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,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT autolearn=unavailable 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 A1B81C48BC5 for ; Wed, 19 Jun 2019 20:11:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 677D02084A for ; Wed, 19 Jun 2019 20:11:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560975100; bh=ufGXvlZ2oTEKufBzdv5TWcAajgtSj8R8w3ocK3xoc6o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Jv/boilYskDiMIdAmKYKfCnasNXpge8xL7NmTfDBJv6jUScKfICaY150z2WOA8AJR VbzCiO+prACxptDG+hufe4L4TNjJoUasenkQX8lQV8SWMCoWHFb4zHeGyGfiSma+Xl jDxmEoNs6ZwD1bffWXWI1QItsOjIxUSm9LxsUAUU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729988AbfFSULj (ORCPT ); Wed, 19 Jun 2019 16:11:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:58482 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726175AbfFSULi (ORCPT ); Wed, 19 Jun 2019 16:11:38 -0400 Received: from localhost (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (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 9A2E52084A; Wed, 19 Jun 2019 20:11:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560975098; bh=ufGXvlZ2oTEKufBzdv5TWcAajgtSj8R8w3ocK3xoc6o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=n/P2ytqoa4CHBYW0h3D8zdoeGL6fXEhsCbYD1mjWA0M9en9jRSvjyLvTNAxxmXn8m wegd9U4u1hMoQHEs+mxLfEfCJVonMmLE8zqmKWViZ2GoVdW28j2rqbIaDsCRaWy+dP 77Y974gtUinTHbNigAOz4ddSSxCc3iPmW9N5KL2Q= Date: Wed, 19 Jun 2019 16:11:36 -0400 From: Sasha Levin To: Jan Kara Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, syzbot+10007d66ca02b08f0e60@syzkaller.appspotmail.com, Jens Axboe , linux-block@vger.kernel.org Subject: Re: [PATCH AUTOSEL 5.1 35/70] loop: Don't change loop device under exclusive opener Message-ID: <20190619201136.GD2226@sasha-vm> References: <20190608113950.8033-1-sashal@kernel.org> <20190608113950.8033-35-sashal@kernel.org> <20190610090013.GF12765@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20190610090013.GF12765@quack2.suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 10, 2019 at 11:00:13AM +0200, Jan Kara wrote: >On Sat 08-06-19 07:39:14, Sasha Levin wrote: >> From: Jan Kara >> >> [ Upstream commit 33ec3e53e7b1869d7851e59e126bdb0fe0bd1982 ] > >Please don't push this to stable kernels because... I've dropped this, but... >> [Deliberately chosen not to CC stable as a user with priviledges to >> trigger this race has other means of taking the system down and this >> has a potential of breaking some weird userspace setup] > >... of this. Thanks! Can't this be triggered by an "innocent" user, rather as part of an attack? Why can't this race happen during regular usage? -- Thanks, Sasha