From patchwork Thu Jun 16 16:17:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xianting Tian X-Patchwork-Id: 12884424 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0239ACCA481 for ; Thu, 16 Jun 2022 16:18:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 114696B0085; Thu, 16 Jun 2022 12:17:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0721B6B0087; Thu, 16 Jun 2022 12:17:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E7BC86B0089; Thu, 16 Jun 2022 12:17:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id CA9DB6B0087 for ; Thu, 16 Jun 2022 12:17:58 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay12.hostedemail.com (Postfix) with ESMTP id AAA601204EE for ; Thu, 16 Jun 2022 16:17:58 +0000 (UTC) X-FDA: 79584605436.17.70F591A Received: from out30-45.freemail.mail.aliyun.com (out30-45.freemail.mail.aliyun.com [115.124.30.45]) by imf04.hostedemail.com (Postfix) with ESMTP id E82B940082 for ; Thu, 16 Jun 2022 16:17:57 +0000 (UTC) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R131e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045168;MF=xianting.tian@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0VGamLOd_1655396273; Received: from localhost(mailfrom:xianting.tian@linux.alibaba.com fp:SMTPD_---0VGamLOd_1655396273) by smtp.aliyun-inc.com; Fri, 17 Jun 2022 00:17:54 +0800 From: Xianting Tian To: akpm@linux-foundation.org, ziy@nvidia.com, gregkh@linuxfoundation.org, stable@vger.kernel.org, guoren@kernel.org Cc: huanyi.xj@alibaba-inc.com, guohanjun@huawei.com, zjb194813@alibaba-inc.com, tianhu.hh@alibaba-inc.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xianting Tian Subject: [PATCH 5.15] mm: validate buddy page before using Date: Fri, 17 Jun 2022 00:17:45 +0800 Message-Id: <20220616161746.3565225-6-xianting.tian@linux.alibaba.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220616161746.3565225-1-xianting.tian@linux.alibaba.com> References: <20220616161746.3565225-1-xianting.tian@linux.alibaba.com> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655396278; a=rsa-sha256; cv=none; b=tVFSggEjdO/0amwZAXx9EDoa6JCN3Tvi98MUpLbrEsheg01TecymftRMAPr/AC68rJg9bi 4bp+vIkgvCSg7A1niQE1PDKunEPJGfhSHXuC8NNdPlmxKYXfzCX9qmh1cklg+MpNnGDWhO hWeNxAciXzzV+/jLxQ4wm9fAKthyMHY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655396278; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=wmijmlmq4m2eVOBJUQj8lExjww4R7+dUQd0cWgqUF0A=; b=O94DJuXqLHJHmTtQAjO3uwBYUMeVV509EIn72EbvQe0a0HfF1+1dVtJ45j6hA21ZVyBDRR 3RRKhPocV5mhebuxcOOYW7V0g5kSjDdTuIgJu2WpWMba0KH4sWP886dnwZR41C5pb/NE4h FjvcJS87J5HeTAAiNF1xS3r9CEydOkE= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=alibaba.com; spf=pass (imf04.hostedemail.com: domain of xianting.tian@linux.alibaba.com designates 115.124.30.45 as permitted sender) smtp.mailfrom=xianting.tian@linux.alibaba.com Authentication-Results: imf04.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=alibaba.com; spf=pass (imf04.hostedemail.com: domain of xianting.tian@linux.alibaba.com designates 115.124.30.45 as permitted sender) smtp.mailfrom=xianting.tian@linux.alibaba.com X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: E82B940082 X-Stat-Signature: 9ry157gnkuzfkyffhmggto9eoodqek6x X-HE-Tag: 1655396277-981131 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: Commit 787af64d05cd ("mm: page_alloc: validate buddy before check its migratetype.") fixes a bug in 1dd214b8f21c and there is a similar bug in d9dddbf55667 that can be fixed in a similar way too. In unset_migratetype_isolate(), we also need the fix, so move page_is_buddy() from mm/page_alloc.c to mm/internal.h In addition, for RISC-V arch the first 2MB RAM could be reserved for opensbi, so it would have pfn_base=512 and mem_map began with 512th PFN when CONFIG_FLATMEM=y. But __find_buddy_pfn algorithm thinks the start pfn 0, it could get 0 pfn or less than the pfn_base value. We need page_is_buddy() to verify the buddy to prevent accessing an invalid buddy. Fixes: d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and other pageblocks") Cc: stable@vger.kernel.org Reported-by: zjb194813@alibaba-inc.com Reported-by: tianhu.hh@alibaba-inc.com Signed-off-by: Xianting Tian --- mm/internal.h | 34 ++++++++++++++++++++++++++++++++++ mm/page_alloc.c | 37 +++---------------------------------- mm/page_isolation.c | 3 ++- 3 files changed, 39 insertions(+), 35 deletions(-) diff --git a/mm/internal.h b/mm/internal.h index cf3cb933eba3..e838d825cfaa 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -340,6 +340,40 @@ static inline bool is_data_mapping(vm_flags_t flags) return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) == VM_WRITE; } +/* + * This function checks whether a page is free && is the buddy + * we can coalesce a page and its buddy if + * (a) the buddy is not in a hole (check before calling!) && + * (b) the buddy is in the buddy system && + * (c) a page and its buddy have the same order && + * (d) a page and its buddy are in the same zone. + * + * For recording whether a page is in the buddy system, we set PageBuddy. + * Setting, clearing, and testing PageBuddy is serialized by zone->lock. + * + * For recording page's order, we use page_private(page). + */ +static inline bool page_is_buddy(struct page *page, struct page *buddy, + unsigned int order) +{ + if (!page_is_guard(buddy) && !PageBuddy(buddy)) + return false; + + if (buddy_order(buddy) != order) + return false; + + /* + * zone check is done late to avoid uselessly calculating + * zone/node ids for pages that could never merge. + */ + if (page_zone_id(page) != page_zone_id(buddy)) + return false; + + VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy); + + return true; +} + /* mm/util.c */ void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *prev); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a0b7afae59e9..8a29c0ff1c7b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -875,40 +875,6 @@ static inline void set_buddy_order(struct page *page, unsigned int order) __SetPageBuddy(page); } -/* - * This function checks whether a page is free && is the buddy - * we can coalesce a page and its buddy if - * (a) the buddy is not in a hole (check before calling!) && - * (b) the buddy is in the buddy system && - * (c) a page and its buddy have the same order && - * (d) a page and its buddy are in the same zone. - * - * For recording whether a page is in the buddy system, we set PageBuddy. - * Setting, clearing, and testing PageBuddy is serialized by zone->lock. - * - * For recording page's order, we use page_private(page). - */ -static inline bool page_is_buddy(struct page *page, struct page *buddy, - unsigned int order) -{ - if (!page_is_guard(buddy) && !PageBuddy(buddy)) - return false; - - if (buddy_order(buddy) != order) - return false; - - /* - * zone check is done late to avoid uselessly calculating - * zone/node ids for pages that could never merge. - */ - if (page_zone_id(page) != page_zone_id(buddy)) - return false; - - VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy); - - return true; -} - #ifdef CONFIG_COMPACTION static inline struct capture_control *task_capc(struct zone *zone) { @@ -1118,6 +1084,9 @@ static inline void __free_one_page(struct page *page, buddy_pfn = __find_buddy_pfn(pfn, order); buddy = page + (buddy_pfn - pfn); + + if (!page_is_buddy(page, buddy, order)) + goto done_merging; buddy_mt = get_pageblock_migratetype(buddy); if (migratetype != buddy_mt diff --git a/mm/page_isolation.c b/mm/page_isolation.c index a95c2c6562d0..70c1870e786b 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -93,7 +93,8 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype) buddy_pfn = __find_buddy_pfn(pfn, order); buddy = page + (buddy_pfn - pfn); - if (!is_migrate_isolate_page(buddy)) { + if (page_is_buddy(page, buddy, order) && + !is_migrate_isolate_page(buddy)) { __isolate_free_page(page, order); isolated_page = true; }