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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5306DCCA47E for ; Thu, 16 Jun 2022 16:18:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C38746B0083; Thu, 16 Jun 2022 12:17:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BEF6F6B0085; 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 A870D6B0088; Thu, 16 Jun 2022 12:17:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 980056B0085 for ; Thu, 16 Jun 2022 12:17:58 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 7134D214E3 for ; Thu, 16 Jun 2022 16:17:58 +0000 (UTC) X-FDA: 79584605436.03.4C99067 Received: from out30-57.freemail.mail.aliyun.com (out30-57.freemail.mail.aliyun.com [115.124.30.57]) by imf18.hostedemail.com (Postfix) with ESMTP id B62BE1C0088 for ; Thu, 16 Jun 2022 16:17:56 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R651e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046049;MF=xianting.tian@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0VGaoY3U_1655396267; Received: from localhost(mailfrom:xianting.tian@linux.alibaba.com fp:SMTPD_---0VGaoY3U_1655396267) by smtp.aliyun-inc.com; Fri, 17 Jun 2022 00:17:48 +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] mm: page_alloc: validate buddy page before using Date: Fri, 17 Jun 2022 00:17:40 +0800 Message-Id: <20220616161746.3565225-1-xianting.tian@linux.alibaba.com> X-Mailer: git-send-email 2.17.1 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655396277; a=rsa-sha256; cv=none; b=m22TqZN8oW51uu3LaPUzm4ESZtuhoc4JJeVXnN5mfzx+vRelJeCLYhq+2rL75q64OLFMy3 PPSyrXjlqJa/Zyc3UkSmI0PLz7l24ivWW+fcObT8XXrgBz2iMMmX9fZhy0c4JB7Tnq9xOC 2GHlYkBzf4FvL9DOFkFXoDd8K9K/1Z8= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655396277; 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:references; bh=SF4R3KgDCTd6hsXxnQcoKVQtQFiigx2kvPGScaqqh/o=; b=EKSiphM4J8XWDvDZ9M3Aw0VxcPXopaTMiFqaSjrYYJZ5spNotLTD5e3wHO4XbJAz98mWks vaxUZK7giQ7bMkHFVo/xJNjniLdNwUQ1W/sPtqDcwH3gDj/IYpEXaUcn7MsEmNr4R5QwBR AEZD8mqISTga2GG0XHsxoeZfCPYPfHw= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=alibaba.com; spf=pass (imf18.hostedemail.com: domain of xianting.tian@linux.alibaba.com designates 115.124.30.57 as permitted sender) smtp.mailfrom=xianting.tian@linux.alibaba.com Authentication-Results: imf18.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=alibaba.com; spf=pass (imf18.hostedemail.com: domain of xianting.tian@linux.alibaba.com designates 115.124.30.57 as permitted sender) smtp.mailfrom=xianting.tian@linux.alibaba.com X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: B62BE1C0088 X-Stat-Signature: pgofrunbyrmjf9trqjdyigbo9n8jyscg X-HE-Tag: 1655396276-984053 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 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/page_alloc.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a6e682569e5b..1c423faa4b62 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -864,6 +864,9 @@ static inline void __free_one_page(struct page *page, buddy_idx = __find_buddy_index(page_idx, order); buddy = page + (buddy_idx - page_idx); + + if (!page_is_buddy(page, buddy, order)) + goto done_merging; buddy_mt = get_pageblock_migratetype(buddy); if (migratetype != buddy_mt -- 2.17.1