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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 C2883C433E0 for ; Fri, 5 Jun 2020 14:42:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AB44B206DC for ; Fri, 5 Jun 2020 14:42:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728306AbgFEOmj (ORCPT ); Fri, 5 Jun 2020 10:42:39 -0400 Received: from mx2.suse.de ([195.135.220.15]:58088 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728007AbgFEOmi (ORCPT ); Fri, 5 Jun 2020 10:42:38 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 24986AAD0; Fri, 5 Jun 2020 14:42:40 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 4B4D41E1281; Fri, 5 Jun 2020 16:42:36 +0200 (CEST) Date: Fri, 5 Jun 2020 16:42:36 +0200 From: Jan Kara To: Dan Carpenter Cc: Jason Yan , Jan Kara , Markus Elfring , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, hulkci@huawei.com, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, Al Viro , Christoph Hellwig , Jens Axboe , Ming Lei Subject: Re: [PATCH v2] block: Fix use-after-free in blkdev_get() Message-ID: <20200605144236.GB13248@quack2.suse.cz> References: <88676ff2-cb7e-70ec-4421-ecf8318990b1@web.de> <5fa658bf-3028-9b5c-30cc-dbdef6bf8f7a@huawei.com> <20200605094353.GS30374@kadam> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200605094353.GS30374@kadam> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri 05-06-20 12:43:54, Dan Carpenter wrote: > I wonder if maybe the best fix is to re-add the "if (!res) " check back > to blkdev_get(). Well, it won't be that simple since we need to call bd_abort_claiming() under bdev->bd_mutex. And the fact that __blkdev_get() frees the reference you pass to it is somewhat subtle and surprising so I think we are better off getting rid of that. Honza -- Jan Kara SUSE Labs, CR