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 2C8A6C7619A for ; Thu, 23 Mar 2023 15:00:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231722AbjCWPAF (ORCPT ); Thu, 23 Mar 2023 11:00:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37540 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231609AbjCWPAE (ORCPT ); Thu, 23 Mar 2023 11:00:04 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A02C1F919 for ; Thu, 23 Mar 2023 08:00:01 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A4D4FB82142 for ; Thu, 23 Mar 2023 14:59:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4AABBC433D2; Thu, 23 Mar 2023 14:59:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1679583598; bh=X96U9cRa+WxlSwB3/wjzX6jxPtSOyXv5Ipj7ayZ3RAc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Bc+RPLy4dNSj/CE1trwGqvcjNNRpfzsFCzT3hGEjSBe5dNL4F/0w9RV3/l6JWEz4p R4S1PxgEIuqfWau3l/D5zjwOTpBXIRMgBrmYtTzDHOhnNC+SMMVss64ztz8XKA6UJB Izuv6ZRMAvWVYBWeY5qbfyACMS6xvv/tymQX6/iY9NYr0bWHOWGxfLjemJM7/hHlpZ WHHwWEcYzWMpintgX10SUA1xAcAZUg4NtM1WgmYr7tkBg0Xy0/+OS0JFpO5hPhTHlx FuI1g8fWdDrcl1ftfnSKlrLpsQBs9lDcSyZ/RR17L/fmyxQ5pN5/nFf/xwIadE/swS ogYLELjWa1CiA== Date: Thu, 23 Mar 2023 07:59:57 -0700 From: "Darrick J. Wong" To: Shiyang Ruan Cc: Andrew Morton , linux-fsdevel@vger.kernel.org, nvdimm@lists.linux.dev, dan.j.williams@intel.com, willy@infradead.org, jack@suse.cz Subject: Re: [PATCH] fsdax: unshare: zero destination if srcmap is HOLE or UNWRITTEN Message-ID: <20230323145957.GA466461@frogsfrogsfrogs> References: <1679483469-2-1-git-send-email-ruansy.fnst@fujitsu.com> <20230322160311.89efea3493db4c4ccad40a25@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Mar 23, 2023 at 02:50:38PM +0800, Shiyang Ruan wrote: > > > 在 2023/3/23 7:03, Andrew Morton 写道: > > On Wed, 22 Mar 2023 11:11:09 +0000 Shiyang Ruan wrote: > > > > > unshare copies data from source to destination. But if the source is > > > HOLE or UNWRITTEN extents, we should zero the destination, otherwise the > > > result will be unexpectable. > > > > Please provide much more detail on the user-visible effects of the bug. > > For example, are we leaking kernel memory contents to userspace? > > This fixes fail of generic/649. Please make a note of easy(ish) reproducers when you know about them, e.g. "Found by running generic/649 while mounting with -o dax=always on pmem." So that anyone scanning around for fix backports has an easier time doing an A/B comparison to assess whether or not they need the fix. Especially if there's any chance that person is you circa 2024. ;) --D > > -- > Thanks, > Ruan. > > > > > Thanks. > > > >