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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH,UNPARSEABLE_RELAY,USER_AGENT_MUTT 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 6364DC04AB3 for ; Mon, 27 May 2019 10:08:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2C11620883 for ; Mon, 27 May 2019 10:08:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="WPgrpcS1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726114AbfE0KI0 (ORCPT ); Mon, 27 May 2019 06:08:26 -0400 Received: from aserp2130.oracle.com ([141.146.126.79]:36346 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725943AbfE0KI0 (ORCPT ); Mon, 27 May 2019 06:08:26 -0400 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x4R9xvfg176866; Mon, 27 May 2019 10:08:21 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : mime-version : content-type; s=corp-2018-07-02; bh=7AwDZ11tjsv4yyZSMPazjv2aTAUgse+ixjzcawJvK6Q=; b=WPgrpcS1Yd2jjNTLQBdsbhE8wFjY6EqPa1EuLiPNNJRpXyixSy1s+t+gmu/J7+e1mV08 UzOLdoaxO59WiKdyRkNAMQKiFR401KJ7I/cddDuKSdJz1/VZ5B8kruMm0i4dHLKqbfxk CnK+c69w2pzFkB4rcWT0UbfmY/GENoiaUCtEB4fmt04B1H13UFckMASgUTVI7dgOE2cv DCCTOk5K8iVH08c4zq85AhUvx7nODut53A33zir69lUsIWeR4U4aDPpuJk4U7sPp6PtH R6ERi1vlNIpSPLfk4RJbGWGN5H92xCrchIE4SYx8mZQYTpqO4eZdwOEFTfTGYu/MIWM9 Ng== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by aserp2130.oracle.com with ESMTP id 2spu7d5sem-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 27 May 2019 10:08:21 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x4RA86ER166342; Mon, 27 May 2019 10:08:20 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3020.oracle.com with ESMTP id 2sr31u5w44-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 27 May 2019 10:08:20 +0000 Received: from abhmp0011.oracle.com (abhmp0011.oracle.com [141.146.116.17]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x4RA8JhO021937; Mon, 27 May 2019 10:08:19 GMT Received: from mwanda (/41.57.98.10) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 27 May 2019 03:08:19 -0700 Date: Mon, 27 May 2019 13:08:08 +0300 From: Dan Carpenter To: axboe@kernel.dk Cc: linux-fsdevel@vger.kernel.org Subject: [bug report] io_uring: add support for sqe links Message-ID: <20190527100808.GA31410@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9269 signatures=668687 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905270072 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9269 signatures=668687 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=1 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=8.0.1-1810050000 definitions=main-1905270071 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hello Jens Axboe, The patch f3fafe4103bd: "io_uring: add support for sqe links" from May 10, 2019, leads to the following static checker warning: fs/io_uring.c:623 io_req_link_next() error: potential NULL dereference 'nxt'. fs/io_uring.c 614 static void io_req_link_next(struct io_kiocb *req) 615 { 616 struct io_kiocb *nxt; 617 618 nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb, list); 619 list_del(&nxt->list); ^^^^^^^^^ The warning is a false positive but this is a NULL dereference. 620 if (!list_empty(&req->link_list)) { 621 INIT_LIST_HEAD(&nxt->link_list); ^^^^^ False positive. 622 list_splice(&req->link_list, &nxt->link_list); 623 nxt->flags |= REQ_F_LINK; 624 } 625 626 INIT_WORK(&nxt->work, io_sq_wq_submit_work); ^^^^^^^^^^ 627 queue_work(req->ctx->sqo_wq, &nxt->work); ^^^^^^^^^^ Other bugs. 628 } regards, dan carpenter