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[23.128.96.18]) by mx.google.com with ESMTP id m20si48561edv.175.2021.03.04.09.52.19; Thu, 04 Mar 2021 09:52:42 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@suse.com header.s=susede1 header.b=bTsJtxWW; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=NONE dis=NONE) header.from=suse.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233477AbhCDPHC (ORCPT + 99 others); Thu, 4 Mar 2021 10:07:02 -0500 Received: from mx2.suse.de ([195.135.220.15]:53228 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233020AbhCDPGn (ORCPT ); Thu, 4 Mar 2021 10:06:43 -0500 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=1614870357; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jBnOPVs2uTng8H0DGAIsGwKWTXMxqhIgOJPERVKaJAM=; b=bTsJtxWW5+yBw32grcqtUQsA8wP82b4g8ZvJi+I7jSxwrIyHBR2raS2JEpdsCgv5+OFBpQ ROXoMQz6z4PbahUf0Womwg4Z5bAlVgrUcfQh7HZbRRZKM5bFelk393bmLl3VvsxCdURG+j xix78kmjnnJdozxR8xd1+B/H8L142Mo= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 45305AE14; Thu, 4 Mar 2021 15:05:57 +0000 (UTC) From: Anthony Iliopoulos To: Greg Kroah-Hartman , Jens Axboe , Andrew Morton , Matthew Wilcox Cc: stable@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH STABLE 4.9] swap: fix swapfile page to sector mapping Date: Thu, 4 Mar 2021 16:08:23 +0100 Message-Id: <20210304150824.29878-4-ailiop@suse.com> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210304150824.29878-1-ailiop@suse.com> References: <20210304150824.29878-1-ailiop@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit caf6912f3f4af7232340d500a4a2008f81b93f14 upstream. Fix block device sector offset calculation for swap page io on top of blockdevs that provide a rw_page operation and do page-sized io directly (without the block layer). Currently swap_page_sector() maps a swap page into a blockdev sector by obtaining the swap page offset (swap map slot), but ignores the swapfile starting offset into the blockdev. In setups where swapfiles are sitting on top of a filesystem, this results into swapping out activity potentially overwriting filesystem blocks that fall outside the swapfile region. [This issue only affects swapfiles on filesystems on top of blockdevs that implement rw_page ops (brd, zram, btt, pmem), and not on top of any other block devices, in contrast to the upstream commit fix.] Fixes: dd6bd0d9c7db ("swap: use bdev_read_page() / bdev_write_page()") Cc: stable@vger.kernel.org # 4.9 Signed-off-by: Anthony Iliopoulos --- mm/page_io.c | 11 +++-------- mm/swapfile.c | 2 +- 2 files changed, 4 insertions(+), 9 deletions(-) diff --git a/mm/page_io.c b/mm/page_io.c index a2651f58c86a..ad0e0ce31090 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -32,7 +32,6 @@ static struct bio *get_swap_bio(gfp_t gfp_flags, bio = bio_alloc(gfp_flags, 1); if (bio) { bio->bi_iter.bi_sector = map_swap_page(page, &bio->bi_bdev); - bio->bi_iter.bi_sector <<= PAGE_SHIFT - 9; bio->bi_end_io = end_io; bio_add_page(bio, page, PAGE_SIZE, 0); @@ -252,11 +251,6 @@ int swap_writepage(struct page *page, struct writeback_control *wbc) return ret; } -static sector_t swap_page_sector(struct page *page) -{ - return (sector_t)__page_file_index(page) << (PAGE_SHIFT - 9); -} - int __swap_writepage(struct page *page, struct writeback_control *wbc, bio_end_io_t end_write_func) { @@ -306,7 +300,8 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc, return ret; } - ret = bdev_write_page(sis->bdev, swap_page_sector(page), page, wbc); + ret = bdev_write_page(sis->bdev, map_swap_page(page, &sis->bdev), + page, wbc); if (!ret) { count_vm_event(PSWPOUT); return 0; @@ -357,7 +352,7 @@ int swap_readpage(struct page *page) return ret; } - ret = bdev_read_page(sis->bdev, swap_page_sector(page), page); + ret = bdev_read_page(sis->bdev, map_swap_page(page, &sis->bdev), page); if (!ret) { if (trylock_page(page)) { swap_slot_free_notify(page); diff --git a/mm/swapfile.c b/mm/swapfile.c index 855f62ab8c1b..8a0d969a6ebd 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1666,7 +1666,7 @@ sector_t map_swap_page(struct page *page, struct block_device **bdev) { swp_entry_t entry; entry.val = page_private(page); - return map_swap_entry(entry, bdev); + return map_swap_entry(entry, bdev) << (PAGE_SHIFT - 9); } /* -- 2.30.1