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=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 C36AEC433E0 for ; Fri, 15 Jan 2021 13:27:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5F36E23382 for ; Fri, 15 Jan 2021 13:27:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5F36E23382 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id EF9A98D0175; Fri, 15 Jan 2021 08:27:02 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EAADE8D0162; Fri, 15 Jan 2021 08:27:02 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DE7298D0175; Fri, 15 Jan 2021 08:27:02 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0083.hostedemail.com [216.40.44.83]) by kanga.kvack.org (Postfix) with ESMTP id C88998D0162 for ; Fri, 15 Jan 2021 08:27:02 -0500 (EST) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 8F78D181AF5C3 for ; Fri, 15 Jan 2021 13:27:02 +0000 (UTC) X-FDA: 77708085084.05.waves77_06130012752f Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin05.hostedemail.com (Postfix) with ESMTP id 71BCC1803816D for ; Fri, 15 Jan 2021 13:27:02 +0000 (UTC) X-HE-Tag: waves77_06130012752f X-Filterd-Recvd-Size: 2754 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf24.hostedemail.com (Postfix) with ESMTP for ; Fri, 15 Jan 2021 13:27:01 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id BE98FAC8F; Fri, 15 Jan 2021 13:27:00 +0000 (UTC) Date: Fri, 15 Jan 2021 14:26:58 +0100 From: Oscar Salvador To: Muchun Song Cc: mike.kravetz@oracle.com, akpm@linux-foundation.org, n-horiguchi@ah.jp.nec.com, ak@linux.intel.com, mhocko@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Michal Hocko , stable@vger.kernel.org Subject: Re: [PATCH v6 4/5] mm: hugetlb: fix a race between isolating and freeing page Message-ID: <20210115132658.GB10102@linux> References: <20210115124942.46403-1-songmuchun@bytedance.com> <20210115124942.46403-5-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210115124942.46403-5-songmuchun@bytedance.com> User-Agent: Mutt/1.10.1 (2018-07-13) 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: On Fri, Jan 15, 2021 at 08:49:41PM +0800, Muchun Song wrote: > 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 Reviewed-by: Oscar Salvador -- Oscar Salvador SUSE L3