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=-19.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 DB6DBC433DB for ; Mon, 8 Feb 2021 15:24:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 831F764DDB for ; Mon, 8 Feb 2021 15:24:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230216AbhBHPYF (ORCPT ); Mon, 8 Feb 2021 10:24:05 -0500 Received: from mail.kernel.org ([198.145.29.99]:60182 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233086AbhBHPRa (ORCPT ); Mon, 8 Feb 2021 10:17:30 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 22C5464EDC; Mon, 8 Feb 2021 15:11:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1612797120; bh=X5PD4eXLs9pxSyn0fEWADpvXyhUk0i2VaAEqHndORnk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qTm73FPGedk5TdgsihSTgqPWUHAWB35TpJivxXJGdxjjwhi0nNdImM+RiZd+VKjfc Xe06yWckjA2fFkwHDTnNNxkPR7DSahCMW5/I12UL+7JJ46pSXyHZZHG1xWKBLsKVyJ J7Gkj/EYJTTSoxrqezxScr7/XkKZg9QycLfZv3EY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Muchun Song , Mike Kravetz , Michal Hocko , Oscar Salvador , David Hildenbrand , Yang Shi , Andrew Morton , Linus Torvalds Subject: [PATCH 5.4 50/65] mm: hugetlb: fix a race between isolating and freeing page Date: Mon, 8 Feb 2021 16:01:22 +0100 Message-Id: <20210208145812.156983398@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210208145810.230485165@linuxfoundation.org> References: <20210208145810.230485165@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Muchun Song commit 0eb2df2b5629794020f75e94655e1994af63f0d4 upstream. There is a race between isolate_huge_page() and __free_huge_page(). CPU0: CPU1: if (PageHuge(page)) put_page(page) __free_huge_page(page) spin_lock(&hugetlb_lock) update_and_free_page(page) set_compound_page_dtor(page, NULL_COMPOUND_DTOR) spin_unlock(&hugetlb_lock) isolate_huge_page(page) // trigger BUG_ON VM_BUG_ON_PAGE(!PageHead(page), page) spin_lock(&hugetlb_lock) page_huge_active(page) // trigger BUG_ON VM_BUG_ON_PAGE(!PageHuge(page), page) spin_unlock(&hugetlb_lock) When we isolate a HugeTLB page on CPU0. Meanwhile, we free it to the buddy allocator on CPU1. Then, we can trigger a BUG_ON on CPU0, because it is already freed to the buddy allocator. Link: https://lkml.kernel.org/r/20210115124942.46403-5-songmuchun@bytedance.com Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage") Signed-off-by: Muchun Song Reviewed-by: Mike Kravetz Acked-by: Michal Hocko Reviewed-by: Oscar Salvador Cc: David Hildenbrand Cc: Yang Shi Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/hugetlb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5175,9 +5175,9 @@ bool isolate_huge_page(struct page *page { bool ret = true; - VM_BUG_ON_PAGE(!PageHead(page), page); spin_lock(&hugetlb_lock); - if (!page_huge_active(page) || !get_page_unless_zero(page)) { + if (!PageHeadHuge(page) || !page_huge_active(page) || + !get_page_unless_zero(page)) { ret = false; goto unlock; }