From patchwork Tue Oct 29 11:41:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ursula Braun X-Patchwork-Id: 1186048 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 472V6Z1ltjz9sPT for ; Tue, 29 Oct 2019 22:41:42 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731914AbfJ2Llk (ORCPT ); Tue, 29 Oct 2019 07:41:40 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:50148 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725776AbfJ2Llk (ORCPT ); Tue, 29 Oct 2019 07:41:40 -0400 Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x9TBb6IO143834 for ; Tue, 29 Oct 2019 07:41:38 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0b-001b2d01.pphosted.com with ESMTP id 2vxmeq0t6p-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 29 Oct 2019 07:41:38 -0400 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 29 Oct 2019 11:41:34 -0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x9TBevBr18284994 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 29 Oct 2019 11:40:57 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1FA7352051; Tue, 29 Oct 2019 11:41:31 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id B687D52059; Tue, 29 Oct 2019 11:41:30 +0000 (GMT) From: Ursula Braun To: davem@davemloft.net Cc: netdev@vger.kernel.org, linux-s390@vger.kernel.org, gor@linux.ibm.com, heiko.carstens@de.ibm.com, raspl@linux.ibm.com, kgraul@linux.ibm.com, ubraun@linux.ibm.com Subject: [PATCH net 1/1] net/smc: fix refcounting for non-blocking connect() Date: Tue, 29 Oct 2019 12:41:26 +0100 X-Mailer: git-send-email 2.17.1 X-TM-AS-GCONF: 00 x-cbid: 19102911-0016-0000-0000-000002BEC0A7 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19102911-0017-0000-0000-000033201812 Message-Id: <20191029114126.59907-1-ubraun@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-10-29_03:, , 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=977 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1910290118 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org If a nonblocking socket is immediately closed after connect(), the connect worker may not have started. This results in a refcount problem, since sock_hold() is called from the connect worker. This patch moves the sock_hold in front of the connect worker scheduling. Reported-by: syzbot+4c063e6dea39e4b79f29@syzkaller.appspotmail.com Fixes: 50717a37db03 ("net/smc: nonblocking connect rework") Reviewed-by: Karsten Graul Signed-off-by: Ursula Braun --- net/smc/af_smc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index cea3c36ea0da..47946f489fd4 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -707,8 +707,6 @@ static int __smc_connect(struct smc_sock *smc) int smc_type; int rc = 0; - sock_hold(&smc->sk); /* sock put in passive closing */ - if (smc->use_fallback) return smc_connect_fallback(smc, smc->fallback_rsn); @@ -853,6 +851,8 @@ static int smc_connect(struct socket *sock, struct sockaddr *addr, rc = kernel_connect(smc->clcsock, addr, alen, flags); if (rc && rc != -EINPROGRESS) goto out; + + sock_hold(&smc->sk); /* sock put in passive closing */ if (flags & O_NONBLOCK) { if (schedule_work(&smc->connect_work)) smc->connect_nonblock = 1;