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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FAKE_REPLY_C,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,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 CBA03C3F2CD for ; Mon, 2 Mar 2020 20:41:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7F7F72467B for ; Mon, 2 Mar 2020 20:41:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583181661; bh=zSZieL+ySgARgxDZJBIGKZWYvrkE3mow+cIkXNqm8vY=; h=Date:From:To:Cc:Subject:In-Reply-To:List-ID:From; b=gHm8vQ15nCddIhfw3Blwg6iYnBUXJnDnqAKR0HE3OOr6xlauo99Fb9zf1WHlsxnR2 oWUGpt7+wmOxzkq5rL30NpUGq2IgZqnyEkXLMuE3qhXcsG/ZhKCDTR3aimN9rUNw31 +lUCbGw1+Jjdh4jHvhH5DixOv+NP7sHQSMrDCKcc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726561AbgCBUlA (ORCPT ); Mon, 2 Mar 2020 15:41:00 -0500 Received: from mail.kernel.org ([198.145.29.99]:45486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725781AbgCBUlA (ORCPT ); Mon, 2 Mar 2020 15:41:00 -0500 Received: from localhost (mobile-166-175-186-165.mycingular.net [166.175.186.165]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E418D21556; Mon, 2 Mar 2020 20:40:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583181660; bh=zSZieL+ySgARgxDZJBIGKZWYvrkE3mow+cIkXNqm8vY=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=C4voe7XGggq/F6m83iCejst5Rs6NqGAz2JSGplquylZwgyZLgiV4Y8dQhjHeiph2D HrM1Jwp+fMdL1McWdTesnxZHujjS07JllPD0Z/LihIAbvKGzbcDDrzBTM5LokmCA6E fGR94NVikZp6rraG8LoQPvGo7RfrHWPL8gFMnyDY= Date: Mon, 2 Mar 2020 14:40:57 -0600 From: Bjorn Helgaas To: Jan Kara Cc: Jens Axboe , linux-block@vger.kernel.org, tristmd@gmail.com, stable@vger.kernel.org Subject: Re: [PATCH] blktrace: Protect q->blk_trace with RCU Message-ID: <20200302204057.GA128531@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200206142812.25989-1-jack@suse.cz> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Thu, Feb 06, 2020 at 03:28:12PM +0100, Jan Kara wrote: > @@ -1844,18 +1896,18 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev, > } > > ret = 0; > - if (q->blk_trace == NULL) > + if (bt == NULL) > ret = blk_trace_setup_queue(q, bdev); > > if (ret == 0) { > if (attr == &dev_attr_act_mask) > - q->blk_trace->act_mask = value; > + bt->act_mask = value; You've likely seen this already, but Coverity complains that "bt" may be a NULL pointer here, since we checked it for NULL above. CID 1460458: Null pointer dereferences (FORWARD_NULL) > else if (attr == &dev_attr_pid) > - q->blk_trace->pid = value; > + bt->pid = value; > else if (attr == &dev_attr_start_lba) > - q->blk_trace->start_lba = value; > + bt->start_lba = value; > else if (attr == &dev_attr_end_lba) > - q->blk_trace->end_lba = value; > + bt->end_lba = value; > } > > out_unlock_bdev: >