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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9542FC7EE23 for ; Thu, 1 Jun 2023 06:19:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231351AbjFAGTF (ORCPT ); Thu, 1 Jun 2023 02:19:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230473AbjFAGTE (ORCPT ); Thu, 1 Jun 2023 02:19:04 -0400 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6526CE2; Wed, 31 May 2023 23:19:02 -0700 (PDT) Received: by verein.lst.de (Postfix, from userid 2407) id 194B267373; Thu, 1 Jun 2023 08:18:59 +0200 (CEST) Date: Thu, 1 Jun 2023 08:18:58 +0200 From: Christoph Hellwig To: Yu Kuai Cc: Christoph Hellwig , axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, yangerkun@huawei.com, "yukuai (C)" Subject: Re: [PATCH -next v2] block: fix blktrace debugfs entries leak Message-ID: <20230601061858.GA24071@lst.de> References: <20230531092606.3037560-1-yukuai1@huaweicloud.com> <20230531124404.GA27412@lst.de> <509bcea6-21f6-3f64-01c3-02215955283d@huaweicloud.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <509bcea6-21f6-3f64-01c3-02215955283d@huaweicloud.com> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Thu, Jun 01, 2023 at 09:50:22AM +0800, Yu Kuai wrote: > Hi, Christoph > > 在 2023/05/31 20:44, Christoph Hellwig 写道: >> I like where this is going, but did you check that this doesn't >> introduce a potential crash with the current /dev/sg based blktrace? > > I just start to look at how /dev/sg is created and destroyed, however, > I'm confused here, do you mean that the added blk_trace_shutdown() here > might cause that /dev/sg blktrace to access freed momory or NULL > pointer? Yes. Given that __blk_trace_remove clears out q->blk_trace and frees the blk trace structure I'm worried about that.