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=-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,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 10CC7C433E0 for ; Mon, 4 Jan 2021 07:05:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D70ED2087E for ; Mon, 4 Jan 2021 07:05:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727261AbhADHE5 (ORCPT ); Mon, 4 Jan 2021 02:04:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46770 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726962AbhADHE4 (ORCPT ); Mon, 4 Jan 2021 02:04:56 -0500 Received: from mail-pj1-x102c.google.com (mail-pj1-x102c.google.com [IPv6:2607:f8b0:4864:20::102c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E3F0C061793 for ; Sun, 3 Jan 2021 23:04:16 -0800 (PST) Received: by mail-pj1-x102c.google.com with SMTP id lb18so9458266pjb.5 for ; Sun, 03 Jan 2021 23:04:16 -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=cdofCMrJggOBDwndwOMcw9p8TURVKPl7TRF1bXWpuHc=; b=aO/iHhlqeDxAdcVAauKRuxsfxa53axv5jXOjkx2H1E3acuFc1j0hmtjQIyKCHBbHdq 3FIJJEqknwwg8BkrSycQgeqDvwp6qVqUX6uIiXxWA4lnz31JaswTjCfX/EHb4n4eH96T Sw15jb0AqfnZrj5Hp9nOj+CKl8N4nCFojlYELfu1OW9QbQt1PpsiJ0b01i2L4rOzIzWk eYc7nqGoxtraxVFZpSZk0pjL1mmbJ2Hk7ur555woz7092ZnKLnxi09UTfO3ODpu2BbUt QjLHKTWg9i/F5S6zxsbN4oiM4aQLFz9YrO2Kd90hDv8Ua4JCnpTcnUXVlA2UXZcUu1id kzTA== 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=cdofCMrJggOBDwndwOMcw9p8TURVKPl7TRF1bXWpuHc=; b=d4IULlSUqO0aLilnA07B5fjzWJ0mKHA/pnFY5qj+PgSReYkHYzVvfH0O8bJIHAf6+g Gz6u9NhcVdymgBtzg2KoRtHKwZFS0kUSI8p26lZBS0OsqsfvqiQAyYX03tcGX5Tt9O1Y Yj1olWM0MFMb4j0G/CWoR2f3g3xZw/t5644oRdl2d7KuSLUTVCGAfasaJIihg4VkCkD8 ZVyjwTC76lTXJ68DFKyeLgDmkYnsEnobVTWzQSsO5TzLS2hsCFG1gvG4tc3EUo2LvQEG c0yH7malvyh351hSuuLUoSeUJR1HsXjw/xCEUoFVG6UZhl0f9/M+JzdKT3HzaULa1Qz7 1P+Q== X-Gm-Message-State: AOAM530RT/9zxTa//r07f4gss4jyBCttr1AsXc8TwjULYjNBJoZL4XQP hpgAp7YhcPh7blz6VJjMxSxJ/w== X-Google-Smtp-Source: ABdhPJxzEpkaSXh/zCVLNlge5Wt3FV4tJQi4XZyc7KdMDbLQNQ845ylTEScxlIBO4YlKMLmldQpMYw== X-Received: by 2002:a17:90a:df81:: with SMTP id p1mr29396285pjv.158.1609743855735; Sun, 03 Jan 2021 23:04:15 -0800 (PST) Received: from localhost.localdomain ([240e:b1:e401:3::6]) by smtp.gmail.com with ESMTPSA id v1sm36306648pga.63.2021.01.03.23.03.54 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sun, 03 Jan 2021 23:04:15 -0800 (PST) From: Muchun Song To: mike.kravetz@oracle.com, akpm@linux-foundation.org Cc: hillf.zj@alibaba-inc.com, n-horiguchi@ah.jp.nec.com, ak@linux.intel.com, yongjun_wei@trendmicro.com.cn, mhocko@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Muchun Song Subject: [PATCH 5/6] mm: hugetlb: fix a race between isolating and freeing page Date: Mon, 4 Jan 2021 14:58:42 +0800 Message-Id: <20210104065843.5658-5-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) In-Reply-To: <20210104065843.5658-1-songmuchun@bytedance.com> References: <20210104065843.5658-1-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage") Signed-off-by: Muchun Song --- mm/hugetlb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index db00ae375d2a..5c2f64f53177 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5587,9 +5587,9 @@ bool isolate_huge_page(struct page *page, struct list_head *list) { 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; } -- 2.11.0