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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 C7582C43603 for ; Mon, 16 Dec 2019 18:02:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 93ADE21835 for ; Mon, 16 Dec 2019 18:02:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576519360; bh=pHMfLRRW7hQ+3bEIOX1BvLDlecxBjRJZdnD5T823sY8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=F8cYJFWU6TIrOzok18X0NinfgbUS2UVy9r4Ff3kLQ65hVPOWJG7YfSA6MePTWEOdM hbwqbBCCpgWnpCUOY327hLWVlFbTtCn0JkhTduH6l78rWJKGZ0OoO8K3YTtX55P9x0 Icu4UFzwJZ9fpv5qLmdAHmE8jN2RrUCB3jtVI+Yw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729373AbfLPSCj (ORCPT ); Mon, 16 Dec 2019 13:02:39 -0500 Received: from mail.kernel.org ([198.145.29.99]:38602 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729344AbfLPSCe (ORCPT ); Mon, 16 Dec 2019 13:02:34 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 93C21207FF; Mon, 16 Dec 2019 18:02:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576519353; bh=pHMfLRRW7hQ+3bEIOX1BvLDlecxBjRJZdnD5T823sY8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=b0q88tGbhcIZ7Qu9WtB2GkBz/3+31pxIpMmzV03m/TLVQT4VVoUS35RanaH9saEuK kgHoQ/hslHs97GCzRrsugYg0DEHguccXaIwcZhrsbv3XSF8t9HPbki1PDxVJhuoscy wDJD8C+VfeNYnOJoEUtBp+Qj2uaddc4+GwISXb9g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yumei Huang , "Michael S. Tsirkin" , Jason Wang , Jiang Liu , Andrew Morton , Igor Mammedov , virtualization@lists.linux-foundation.org, David Hildenbrand Subject: [PATCH 4.19 031/140] virtio-balloon: fix managed page counts when migrating pages between zones Date: Mon, 16 Dec 2019 18:48:19 +0100 Message-Id: <20191216174757.958746219@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191216174747.111154704@linuxfoundation.org> References: <20191216174747.111154704@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Hildenbrand commit 63341ab03706e11a31e3dd8ccc0fbc9beaf723f0 upstream. In case we have to migrate a ballon page to a newpage of another zone, the managed page count of both zones is wrong. Paired with memory offlining (which will adjust the managed page count), we can trigger kernel crashes and all kinds of different symptoms. One way to reproduce: 1. Start a QEMU guest with 4GB, no NUMA 2. Hotplug a 1GB DIMM and online the memory to ZONE_NORMAL 3. Inflate the balloon to 1GB 4. Unplug the DIMM (be quick, otherwise unmovable data ends up on it) 5. Observe /proc/zoneinfo Node 0, zone Normal pages free 16810 min 24848885473806 low 18471592959183339 high 36918337032892872 spanned 262144 present 262144 managed 18446744073709533486 6. Do anything that requires some memory (e.g., inflate the balloon some more). The OOM goes crazy and the system crashes [ 238.324946] Out of memory: Killed process 537 (login) total-vm:27584kB, anon-rss:860kB, file-rss:0kB, shmem-rss:00 [ 238.338585] systemd invoked oom-killer: gfp_mask=0x100cca(GFP_HIGHUSER_MOVABLE), order=0, oom_score_adj=0 [ 238.339420] CPU: 0 PID: 1 Comm: systemd Tainted: G D W 5.4.0-next-20191204+ #75 [ 238.340139] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu4 [ 238.341121] Call Trace: [ 238.341337] dump_stack+0x8f/0xd0 [ 238.341630] dump_header+0x61/0x5ea [ 238.341942] oom_kill_process.cold+0xb/0x10 [ 238.342299] out_of_memory+0x24d/0x5a0 [ 238.342625] __alloc_pages_slowpath+0xd12/0x1020 [ 238.343024] __alloc_pages_nodemask+0x391/0x410 [ 238.343407] pagecache_get_page+0xc3/0x3a0 [ 238.343757] filemap_fault+0x804/0xc30 [ 238.344083] ? ext4_filemap_fault+0x28/0x42 [ 238.344444] ext4_filemap_fault+0x30/0x42 [ 238.344789] __do_fault+0x37/0x1a0 [ 238.345087] __handle_mm_fault+0x104d/0x1ab0 [ 238.345450] handle_mm_fault+0x169/0x360 [ 238.345790] do_user_addr_fault+0x20d/0x490 [ 238.346154] do_page_fault+0x31/0x210 [ 238.346468] async_page_fault+0x43/0x50 [ 238.346797] RIP: 0033:0x7f47eba4197e [ 238.347110] Code: Bad RIP value. [ 238.347387] RSP: 002b:00007ffd7c0c1890 EFLAGS: 00010293 [ 238.347834] RAX: 0000000000000002 RBX: 000055d196a20a20 RCX: 00007f47eba4197e [ 238.348437] RDX: 0000000000000033 RSI: 00007ffd7c0c18c0 RDI: 0000000000000004 [ 238.349047] RBP: 00007ffd7c0c1c20 R08: 0000000000000000 R09: 0000000000000033 [ 238.349660] R10: 00000000ffffffff R11: 0000000000000293 R12: 0000000000000001 [ 238.350261] R13: ffffffffffffffff R14: 0000000000000000 R15: 00007ffd7c0c18c0 [ 238.350878] Mem-Info: [ 238.351085] active_anon:3121 inactive_anon:51 isolated_anon:0 [ 238.351085] active_file:12 inactive_file:7 isolated_file:0 [ 238.351085] unevictable:0 dirty:0 writeback:0 unstable:0 [ 238.351085] slab_reclaimable:5565 slab_unreclaimable:10170 [ 238.351085] mapped:3 shmem:111 pagetables:155 bounce:0 [ 238.351085] free:720717 free_pcp:2 free_cma:0 [ 238.353757] Node 0 active_anon:12484kB inactive_anon:204kB active_file:48kB inactive_file:28kB unevictable:0kB iss [ 238.355979] Node 0 DMA free:11556kB min:36kB low:48kB high:60kB reserved_highatomic:0KB active_anon:152kB inactivB [ 238.358345] lowmem_reserve[]: 0 2955 2884 2884 2884 [ 238.358761] Node 0 DMA32 free:2677864kB min:7004kB low:10028kB high:13052kB reserved_highatomic:0KB active_anon:0B [ 238.361202] lowmem_reserve[]: 0 0 72057594037927865 72057594037927865 72057594037927865 [ 238.361888] Node 0 Normal free:193448kB min:99395541895224kB low:73886371836733356kB high:147673348131571488kB reB [ 238.364765] lowmem_reserve[]: 0 0 0 0 0 [ 238.365101] Node 0 DMA: 7*4kB (U) 5*8kB (UE) 6*16kB (UME) 2*32kB (UM) 1*64kB (U) 2*128kB (UE) 3*256kB (UME) 2*512B [ 238.366379] Node 0 DMA32: 0*4kB 1*8kB (U) 2*16kB (UM) 2*32kB (UM) 2*64kB (UM) 1*128kB (U) 1*256kB (U) 1*512kB (U)B [ 238.367654] Node 0 Normal: 1985*4kB (UME) 1321*8kB (UME) 844*16kB (UME) 524*32kB (UME) 300*64kB (UME) 138*128kB (B [ 238.369184] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB [ 238.369915] 130 total pagecache pages [ 238.370241] 0 pages in swap cache [ 238.370533] Swap cache stats: add 0, delete 0, find 0/0 [ 238.370981] Free swap = 0kB [ 238.371239] Total swap = 0kB [ 238.371488] 1048445 pages RAM [ 238.371756] 0 pages HighMem/MovableOnly [ 238.372090] 306992 pages reserved [ 238.372376] 0 pages cma reserved [ 238.372661] 0 pages hwpoisoned In another instance (older kernel), I was able to observe this (negative page count :/): [ 180.896971] Offlined Pages 32768 [ 182.667462] Offlined Pages 32768 [ 184.408117] Offlined Pages 32768 [ 186.026321] Offlined Pages 32768 [ 187.684861] Offlined Pages 32768 [ 189.227013] Offlined Pages 32768 [ 190.830303] Offlined Pages 32768 [ 190.833071] Built 1 zonelists, mobility grouping on. Total pages: -36920272750453009 In another instance (older kernel), I was no longer able to start any process: [root@vm ~]# [ 214.348068] Offlined Pages 32768 [ 215.973009] Offlined Pages 32768 cat /proc/meminfo -bash: fork: Cannot allocate memory [root@vm ~]# cat /proc/meminfo -bash: fork: Cannot allocate memory Fix it by properly adjusting the managed page count when migrating if the zone changed. The managed page count of the zones now looks after unplug of the DIMM (and after deflating the balloon) just like before inflating the balloon (and plugging+onlining the DIMM). We'll temporarily modify the totalram page count. If this ever becomes a problem, we can fine tune by providing helpers that don't touch the totalram pages (e.g., adjust_zone_managed_page_count()). Please note that fixing up the managed page count is only necessary when we adjusted the managed page count when inflating - only if we don't have VIRTIO_BALLOON_F_DEFLATE_ON_OOM. With that feature, the managed page count is not touched when inflating/deflating. Reported-by: Yumei Huang Fixes: 3dcc0571cd64 ("mm: correctly update zone->managed_pages") Cc: # v3.11+ Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Jiang Liu Cc: Andrew Morton Cc: Igor Mammedov Cc: virtualization@lists.linux-foundation.org Signed-off-by: David Hildenbrand Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman --- drivers/virtio/virtio_balloon.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -468,6 +468,17 @@ static int virtballoon_migratepage(struc get_page(newpage); /* balloon reference */ + /* + * When we migrate a page to a different zone and adjusted the + * managed page count when inflating, we have to fixup the count of + * both involved zones. + */ + if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM) && + page_zone(page) != page_zone(newpage)) { + adjust_managed_page_count(page, 1); + adjust_managed_page_count(newpage, -1); + } + /* balloon's page migration 1st step -- inflate "newpage" */ spin_lock_irqsave(&vb_dev_info->pages_lock, flags); balloon_page_insert(vb_dev_info, newpage);