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=-3.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY autolearn=no 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 45CF9C388F7 for ; Fri, 13 Nov 2020 09:01:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DB48E2078D for ; Fri, 13 Nov 2020 09:01:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="aJuu8wEV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726221AbgKMJBF (ORCPT ); Fri, 13 Nov 2020 04:01:05 -0500 Received: from aserp2130.oracle.com ([141.146.126.79]:49538 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726181AbgKMJBB (ORCPT ); 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Fri, 13 Nov 2020 09:00:56 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3020.oracle.com with ESMTP id 34rt57gy16-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 13 Nov 2020 09:00:56 +0000 Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 0AD90t5s014324; Fri, 13 Nov 2020 09:00:55 GMT Received: from mwanda (/10.175.206.108) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 13 Nov 2020 01:00:55 -0800 Date: Fri, 13 Nov 2020 12:00:49 +0300 From: Dan Carpenter To: mszeredi@redhat.com Cc: linux-fsdevel@vger.kernel.org Subject: [bug report] fuse: get rid of fuse_mount refcount Message-ID: <20201113090049.GA95467@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9803 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 bulkscore=0 mlxscore=0 mlxlogscore=982 suspectscore=10 adultscore=0 phishscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011130054 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9803 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 lowpriorityscore=0 priorityscore=1501 clxscore=1011 malwarescore=0 mlxscore=0 spamscore=0 suspectscore=10 mlxlogscore=972 impostorscore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011130054 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hello Miklos Szeredi, The patch 514b5e3ff45e: "fuse: get rid of fuse_mount refcount" from Nov 11, 2020, leads to the following static checker warning: fs/fuse/virtio_fs.c:1451 virtio_fs_get_tree() error: double free of 'fm' fs/fuse/virtio_fs.c 1418 if (!fs) { 1419 pr_info("virtio-fs: tag <%s> not found\n", fsc->source); 1420 return -EINVAL; 1421 } 1422 1423 err = -ENOMEM; 1424 fc = kzalloc(sizeof(struct fuse_conn), GFP_KERNEL); 1425 if (!fc) 1426 goto out_err; 1427 1428 fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL); 1429 if (!fm) 1430 goto out_err; 1431 1432 fuse_conn_init(fc, fm, get_user_ns(current_user_ns()), 1433 &virtio_fs_fiq_ops, fs); 1434 fc->release = fuse_free_conn; 1435 fc->delete_stale = true; 1436 fc->auto_submounts = true; 1437 1438 fsc->s_fs_info = fm; 1439 sb = sget_fc(fsc, virtio_fs_test_super, set_anon_super_fc); 1440 if (fsc->s_fs_info) { 1441 fuse_conn_put(fc); 1442 kfree(fm); ^^^^^^^^^ Freed here 1443 } 1444 if (IS_ERR(sb)) 1445 return PTR_ERR(sb); 1446 1447 if (!sb->s_root) { 1448 err = virtio_fs_fill_super(sb, fsc); 1449 if (err) { 1450 fuse_conn_put(fc); 1451 kfree(fm); ^^^^^^^^^ Double free 1452 sb->s_fs_info = NULL; I'm sort of surprised this is setting "sb->" instead of "fsc->". 1453 deactivate_locked_super(sb); 1454 return err; 1455 } 1456 1457 sb->s_flags |= SB_ACTIVE; 1458 } regards, dan carpenter