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 2FA72C433DB for ; Wed, 13 Jan 2021 05:26:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E1D6322B37 for ; Wed, 13 Jan 2021 05:26:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726377AbhAMF0y (ORCPT ); Wed, 13 Jan 2021 00:26:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33322 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726308AbhAMF0w (ORCPT ); Wed, 13 Jan 2021 00:26:52 -0500 Received: from mail-pg1-x52e.google.com (mail-pg1-x52e.google.com [IPv6:2607:f8b0:4864:20::52e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 53AAFC061575 for ; Tue, 12 Jan 2021 21:25:53 -0800 (PST) Received: by mail-pg1-x52e.google.com with SMTP id 30so766560pgr.6 for ; Tue, 12 Jan 2021 21:25:53 -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=7IILliy6HAELOAf2o6Y4OfnqFvSJBzlwsRQjJedxot0=; b=dJSU9wJz/3rQWPdMgFSeLg9iISXgA+mrG+M6gt+bsIjssGtFTfPEsERPEUS/5t83/a LUUhWWNg/MtzqsN1Kcpq3X30J5yof6IfmScrbd2duBHq6YKTHipysgbq0GgU5xk6pS2e zjsxPKhbFQ3aQpWwXgTAKahmN+gYTipJrmzzMWPn1qre9ExAnmti5MKJc035HZOxbRYj iHy8ulllb0ZqY2Um8SLjP+3fu+8cZOBSSgRpFiASO+QylIjnslUNIoap6l6hYXze4wgD w4WSsWwgioG3c1Cy6a1OJW3JNITIUff9+LHkCpsmdjVxblAQrvZnTkHGQvdlc1TgFK6d 1KbA== 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=7IILliy6HAELOAf2o6Y4OfnqFvSJBzlwsRQjJedxot0=; b=uVfNmQUmID/1q1K8X+ZcQsR/+eZ/pr/cb+aR9Xk1KHom8swI1TVnkmkhFmtGgYqPSH kJpfko4Cij3FdvkMPsPrt+/52EsLNK7jy50he+h8roX2XdrgaigUiuR+BDNMQrVnE4cI ppy1CsYGwLq/fyeNfUyrQKyvbJhDi7v09VxO6Epd7wIeZXMUiBPeh4vM+J5RAjiLT1xv RElSYA1aOBoUoYfydMjqjKosb4N6vwi7CC3g2VcGoB+Ecv5SMPM3C4gnB+uPTCRJR+ZG UUyTOTesUT7hNVZa0pUrwUTw/UNOi/Rr+ot4Zhz5FwWkSEZVnwUuPKnpKCbaKh4ExNNr JB+A== X-Gm-Message-State: AOAM5311Cw/MRs/j1ClCrnRviymFMWmNWKe2bK7Pemsmb578Tj1lRuna TQIdTirgvFQzR/WPMWw+OQVOgg== X-Google-Smtp-Source: ABdhPJyzBXCuQ9SD6Bb7oZ1eb4Ev3kY+H2KEd84rW3RSKql2lLp9DD8eqP0VXQA4l2FJ/CVALwQ2ZQ== X-Received: by 2002:a63:1110:: with SMTP id g16mr459913pgl.357.1610515552956; Tue, 12 Jan 2021 21:25:52 -0800 (PST) Received: from localhost.localdomain ([139.177.225.247]) by smtp.gmail.com with ESMTPSA id x15sm893081pfa.80.2021.01.12.21.25.48 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 12 Jan 2021 21:25:52 -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 , Michal Hocko , stable@vger.kernel.org Subject: [PATCH v4 5/6] mm: hugetlb: fix a race between isolating and freeing page Date: Wed, 13 Jan 2021 13:22:08 +0800 Message-Id: <20210113052209.75531-6-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) In-Reply-To: <20210113052209.75531-1-songmuchun@bytedance.com> References: <20210113052209.75531-1-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 Reviewed-by: Mike Kravetz Acked-by: Michal Hocko Cc: stable@vger.kernel.org --- mm/hugetlb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 898e4ea43e13..a7ed22811672 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5575,9 +5575,9 @@ 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