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=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 5B962C04EB8 for ; Mon, 10 Dec 2018 16:17:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 205592082F for ; Mon, 10 Dec 2018 16:17:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 205592082F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-block-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726900AbeLJQRH (ORCPT ); Mon, 10 Dec 2018 11:17:07 -0500 Received: from mail-qt1-f193.google.com ([209.85.160.193]:44841 "EHLO mail-qt1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726649AbeLJQRH (ORCPT ); Mon, 10 Dec 2018 11:17:07 -0500 Received: by mail-qt1-f193.google.com with SMTP id n32so12856923qte.11 for ; Mon, 10 Dec 2018 08:17:06 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=sLCZ/dfizqcpzJOJ82nnvzaSVI6NoLk/H1vjEmCHydg=; b=tx38AFrHHZZ3NFEs6dEuDcx75JShP1W1JKK851lx6sFn/1Tz2gp3vQqMAdC33S6z/C ezpQkt1FOCfv1nkhc/MkGZAUzIzDRpa4NtFiBovWyGWcRc3zMpSCR3aYYQkGNlKDl20H rdZQw4dFBA74FUS4wDisckcGl3OARtRmVp3L/CSvCeO3/dwRK2Vjh7gt4hg7DbUcFX/U qjxnkMSMcnPvnGTDwbOyNBMtU4AQFpzSa9ru+FqzkmPet6fFP1Jnzq388Dmz+XekJ93i hwCEosj7hOQ3Vwq4WvgUraiSP+9+FCO+f7H0hkFgaYg0JTOlfW++OD1T8UDsP0TpzbFo X2uA== X-Gm-Message-State: AA+aEWZGShhyNW34QlmGwluwfwDvUgcpA8Hb9nDlQEjf9ssOFxw9XTR1 Y6A4EZUlO1yu4KhIQcD//DJnFA== X-Google-Smtp-Source: AFSGD/VOAdKHjcH0i0WGdeOC6hAlPNdTwIKKVSZp1PXxsCv00LV54VVkhUO4twe+B77KpAn8Rw1/XA== X-Received: by 2002:a0c:f74c:: with SMTP id e12mr12195090qvo.26.1544458626309; Mon, 10 Dec 2018 08:17:06 -0800 (PST) Received: from loberhel74 (035-134-022-126.static.chtrptr.net. [35.134.22.126]) by smtp.gmail.com with ESMTPSA id b20sm8162852qkb.17.2018.12.10.08.17.05 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 10 Dec 2018 08:17:05 -0800 (PST) Message-ID: <1544458624.18488.2.camel@redhat.com> Subject: Re: [PATCH] block: Restore tape support From: Laurence Oberman To: Jens Axboe , Keith Busch , Bart Van Assche Cc: linux-block@vger.kernel.org, Christoph Hellwig , Todd Aiken , stable@vger.kernel.org Date: Mon, 10 Dec 2018 11:17:04 -0500 In-Reply-To: <93112026-a6b3-6db4-0c74-afbbbf6ca493@kernel.dk> References: <20181210030814.13235-1-bvanassche@acm.org> <20181210153230.GB25206@localhost.localdomain> <93112026-a6b3-6db4-0c74-afbbbf6ca493@kernel.dk> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6 (3.22.6-10.el7) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Mon, 2018-12-10 at 08:36 -0700, Jens Axboe wrote: > On 12/10/18 8:32 AM, Keith Busch wrote: > > On Sun, Dec 09, 2018 at 07:08:14PM -0800, Bart Van Assche wrote: > > > According to what I found in > > > https://bugzilla.kernel.org/show_bug.cgi?id=201935 patch "block: > > > Clear > > > kernel memory before copying to user" broke tape access. Hence > > > revert > > > that patch. > > > > Instead of reverting back to the leaking arbitrary kernel memory, > > why > > not just make a fix on top of it? This should do it: > > > > --- > > diff --git a/block/bio.c b/block/bio.c > > index c4ef8aa46452..55a5386fd431 100644 > > --- a/block/bio.c > > +++ b/block/bio.c > > @@ -1262,7 +1262,8 @@ struct bio *bio_copy_user_iov(struct > > request_queue *q, > >   if (ret) > >   goto cleanup; > >   } else { > > - zero_fill_bio(bio); > > + if (bmd->is_our_pages) > > + zero_fill_bio(bio); > >   iov_iter_advance(iter, bio->bi_iter.bi_size); > >   } > >   > > That should be fine, the other case is user mapped memory anyway. > OK, I will test this today Thanks folks!! Laurence