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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 7119AC433E0 for ; Thu, 4 Mar 2021 21:17:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EB5FD65007 for ; Thu, 4 Mar 2021 21:17:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EB5FD65007 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2FDCE6B0005; Thu, 4 Mar 2021 16:17:12 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2ADA76B0006; Thu, 4 Mar 2021 16:17:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 150B76B0007; Thu, 4 Mar 2021 16:17:12 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0222.hostedemail.com [216.40.44.222]) by kanga.kvack.org (Postfix) with ESMTP id EAA416B0005 for ; Thu, 4 Mar 2021 16:17:11 -0500 (EST) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id A90628249980 for ; Thu, 4 Mar 2021 21:17:11 +0000 (UTC) X-FDA: 77883452262.30.8E56CAE Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf05.hostedemail.com (Postfix) with ESMTP id 7BD5EE00010A for ; Thu, 4 Mar 2021 21:17:10 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1614892629; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=/tZ880Yp/AKHzG1rpWeDp9V30VjIiNL6pvc/O/61Sck=; b=nCoW2/W4dLR8+pG1rRhirVZ+Z9b+K4gJulKogHhl2KxAUI3Q1MY/2G1W7U3tCZTIOMpHPF 5vl7YKo1McvzNVmkXuYzU77vtyz+lrpGiKEy9WprGWE8uPhkWUWnlXAT64Z9QIcOQJ276K hQIubeeMqKJtIEjp+l2+3+97NKjOUi8= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 88BD6AFB0; Thu, 4 Mar 2021 21:17:09 +0000 (UTC) Date: Thu, 4 Mar 2021 22:17:08 +0100 From: Anthony Iliopoulos To: Greg Kroah-Hartman Cc: Jens Axboe , Andrew Morton , Matthew Wilcox , stable@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH STABLE 5.10 5.11] swap: fix swapfile page to sector mapping Message-ID: References: <20210304150824.29878-1-ailiop@suse.com> <20210304150824.29878-5-ailiop@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: rtbby7yudx4dk6mmn1ffe6pq984pjrsm X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 7BD5EE00010A Received-SPF: none (suse.com>: No applicable sender policy available) receiver=imf05; identity=mailfrom; envelope-from=""; helo=mx2.suse.de; client-ip=195.135.220.15 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614892630-309277 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Mar 04, 2021 at 05:58:49PM +0100, Greg Kroah-Hartman wrote: > On Thu, Mar 04, 2021 at 05:30:00PM +0100, Anthony Iliopoulos wrote: > > On Thu, Mar 04, 2021 at 04:16:26PM +0100, Greg Kroah-Hartman wrote: > > > On Thu, Mar 04, 2021 at 04:08:24PM +0100, Anthony Iliopoulos wrote: > > > > commit caf6912f3f4af7232340d500a4a2008f81b93f14 upstream. > > > > > > No, this does not look like that commit. > > > > > > Why can I not just take caf6912f3f4a ("swap: fix swapfile read/write > > > offset") directly for 5.10 and 5.11? WHat has changed to prevent that? > > > > You're right of course, the upstream fix applies even on v5.4 so you > > could just take it directly for those branches if this is preferable. > > But, that commit says it fixes 48d15436fde6 ("mm: remove get_swap_bio"), > which is NOT what you are saying here in these patches. It is admittedly a bit confusing as the upstream commit fixes two issues in one swoop: - the bug which was introduced in v5.12-rc1 via 48d15436fde6 ("mm: remove get_swap_bio"), which affected swapfiles running on regular block devices, in addition to: - an identical bug which up until 48d15436fde6 was only applicable to swapfiles on top of blockdevs that can do page io without the block layer, which was introduced with dd6bd0d9c7db ("swap: use bdev_read_page() / bdev_write_page()") > So which is it? Is there a problem in 5.11 and older kernels > (48d15436fde6 ("mm: remove get_swap_bio") showed up in 5.12-rc1), that > requires this fix, or is there nothing needed to be backported? The second point/bug mentioned above is present on 5.11 and all older kernels, so some form of this fix is required. > As a note, I've been running swapfiles on 5.11 and earlier just fine for > a very long time now, so is this really an issue? Yes there is an issue on all kernels since v3.16-rc1 when dd6bd0d9c7db was introduced, but it is applicable only to setups with swapfiles on filesystems sitting on top of brd, zram, btt or pmem. I can trivially reproduce this e.g. on v5.11 by creating a swapfile on top of a zram or pmem blockdev and pushing the system to swap out pages, at which point it corrupts filesystem blocks that don't belong to the swapfile. Regards, Anthony