From patchwork Sun Jan 10 12:40:14 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Muchun Song X-Patchwork-Id: 360416 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=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, 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 95FD0C433E9 for ; Sun, 10 Jan 2021 12:42:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 608B222ADF for ; Sun, 10 Jan 2021 12:42:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726554AbhAJMmS (ORCPT ); Sun, 10 Jan 2021 07:42:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46550 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726069AbhAJMmQ (ORCPT ); Sun, 10 Jan 2021 07:42:16 -0500 Received: from mail-pl1-x62d.google.com (mail-pl1-x62d.google.com [IPv6:2607:f8b0:4864:20::62d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5AF78C0617A4 for ; Sun, 10 Jan 2021 04:41:36 -0800 (PST) Received: by mail-pl1-x62d.google.com with SMTP id e2so8038606plt.12 for ; Sun, 10 Jan 2021 04:41:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=I3gDuLjEjqpY5hJrgoP0zbm1oa1HSY0dQY30oFlgAYQ=; b=rWeFaHhdx26QIcu4oFq9jt4fdoiwTTEMHiX0GcDFnvXCNSEGXKNUOhSowItykhSP+s MU2lB7VGPKOpR26dagIJbSrZ0z4DQUseP8TI1Hr8218icPt2CE59nrthBPoGc5+2L0py GldzLHOZ/qQ22eoxfirNB/sX7sTFkGnYQS4NQwdHXLZ95tD8fo3K17CN+WvUYYuirXhr TpF+IMj8yyO/hRNwe/nRuTb4oq+CLbVTwC4ZMsGRxI8qPFxdbhi6TNcVuZv0oM+ZLqNg 4jK9h5RHhQ6APoWqIDlwAfx9/2k67z/4jNjM/HkPqSz2S5XOK+/rLaWpDAKaMrYgYVJT m2bg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=I3gDuLjEjqpY5hJrgoP0zbm1oa1HSY0dQY30oFlgAYQ=; b=DFiTh2E7nkdXmDmlDqLZj4X1S6ImZnn8PkF0I1LB8jp37T3OatLeI9G5j5LX99uvTm pkKfWgNY6N3QQEPK/oIlSmLMvyMqfa6GQ4YcYAPTyHoAlYeqxC1kr2aEXzhmcLYPI3Vc 2YZM6YlCB2QjPopq/lTCn/aBo2K3g+sfGTb8dGfMTpSybxRRqupiMGXpu2yecCmahy3A M/fXrx+6RvH6TvM/b0RhTD/NUGP/Ne93Q0PaFaD+Dqo2wumEyMrmeRel8jOW/1q1rDR0 R6V9w40E2Sk3gpuhqkC0KSYndFfhdlpkreFJ1n4w35yWfWEe1UOFHDrNJ1/JkRGo4R5q u8VQ== X-Gm-Message-State: AOAM5321f0s1FaVarncYnj4ndv+UPnMAxVFytycjKBfgiEXTBQtsiGGx KPpu+uwEztl1z9fINUE8GyHpMA== X-Google-Smtp-Source: ABdhPJzWrZDYsSoIxdfRxNA612sIivazrBh4X8Socv1b7/yltfVgFXyC4/ghwU7KuryYYJvTKH3CpQ== X-Received: by 2002:a17:90a:4402:: with SMTP id s2mr12942473pjg.37.1610282495977; Sun, 10 Jan 2021 04:41:35 -0800 (PST) Received: from localhost.localdomain ([139.177.225.247]) by smtp.gmail.com with ESMTPSA id p9sm16176960pfq.136.2021.01.10.04.41.32 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sun, 10 Jan 2021 04:41:35 -0800 (PST) From: Muchun Song To: mike.kravetz@oracle.com, akpm@linux-foundation.org Cc: n-horiguchi@ah.jp.nec.com, ak@linux.intel.com, mhocko@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Muchun Song , stable@vger.kernel.org Subject: [PATCH v3 3/6] mm: hugetlb: fix a race between freeing and dissolving the page Date: Sun, 10 Jan 2021 20:40:14 +0800 Message-Id: <20210110124017.86750-4-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) In-Reply-To: <20210110124017.86750-1-songmuchun@bytedance.com> References: <20210110124017.86750-1-songmuchun@bytedance.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org There is a race condition between __free_huge_page() and dissolve_free_huge_page(). CPU0: CPU1: // page_count(page) == 1 put_page(page) __free_huge_page(page) dissolve_free_huge_page(page) spin_lock(&hugetlb_lock) // PageHuge(page) && !page_count(page) update_and_free_page(page) // page is freed to the buddy spin_unlock(&hugetlb_lock) spin_lock(&hugetlb_lock) clear_page_huge_active(page) enqueue_huge_page(page) // It is wrong, the page is already freed spin_unlock(&hugetlb_lock) The race windows is between put_page() and dissolve_free_huge_page(). We should make sure that the page is already on the free list when it is dissolved. Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage") Signed-off-by: Muchun Song Cc: stable@vger.kernel.org Reviewed-by: Mike Kravetz --- mm/hugetlb.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 4741d60f8955..4a9011e12175 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -79,6 +79,21 @@ DEFINE_SPINLOCK(hugetlb_lock); static int num_fault_mutexes; struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp; +static inline bool PageHugeFreed(struct page *head) +{ + return page_private(head + 4) == -1UL; +} + +static inline void SetPageHugeFreed(struct page *head) +{ + set_page_private(head + 4, -1UL); +} + +static inline void ClearPageHugeFreed(struct page *head) +{ + set_page_private(head + 4, 0); +} + /* Forward declaration */ static int hugetlb_acct_memory(struct hstate *h, long delta); @@ -1028,6 +1043,7 @@ static void enqueue_huge_page(struct hstate *h, struct page *page) list_move(&page->lru, &h->hugepage_freelists[nid]); h->free_huge_pages++; h->free_huge_pages_node[nid]++; + SetPageHugeFreed(page); } static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid) @@ -1044,6 +1060,7 @@ static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid) list_move(&page->lru, &h->hugepage_activelist); set_page_refcounted(page); + ClearPageHugeFreed(page); h->free_huge_pages--; h->free_huge_pages_node[nid]--; return page; @@ -1504,6 +1521,7 @@ static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) spin_lock(&hugetlb_lock); h->nr_huge_pages++; h->nr_huge_pages_node[nid]++; + ClearPageHugeFreed(page); spin_unlock(&hugetlb_lock); } @@ -1770,6 +1788,14 @@ int dissolve_free_huge_page(struct page *page) int nid = page_to_nid(head); if (h->free_huge_pages - h->resv_huge_pages == 0) goto out; + + /* + * We should make sure that the page is already on the free list + * when it is dissolved. + */ + if (unlikely(!PageHugeFreed(head))) + goto out; + /* * Move PageHWPoison flag from head page to the raw error page, * which makes any subpages rather than the error page reusable.