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[209.132.180.67]) by mx.google.com with ESMTP id q8-v6si2293978pgh.675.2018.08.07.14.09.03; Tue, 07 Aug 2018 14:09:28 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2018-07-02 header.b=yOPfwluk; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726890AbeHGXYR (ORCPT + 99 others); Tue, 7 Aug 2018 19:24:17 -0400 Received: from aserp2130.oracle.com ([141.146.126.79]:55404 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726027AbeHGXYR (ORCPT ); Tue, 7 Aug 2018 19:24:17 -0400 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w77KwqYS019096; Tue, 7 Aug 2018 21:07:56 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=dJyam29PDDE6QitvWGmyy6aSietkx742fIB5ZI2T0FA=; b=yOPfwluk/19TwVY0p+g5plCW7CvBB3SV7w/oU3+/KEh8Qpx4yufGVAm2uXlNmKCC8loN cBXuJ9rTuNJYCCiJAI9VaGlRHsily2ftseEmYnFngtpk9Ig0gPVeKFRE4+/0D/ObnEee A9HiYYOqjZVPy6a6SBgAfluhXI6/Gx4zPvjWjlq9iflfnIjxGZ0++uyP6CDcfprNSSiI vZSiZFI+lmpwAZROfGkEU0QcJkQrZpRNDJQycZwlL5cpYsSWg7tc6zaGfrDUJ/ENOVU+ zBOiit3dL8tdKplwzzvR7N++LjbifC/wrMx80JHCMI6G5SnP/5uXdYMbw33jWKfdps5e HQ== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by aserp2130.oracle.com with ESMTP id 2kn1nd3cuw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 07 Aug 2018 21:07:55 +0000 Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w77L7rUe031852 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 7 Aug 2018 21:07:54 GMT Received: from abhmp0014.oracle.com (abhmp0014.oracle.com [141.146.116.20]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w77L7riK006215; Tue, 7 Aug 2018 21:07:53 GMT Received: from oracle.com (/10.154.176.65) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 07 Aug 2018 14:07:53 -0700 Date: Tue, 7 Aug 2018 17:07:54 -0400 From: Sowmini Varadhan To: syzbot Cc: davem@davemloft.net, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, rds-devel@oss.oracle.com, santosh.shilimkar@oracle.com, syzkaller-bugs@googlegroups.com Subject: Re: possible deadlock in rds_wake_sk_sleep Message-ID: <20180807210754.GE23593@oracle.com> References: <000000000000fb5cd90572de7ebd@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000000000000fb5cd90572de7ebd@google.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8978 signatures=668707 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=566 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1808070211 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (08/07/18 13:47), syzbot wrote: > Possible unsafe locking scenario: > > CPU0 CPU1 > ---- ---- > lock(&(&rm->m_rs_lock)->rlock); > lock(&rs->rs_recv_lock); > lock(&(&rm->m_rs_lock)->rlock); > lock(&rs->rs_recv_lock); > > *** DEADLOCK *** looks like a valid find, I think the deadlock should be avoided by having rds_clear_recv_queue do something like get rs_recv_lock un-tether the rs_recv_queue into a temporary list releease rs_recv_lock purge the rds_incoming temporary list I can give this a shot later this week. --Sowmini