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 53051C433EF for ; Mon, 13 Jun 2022 14:12:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BCDBB8D0188; Mon, 13 Jun 2022 10:12:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B7C928D0171; Mon, 13 Jun 2022 10:12:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A43768D0188; Mon, 13 Jun 2022 10:12:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 947A58D0171 for ; Mon, 13 Jun 2022 10:12:03 -0400 (EDT) Received: from smtpin31.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay11.hostedemail.com (Postfix) with ESMTP id 020A081150 for ; Mon, 13 Jun 2022 14:12:02 +0000 (UTC) X-FDA: 79573401726.31.86AD3A9 Received: from out199-13.us.a.mail.aliyun.com (out199-13.us.a.mail.aliyun.com [47.90.199.13]) by imf01.hostedemail.com (Postfix) with ESMTP id 7F0C540100 for ; Mon, 13 Jun 2022 14:11:56 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R851e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046060;MF=xianting.tian@linux.alibaba.com;NM=1;PH=DS;RN=11;SR=0;TI=SMTPD_---0VGHIWD._1655125849; Received: from localhost(mailfrom:xianting.tian@linux.alibaba.com fp:SMTPD_---0VGHIWD._1655125849) by smtp.aliyun-inc.com; Mon, 13 Jun 2022 21:10:50 +0800 From: Xianting Tian To: akpm@linux-foundation.org, vbabka@suse.cz, ziy@nvidia.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, huanyi.xj@alibaba-inc.com, guoren@kernel.org, zjb194813@alibaba-inc.com, tianhu.hh@alibaba-inc.com, Xianting Tian Subject: [RESEND PATCH] mm: page_alloc: validate buddy before check the migratetype Date: Mon, 13 Jun 2022 21:10:46 +0800 Message-Id: <20220613131046.3009889-1-xianting.tian@linux.alibaba.com> X-Mailer: git-send-email 2.17.1 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655129519; a=rsa-sha256; cv=none; b=qb6/u37kbILbdnwWp7dgeslW365LdwrFbnqPdyWh93ixMKjtnAPycAYPUXw7pNEPPLhHqr f3NfkT7f0Qdi9cAYNA+QpxAxX2Fk6dzhXJcsb2EqRJiBA14ZZ0Z0XPpmGSRc3yszLLVpul YJv4MVprcDIm4gElUlRHL/pg3/eNR7A= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=alibaba.com; spf=pass (imf01.hostedemail.com: domain of xianting.tian@linux.alibaba.com designates 47.90.199.13 as permitted sender) smtp.mailfrom=xianting.tian@linux.alibaba.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655129519; 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=Z0xDkjOrV+CdYZsDe8y7C54SKZZutxLHJ7R0w63z1Gs=; b=5XC0WWb+ZisG9hwtkBP9hI8sarKiNQnM9K2JR91OObLdF2864TCowY2Bp2TH6E1lpc5G4X VthA0G88NEFKcrEHs2FHfG9PafdSR3DKy5MDqNzlCOboM00jE4BcdwPaOHTatazbVq9kXv rKNdSye0a2quf1tRjNABCYQ4dc/TgDU= Authentication-Results: imf01.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=alibaba.com; spf=pass (imf01.hostedemail.com: domain of xianting.tian@linux.alibaba.com designates 47.90.199.13 as permitted sender) smtp.mailfrom=xianting.tian@linux.alibaba.com X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 7F0C540100 X-Stat-Signature: xoihc9fptd84jyqhuh9frh9u8uq4bh3j X-Rspam-User: X-HE-Tag: 1655129516-193541 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.") added buddy check code. But unfortunately, this fix isn't backported to linux-5.17.y and the former stable branches. The reason is it added wrong fixes message: Fixes: 1dd214b8f21c ("mm: page_alloc: avoid merging non-fallbackable pageblocks with others") Actually, this issue is involved by commit: commit d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and other pageblocks") For RISC-V arch, the first 2M is reserved for sbi, so the start PFN is 512, but it got buddy PFN 0 for PFN 0x2000: 0 = 0x2000 ^ (1 << 12) With the illegal buddy PFN 0, it got an illegal buddy page, which caused crash in __get_pfnblock_flags_mask(). With the patch, it can avoid the calling of get_pageblock_migratetype() if it isn't buddy page. 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 b1caa1c6c887..5b423caa68fd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1129,6 +1129,9 @@ 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 -- 2.17.1