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=0.1 required=3.0 tests=BIGNUM_EMAILS,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_MUTT 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 4055EC4360F for ; Wed, 3 Apr 2019 06:15:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DE54620882 for ; Wed, 3 Apr 2019 06:15:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="lkcQCvw8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725908AbfDCGPY (ORCPT ); Wed, 3 Apr 2019 02:15:24 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:43478 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725879AbfDCGPY (ORCPT ); Wed, 3 Apr 2019 02:15:24 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x3363dfh020161; Wed, 3 Apr 2019 06:15:21 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=FXWGszBwk+zJdu+WCpXoCjQuCfGIl2iMj82QTScq6wU=; b=lkcQCvw8m1/taxzOyf5eJpYnX6odJswgMNuGMeXdu0HZyJbMF/ywRTtQRcRSZM91Tcin 8U228GwJOPNUlwin9QP9EW+my3+6HwWYBubIMTJzTs5WAHCHy5ql/ytKr0NtaFHtM4O3 6eeoU7GcdB/UBso0wQP3B904XW87Cd2Dl5Urh26M0D6lWlSWVhyq0u3np1Hkv9S5JjZ3 uHK78oMlet+nVidPi0Ju+yuXpk+AQcxi76C6Q2jJRUL7MI0WQLRBWHh57Y3HFRfPVSvc pvzeYoHLFsn0rUIKk81FHPqzpO2gsL4rBo3JeRfgyUPyXGNoFLZeu31l5P8QyR1t0+HD rg== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by aserp2120.oracle.com with ESMTP id 2rj0dnp2nr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 03 Apr 2019 06:15:21 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x336Dt8Z152433; Wed, 3 Apr 2019 06:15:20 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3030.oracle.com with ESMTP id 2rm8f4wra7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 03 Apr 2019 06:15:20 +0000 Received: from abhmp0018.oracle.com (abhmp0018.oracle.com [141.146.116.24]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x336FJTv029986; Wed, 3 Apr 2019 06:15:20 GMT Received: from kadam (/41.202.241.37) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 02 Apr 2019 23:15:19 -0700 Date: Wed, 3 Apr 2019 09:15:12 +0300 From: Dan Carpenter To: paolo.valente@linaro.org Cc: linux-block@vger.kernel.org Subject: [bug report] block, bfq: update blkio stats outside the scheduler lock Message-ID: <20190403061512.GA1618@kadam> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9215 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=703 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904030041 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9215 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=754 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904030041 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hello Paolo Valente, This is a semi-automatic email about new static checker warnings. The patch 24bfd19bb789: "block, bfq: update blkio stats outside the scheduler lock" from Nov 13, 2017, leads to the following Smatch complaint: block/bfq-iosched.c:5013 __bfq_insert_request() error: we previously assumed 'bfqq' could be null (see line 5008) block/bfq-iosched.c 5007 5008 waiting = bfqq && bfq_bfqq_wait_request(bfqq); ^^^^ The patch adds a NULL check here. Hopefully it's not required because 5009 bfq_add_request(rq); 5010 idle_timer_disabled = waiting && !bfq_bfqq_wait_request(bfqq); 5011 5012 rq->fifo_time = ktime_get_ns() + bfqd->bfq_fifo_expire[rq_is_sync(rq)]; 5013 list_add_tail(&rq->queuelist, &bfqq->fifo); ^^^^^^^^^^^ the existing code assumes "bfqq" is valid. 5014 5015 bfq_rq_enqueued(bfqd, bfqq, rq); regards, dan carpenter