:56:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="DicE+rK1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727450AbfKTS4v (ORCPT ); Wed, 20 Nov 2019 13:56:51 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:36734 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727188AbfKTS4p (ORCPT ); Wed, 20 Nov 2019 13:56:45 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xAKIs6SO026177; Wed, 20 Nov 2019 18:56:38 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=corp-2019-08-05; bh=Vyk7zTFLGmHD7QT7ZBJLwCH8ALXYwWs90USs3NJmkNY=; b=DicE+rK1Z41itpwarsatmD35LAMDmvsVkGODi197rxL5f1t+iEAdOfHpastUmzmfBbva 0HHsFM5Ytro4KtRT63BYspxch8kievE3+eHfb93EyR7sf3Ifo7hju8FVEYv48QHmtlSm 1x+BBxga1uKXGs4In7u0KqKnC98QWF7wx4m9W9xfnce/hYL2O6GlpxRNrOt/z2w8+utO DsfiUjFa3jKk/1OvvUFlCLmZLTVP1z15VyeUjpc5CFIuMcDZi+Cv47dc2ILy0VQEDu4d beyBQYKQynvd7ZgOOUfbDCFxvA1LLwQSkvA6pvjRNfzVa01s2Ytts6qvq2VkcuqKqBXL KQ== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2130.oracle.com with ESMTP id 2wa8htyjep-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Nov 2019 18:56:37 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xAKIriiD139536; Wed, 20 Nov 2019 18:56:37 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3030.oracle.com with ESMTP id 2wd47vmgtm-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Nov 2019 18:56:36 +0000 Received: from abhmp0018.oracle.com (abhmp0018.oracle.com [141.146.116.24]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id xAKIuaLZ012933; Wed, 20 Nov 2019 18:56:36 GMT Received: from zissou.us.oracle.com (/10.152.34.58) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 20 Nov 2019 10:56:35 -0800 From: Daniel Jordan To: Herbert Xu , Steffen Klassert Cc: Eric Biggers , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, Daniel Jordan Subject: [PATCH 3/4] padata: always acquire cpu_hotplug_lock before pinst->lock Date: Wed, 20 Nov 2019 13:54:11 -0500 Message-Id: <20191120185412.302-4-daniel.m.jordan@oracle.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191120185412.302-1-daniel.m.jordan@oracle.com> References: <20191120185412.302-1-daniel.m.jordan@oracle.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9447 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1911200156 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9447 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default 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=8.0.1-1911140001 definitions=main-1911200156 Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org lockdep complains when padata's paths to update cpumasks via CPU hotplug and sysfs are both taken: # echo 0 > /sys/devices/system/cpu/cpu1/online # echo ff > /sys/kernel/pcrypt/pencrypt/parallel_cpumask ====================================================== WARNING: possible circular locking dependency detected 5.4.0-rc8-padata-cpuhp-v3+ #1 Not tainted ------------------------------------------------------ bash/205 is trying to acquire lock: ffffffff8286bcd0 (cpu_hotplug_lock.rw_sem){++++}, at: padata_set_cpumask+0x2b/0x120 but task is already holding lock: ffff8880001abfa0 (&pinst->lock){+.+.}, at: padata_set_cpumask+0x26/0x120 which lock already depends on the new lock. padata doesn't take cpu_hotplug_lock and pinst->lock in a consistent order. Which should be first? CPU hotplug calls into padata with cpu_hotplug_lock already held, so it should have priority. Fixes: 6751fb3c0e0c ("padata: Use get_online_cpus/put_online_cpus") Signed-off-by: Daniel Jordan Cc: Eric Biggers Cc: Herbert Xu Cc: Steffen Klassert Cc: linux-crypto@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- kernel/padata.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/padata.c b/kernel/padata.c index 5c9bd8df0f0f..cd9ae6822460 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -623,8 +623,8 @@ int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type, struct cpumask *serial_mask, *parallel_mask; int err = -EINVAL; - mutex_lock(&pinst->lock); get_online_cpus(); + mutex_lock(&pinst->lock); switch (cpumask_type) { case PADATA_CPU_PARALLEL: @@ -642,8 +642,8 @@ int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type, err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask); out: - put_online_cpus(); mutex_unlock(&pinst->lock); + put_online_cpus(); return err; }