From patchwork Mon Nov 5 15:04:01 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zaslonko Mikhail X-Patchwork-Id: 10668397 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4D63B1709 for ; Mon, 5 Nov 2018 15:04:20 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3DA0E29976 for ; Mon, 5 Nov 2018 15:04:20 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 31F1529A2C; Mon, 5 Nov 2018 15:04:20 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 98105299B7 for ; Mon, 5 Nov 2018 15:04:19 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9AE9E6B000A; Mon, 5 Nov 2018 10:04:18 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 95B466B000C; Mon, 5 Nov 2018 10:04:18 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 825F76B000D; Mon, 5 Nov 2018 10:04:18 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) by kanga.kvack.org (Postfix) with ESMTP id 2CACE6B000A for ; Mon, 5 Nov 2018 10:04:18 -0500 (EST) Received: by mail-ed1-f72.google.com with SMTP id x1-v6so5438193edh.8 for ; Mon, 05 Nov 2018 07:04:18 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:from:to:cc :subject:date:in-reply-to:references:message-id; bh=GSSm6xWsWkn9tWb14DnUelz8UtpxgNa9JxncWE3Rgos=; b=htg1dF11wcA7C02vchjWFJEVlrtlOQaPa9n9Wh6DOTCWpk0XjlKbaZAX7QPTL1T9Ql UBji4h7KsTg2Z5+Hb7Y9BHSfoV4sHcnYnVp5RjS6+z+q/s3DjCvuI1ozjWJegXG2PSot joHfIkuQo0mdTc3gzm22CDXmApms+QOC5qg6H2gUn7lBL9jfXs5JLZMHvB0GuBzXQA6/ rHy+4W8x/gwRaYi6byP365UCqE393DFn9qyzi6G1xvOiO6h8wSixoqogy9RjgZnzW0Om qhuPAnUJdPcVILoQ9MS6fSrYuXHy7k1gjlYUrSfT7yxmBKCGRwp8OClAWRkf4xxRLUj6 cKFg== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of zaslonko@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=zaslonko@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com X-Gm-Message-State: AGRZ1gLQsZbC3XE/lhSsHP/xsYMcG+sh3Zk2DWUbo7eXLx+omj8jiikx OYxwMMybtuLQI5tYbWE5Pxl4vJvk7p8RAP9vqm4JDNbMtFmrb09JjXEsnNk2UXks7wFekT7zoep IfeyIfrFZaLvLqhXJBGmb2CYihWU0HNq+vmPB5m7gRCC41BpAxA7BEKIaIRYP0qdWiw== X-Received: by 2002:a50:b393:: with SMTP id s19-v6mr10450184edd.241.1541430257678; Mon, 05 Nov 2018 07:04:17 -0800 (PST) X-Google-Smtp-Source: AJdET5cxMswbY1/AJXea+pzTei3okr44C0qSKpNKiTRd531Sb3GwtEpzfArhGegMaF7p3J9W68FD X-Received: by 2002:a50:b393:: with SMTP id s19-v6mr10450125edd.241.1541430256600; Mon, 05 Nov 2018 07:04:16 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1541430256; cv=none; d=google.com; s=arc-20160816; b=rkvDB4iQTdbfR3vz3iB0tBzM/NpV2J6uN3YuwXh18JIUmQhzb7MTDeAM6awrf/70GL VUApHkSaANyqCJyf8lp2xN+n6JjiNv/BUqkooM0pZeSBKt86+5ew+++4L3sHcrEFaw5U Ksll+EZ3bgCz2Z9S8DA5AtYB6q1x74zlijE3Jd3Bj6uTbwRBQrXgP/YCOFMAJVl3bdtS wGNHa6C5ELuDh7v5HTxvvnuM7c5K6L8k30mKmEX+6JK5NoNrWEo7cHn31UyjAhTKoCLv s+N9ko66FFqOQGz/KmCKEb4wpew14Tit9WyVKRHmUtFGdJGWRp08TS6d5y9lyPNgzrlh gGxg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:references:in-reply-to:date:subject:cc:to:from; bh=GSSm6xWsWkn9tWb14DnUelz8UtpxgNa9JxncWE3Rgos=; b=iqn/JyQCW61I92Eurx361skHERCKAedZz3j78At4coj66C4UAw+6sZYW4ackui5G+W u6akg7f729z4AS3QzabrnHrMJx+UDIwG9xLiYeS//SU3mWPQ0un/2DBoN/h8ngnad1ne IlR6L30kaoRjhOr5F17XFIJgzgQaAdCWH2DZUIPkTH5e4GZpvrtVUMnFfYp5b2CbLNfF q5ap4LoTx0bpJ0nD9ALh1zop1VRu5IXy3iej0NAjBsRzmt0mDZYLlXIBxv6gBdssXhW4 OLRur7I5ohrixxZiFXuZMXl9HxYrqq8v+zZ7isscLc5F8LCeYnvIK3bMmov8IjJBxRqx WEBQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of zaslonko@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=zaslonko@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com. [148.163.158.5]) by mx.google.com with ESMTPS id j2-v6si5490209ejj.39.2018.11.05.07.04.16 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 05 Nov 2018 07:04:16 -0800 (PST) Received-SPF: pass (google.com: domain of zaslonko@linux.ibm.com designates 148.163.158.5 as permitted sender) client-ip=148.163.158.5; Authentication-Results: mx.google.com; spf=pass (google.com: domain of zaslonko@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=zaslonko@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wA5F4Dhs026790 for ; Mon, 5 Nov 2018 10:04:15 -0500 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2njpgkdsmx-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 05 Nov 2018 10:04:14 -0500 Received: from localhost by e06smtp03.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 5 Nov 2018 15:04:07 -0000 Received: from b06cxnps3074.portsmouth.uk.ibm.com (9.149.109.194) by e06smtp03.uk.ibm.com (192.168.101.133) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 5 Nov 2018 15:04:04 -0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id wA5F43b144105744 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 5 Nov 2018 15:04:03 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EE434AE065; Mon, 5 Nov 2018 15:04:02 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A9E86AE045; Mon, 5 Nov 2018 15:04:02 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Mon, 5 Nov 2018 15:04:02 +0000 (GMT) From: Mikhail Zaslonko To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@kernel.org, Pavel.Tatashin@microsoft.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, gerald.schaefer@de.ibm.com, zaslonko@linux.ibm.com Subject: [PATCH v2 1/1] memory_hotplug: fix the panic when memory end is not on the section boundary Date: Mon, 5 Nov 2018 16:04:01 +0100 X-Mailer: git-send-email 2.16.4 In-Reply-To: <20181105150401.97287-1-zaslonko@linux.ibm.com> References: <20181105150401.97287-1-zaslonko@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18110515-0012-0000-0000-000002C3A4AA X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18110515-0013-0000-0000-000020F7E3E3 Message-Id: <20181105150401.97287-2-zaslonko@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-11-05_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1811050139 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: X-Virus-Scanned: ClamAV using ClamSMTP If memory end is not aligned with the sparse memory section boundary, the mapping of such a section is only partly initialized. This may lead to VM_BUG_ON due to uninitialized struct pages access from is_mem_section_removable() or test_pages_in_a_zone() function triggered by memory_hotplug sysfs handlers. Here are the the panic examples: CONFIG_DEBUG_VM_PGFLAGS=y kernel parameter mem=2050M -------------------------- page:000003d082008000 is uninitialized and poisoned page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) Call Trace: ([<0000000000385b26>] test_pages_in_a_zone+0xde/0x160) [<00000000008f15c4>] show_valid_zones+0x5c/0x190 [<00000000008cf9c4>] dev_attr_show+0x34/0x70 [<0000000000463ad0>] sysfs_kf_seq_show+0xc8/0x148 [<00000000003e4194>] seq_read+0x204/0x480 [<00000000003b53ea>] __vfs_read+0x32/0x178 [<00000000003b55b2>] vfs_read+0x82/0x138 [<00000000003b5be2>] ksys_read+0x5a/0xb0 [<0000000000b86ba0>] system_call+0xdc/0x2d8 Last Breaking-Event-Address: [<0000000000385b26>] test_pages_in_a_zone+0xde/0x160 Kernel panic - not syncing: Fatal exception: panic_on_oops CONFIG_DEBUG_VM_PGFLAGS=y kernel parameter mem=3075M -------------------------- page:000003d08300c000 is uninitialized and poisoned page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) Call Trace: ([<000000000038596c>] is_mem_section_removable+0xb4/0x190) [<00000000008f12fa>] show_mem_removable+0x9a/0xd8 [<00000000008cf9c4>] dev_attr_show+0x34/0x70 [<0000000000463ad0>] sysfs_kf_seq_show+0xc8/0x148 [<00000000003e4194>] seq_read+0x204/0x480 [<00000000003b53ea>] __vfs_read+0x32/0x178 [<00000000003b55b2>] vfs_read+0x82/0x138 [<00000000003b5be2>] ksys_read+0x5a/0xb0 [<0000000000b86ba0>] system_call+0xdc/0x2d8 Last Breaking-Event-Address: [<000000000038596c>] is_mem_section_removable+0xb4/0x190 Kernel panic - not syncing: Fatal exception: panic_on_oops This fix checks if the page lies within the zone boundaries before accessing the struct page data. The check is added to both functions. Signed-off-by: Mikhail Zaslonko Reviewed-by: Gerald Schaefer Cc: --- mm/memory_hotplug.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 38d94b703e9d..8402e70f74c2 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1229,9 +1229,8 @@ static struct page *next_active_pageblock(struct page *page) return page + pageblock_nr_pages; } -static bool is_pageblock_removable_nolock(struct page *page) +static bool is_pageblock_removable_nolock(struct page *page, struct zone **zone) { - struct zone *zone; unsigned long pfn; /* @@ -1241,15 +1240,14 @@ static bool is_pageblock_removable_nolock(struct page *page) * We have to take care about the node as well. If the node is offline * its NODE_DATA will be NULL - see page_zone. */ - if (!node_online(page_to_nid(page))) - return false; - - zone = page_zone(page); pfn = page_to_pfn(page); - if (!zone_spans_pfn(zone, pfn)) + if (*zone && !zone_spans_pfn(*zone, pfn)) return false; + if (!node_online(page_to_nid(page))) + return false; + *zone = page_zone(page); - return !has_unmovable_pages(zone, page, 0, MIGRATE_MOVABLE, true); + return !has_unmovable_pages(*zone, page, 0, MIGRATE_MOVABLE, true); } /* Checks if this range of memory is likely to be hot-removable. */ @@ -1257,10 +1255,11 @@ bool is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) { struct page *page = pfn_to_page(start_pfn); struct page *end_page = page + nr_pages; + struct zone *zone = NULL; /* Check the starting page of each pageblock within the range */ for (; page < end_page; page = next_active_pageblock(page)) { - if (!is_pageblock_removable_nolock(page)) + if (!is_pageblock_removable_nolock(page, &zone)) return false; cond_resched(); } @@ -1296,6 +1295,9 @@ int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn, i++; if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn) continue; + /* Check if we got outside of the zone */ + if (zone && !zone_spans_pfn(zone, pfn + i)) + return 0; page = pfn_to_page(pfn + i); if (zone && page_zone(page) != zone) return 0;