From patchwork Mon Feb 8 17:20:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 379106 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=-15.8 required=3.0 tests=BAYES_00,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 autolearn=unavailable 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 76DD6C433E9 for ; Mon, 8 Feb 2021 17:24:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2AED764E45 for ; Mon, 8 Feb 2021 17:24:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231720AbhBHRXw (ORCPT ); Mon, 8 Feb 2021 12:23:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:34780 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232286AbhBHRWt (ORCPT ); Mon, 8 Feb 2021 12:22:49 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id C111064E8F; Mon, 8 Feb 2021 17:20:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1612804840; bh=gfzwbbSpJCj9w0shoqiaVqZL0JZYWxRRzObu6/o9I5Y=; h=Date:From:To:Subject:From; b=T635pDhsUiNYvAUJkOVM7dUHV4XPTKziH/L43nLFOJxNRCQ++X64MsSx/7HH7Aorf gmOTOBHU1f8JfmkURUlVH25f+LfCFtbWUn9bXXq6CFlt3g0oVSte5uic8vBObD8YT9 /EyIahq7bEwlJez9qnywa65K9OzqlIAm7HVo2+U8= Date: Mon, 08 Feb 2021 09:20:39 -0800 From: akpm@linux-foundation.org To: david@redhat.com, mhocko@suse.com, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, osalvador@suse.de, shy828301@gmail.com, songmuchun@bytedance.com, stable@vger.kernel.org Subject: [merged] mm-hugetlb-fix-a-race-between-isolating-and-freeing-page.patch removed from -mm tree Message-ID: <20210208172039.Sm82d1MQd%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: mm: hugetlb: fix a race between isolating and freeing page has been removed from the -mm tree. Its filename was mm-hugetlb-fix-a-race-between-isolating-and-freeing-page.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Muchun Song Subject: mm: hugetlb: fix a race between isolating and freeing page 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 --- mm/hugetlb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/mm/hugetlb.c~mm-hugetlb-fix-a-race-between-isolating-and-freeing-page +++ a/mm/hugetlb.c @@ -5594,9 +5594,9 @@ 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; }