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=-7.3 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,USER_AGENT_SANE_1 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 64719C433B4 for ; Wed, 21 Apr 2021 10:30:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D00B6140F for ; Wed, 21 Apr 2021 10:30:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233975AbhDUKbU (ORCPT ); Wed, 21 Apr 2021 06:31:20 -0400 Received: from aserp2130.oracle.com ([141.146.126.79]:34564 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233932AbhDUKbU (ORCPT ); Wed, 21 Apr 2021 06:31:20 -0400 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 13LAOBFw134312; Wed, 21 Apr 2021 10:30:44 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 : content-transfer-encoding : in-reply-to; s=corp-2020-01-29; bh=UVRmuI4K82J0Ob8tKR+GphxJcNJedcZ8D33jaobG+i8=; b=a/PDaIdrFL5DWiBAP4uQtEXYkYCW7OUow/4TGo68yp4DSFcMEIp4Rbu/wYw/Sta3n6Ez 4RZoo7oiHql3y7eRTp1yIa76mDtYaj8f9OH7pMWtdzQwBq7huJjiwT4BWpud7djDGjuu ELeyFOovGoyNMJA6bAUxBcyTm/kCeCdkrRpa+iYT5IIO3r0iLavdFzOJE13HuKW+90WW v81y2CnXZtmcdC6SbTaQytPpUo613eVEy053Dy6OSuyoRU/1m7WHhZqfBS6dDDVDNZpS v28O3I2DRockqTxM5yQ4NdztGPLorjbkHcPAVX7JhKGBFPS7Iu1lOxRrCxgPjpkDlOJ8 Ew== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by aserp2130.oracle.com with ESMTP id 37yn6c9wp3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 21 Apr 2021 10:30:44 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 13LAOom5138660; Wed, 21 Apr 2021 10:30:43 GMT Received: from pps.reinject (localhost [127.0.0.1]) by userp3030.oracle.com with ESMTP id 3809m0d252-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 21 Apr 2021 10:30:43 +0000 Received: from userp3030.oracle.com (userp3030.oracle.com [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 13LAUh9g156959; Wed, 21 Apr 2021 10:30:43 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3030.oracle.com with ESMTP id 3809m0d24g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 21 Apr 2021 10:30:43 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 13LAUgUI024548; Wed, 21 Apr 2021 10:30:42 GMT Received: from kadam (/102.36.221.92) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 21 Apr 2021 10:30:41 +0000 Date: Wed, 21 Apr 2021 13:30:36 +0300 From: Dan Carpenter To: =?iso-8859-1?Q?Aur=E9lien?= Aptel Cc: linux-sparse@vger.kernel.org Subject: Re: check idea: warn when mixing signedness in ?: operator (got bitten by this recently) Message-ID: <20210421103036.GG1981@kadam> References: <87wnsyzia4.fsf@suse.com> <20210420121602.GF1981@kadam> <87k0oxyvl3.fsf@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87k0oxyvl3.fsf@suse.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-GUID: gASZa8Ut7-4SDafwwETGWET-9sJyMhbf X-Proofpoint-ORIG-GUID: gASZa8Ut7-4SDafwwETGWET-9sJyMhbf X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=9960 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 priorityscore=1501 bulkscore=0 suspectscore=0 impostorscore=0 mlxscore=0 lowpriorityscore=0 clxscore=1015 spamscore=0 mlxlogscore=999 adultscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104210080 Precedence: bulk List-ID: X-Mailing-List: linux-sparse@vger.kernel.org On Tue, Apr 20, 2021 at 02:44:08PM +0200, Aurélien Aptel wrote: > Hi Dan, > > Dan Carpenter writes: > > Thanks for the idea. I can implement something like that in Smatch. > > I'll run the attached check over the kernel and see what it turns up. > > I've only used sparse I think (make C=1) I need to lookup how to use Smatch. > > > It says that it's only checking assignments but the trick is that > > Smatch creates fake assignments in the background for passing parameters > > or returning. So "return a ? uint_val : -ENOMEM;" will trigger an error > > message. > > Sounds good. > > > If there are too many false positives when I test this tonight, then I > > may make is_suspicious_int() more strict. > > If that's any help, the exact bug where we hit this is currently in > fs/cifs/file.c in collect_uncached_write_data(), this line: > > ctx->rc = (rc == 0) ? ctx->total_len : rc; > > Hopefully it shows up in your tests. > Yeah. It finds it. :) It works pretty well. The temptation is to ignore left shifts. Otherwise I think I will just push this. regards, dan carpenter fs/f2fs/segment.c:847 __remove_dirty_segment() warn: check sign expansion for '-1' fs/cifs/file.c:3177 collect_uncached_write_data() warn: check sign expansion for 'rc' drivers/staging/rtl8188eu/core/rtw_xmit.c:1006 rtw_xmitframe_coalesce() warn: check sign expansion for 'mpdu_len' drivers/usb/gadget/legacy/inode.c:501 ep_aio_complete() warn: check sign expansion for 'req->status' drivers/gpu/drm/nouveau/nouveau_hwmon.c:507 nouveau_in_read() warn: check sign expansion for '-19' drivers/gpu/drm/nouveau/nouveau_hwmon.c:510 nouveau_in_read() warn: check sign expansion for '-19' drivers/firmware/arm_scpi.c:556 scpi_clk_get_val() warn: check sign expansion for 'ret' drivers/clk/sunxi-ng/ccu_nm.c:158 ccu_nm_round_rate() warn: check sign expansion for '1 << nm->m.width' drivers/clk/sunxi-ng/ccu_nm.c:202 ccu_nm_set_rate() warn: check sign expansion for '1 << nm->m.width' drivers/clk/sunxi-ng/ccu_nkmp.c:149 ccu_nkmp_round_rate() warn: check sign expansion for '1 << nkmp->m.width' drivers/clk/sunxi-ng/ccu_nkmp.c:151 ccu_nkmp_round_rate() warn: check sign expansion for '1 << ((1 << nkmp->p.width) - 1)' drivers/clk/sunxi-ng/ccu_nkmp.c:180 ccu_nkmp_set_rate() warn: check sign expansion for '1 << nkmp->m.width' drivers/clk/sunxi-ng/ccu_nkmp.c:182 ccu_nkmp_set_rate() warn: check sign expansion for '1 << ((1 << nkmp->p.width) - 1)' drivers/clk/sunxi-ng/ccu_nkm.c:120 ccu_nkm_round_rate() warn: check sign expansion for '1 << nkm->m.width' drivers/clk/sunxi-ng/ccu_nkm.c:160 ccu_nkm_set_rate() warn: check sign expansion for '1 << nkm->m.width' drivers/net/ethernet/broadcom/bnxt/bnxt.c:9785 bnxt_show_temp() warn: check sign expansion for 'rc' drivers/soc/aspeed/aspeed-lpc-snoop.c:98 snoop_file_read() warn: check sign expansion for 'ret' samples/kfifo/bytestream-example.c:126 fifo_write() warn: check sign expansion for 'ret' samples/kfifo/bytestream-example.c:142 fifo_read() warn: check sign expansion for 'ret' samples/kfifo/record-example.c:133 fifo_write() warn: check sign expansion for 'ret' samples/kfifo/record-example.c:149 fifo_read() warn: check sign expansion for 'ret' samples/kfifo/inttype-example.c:119 fifo_write() warn: check sign expansion for 'ret' samples/kfifo/inttype-example.c:135 fifo_read() warn: check sign expansion for 'ret' net/sunrpc/svcsock.c:1177 svc_tcp_sendto() warn: check sign expansion for 'err'