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=-1.0 required=3.0 tests=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 39A42C2BA19 for ; Mon, 6 Apr 2020 10:55:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 075552072A for ; Mon, 6 Apr 2020 10:55:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="y1ozHf2w" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727181AbgDFKz5 (ORCPT ); Mon, 6 Apr 2020 06:55:57 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:53828 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726841AbgDFKz5 (ORCPT ); Mon, 6 Apr 2020 06:55:57 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 036ArY7p143326; Mon, 6 Apr 2020 10:55:54 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-2020-01-29; bh=JwYn2yunv96QXSp1F9XTuPw1UGimn+c4Xb86LD10VIs=; b=y1ozHf2wGxnSE35g3upIAIpXTaMISZm3I3ibsp5y3uTxH9KEbeGjREd08cH/8nVufFzQ CfwyBYT+HwrEjdQat5MKjzzGkacDjirG53qnIHy8D55EAXjmyw1MR5uhxs8EXV0Wox9n 551Y66djrKT781k6HIUX3f6RXpWuu8V7QoF1BWbXugzOeVqpAcMoT4gnGN2sUfSGscIN UVj/i8AeLkUkhS5P+SnX54DsNYzB3FMoBPWikXPv5ngtIrPpWpGUUtlY2lLvp/P9cS2f YB1CNnszMigV34pb/71Ym1k13XecSwcOsWLsaxDzdRkPQ9ElWvX8PNuCjyMi+IDTUXyO NQ== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2120.oracle.com with ESMTP id 306jvmx19x-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 06 Apr 2020 10:55:54 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 036AqZnQ114890; Mon, 6 Apr 2020 10:55:53 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3030.oracle.com with ESMTP id 3073sppy4n-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 06 Apr 2020 10:55:53 +0000 Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 036Atq1U015004; Mon, 6 Apr 2020 10:55:52 GMT Received: from mwanda (/41.57.98.10) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 06 Apr 2020 03:55:51 -0700 Date: Mon, 6 Apr 2020 13:55:45 +0300 From: Dan Carpenter To: andreyknvl@google.com Cc: Andrey Konovalov , linux-usb@vger.kernel.org Subject: [bug report] usb: gadget: add raw-gadget interface Message-ID: <20200406105545.GA35744@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9582 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 phishscore=0 spamscore=0 malwarescore=0 suspectscore=3 adultscore=0 bulkscore=0 mlxlogscore=551 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004060095 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9582 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 suspectscore=3 mlxlogscore=599 mlxscore=0 bulkscore=0 adultscore=0 priorityscore=1501 lowpriorityscore=0 clxscore=1015 malwarescore=0 impostorscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004060095 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Hello Andrey Konovalov, The patch f2c2e717642c: "usb: gadget: add raw-gadget interface" from Feb 24, 2020, leads to the following static checker warning: drivers/usb/gadget/legacy/raw_gadget.c:102 raw_event_queue_fetch() warn: inconsistent returns 'queue->sema'. Locked on : 96,102 Unlocked on: 93 drivers/usb/gadget/legacy/raw_gadget.c 81 static struct usb_raw_event *raw_event_queue_fetch( 82 struct raw_event_queue *queue) 83 { 84 unsigned long flags; 85 struct usb_raw_event *event; 86 87 /* 88 * This function can be called concurrently. We first check that 89 * there's at least one event queued by decrementing the semaphore, 90 * and then take the lock to protect queue struct fields. 91 */ 92 if (down_interruptible(&queue->sema)) 93 return NULL; 94 spin_lock_irqsave(&queue->lock, flags); 95 if (WARN_ON(!queue->size)) 96 return NULL; I'm going to have investigate to see why Smatch doesn't complain that we have disabled IRQs on this path... Anyway, this doesn't seem like it can be correct. I get that this is a WARN_ON() path, but we're leaving the computer in a very screwed up state we don't at least enable IRQs. 97 event = queue->events[0]; 98 queue->size--; 99 memmove(&queue->events[0], &queue->events[1], 100 queue->size * sizeof(queue->events[0])); 101 spin_unlock_irqrestore(&queue->lock, flags); 102 return event; 103 } regards, dan carpenter