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=-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 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 582DDC4332B for ; Sun, 17 Jan 2021 20:56:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1E82B22227 for ; Sun, 17 Jan 2021 20:56:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729947AbhAQU4y (ORCPT ); Sun, 17 Jan 2021 15:56:54 -0500 Received: from mail.kernel.org ([198.145.29.99]:49862 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729880AbhAQU4q (ORCPT ); Sun, 17 Jan 2021 15:56:46 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id ADBD122227; Sun, 17 Jan 2021 20:56:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1610916965; bh=QMaNKU2Oo18lF5KfGXb+ReOscTmbRt63o4yJoNv2ax0=; h=Date:From:To:Subject:From; b=pyvIw9cqOV3eEA4U6Lxa4bkCOeyn3odhzLmor6GztRRz18TvhGwVPaLLNSaxVsTt1 hvHuSVfdVFC3/Yj0BSU0VEQHwKgS0/m0C3ENkMXvIT4ro+xR/emzwMM9FG47f5XY07 aGwt6xxV9RdAr1Cq+T/hKuQwadi5lxER8f0vz6R4= Date: Sun, 17 Jan 2021 12:56:02 -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: + mm-hugetlb-fix-a-race-between-isolating-and-freeing-page.patch added to -mm tree Message-ID: <20210117205602.KaF80PEKX%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm: hugetlb: fix a race between isolating and freeing page has been added to the -mm tree. Its filename is mm-hugetlb-fix-a-race-between-isolating-and-freeing-page.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-fix-a-race-between-isolating-and-freeing-page.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-fix-a-race-between-isolating-and-freeing-page.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ 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; } _ Patches currently in -mm which might be from songmuchun@bytedance.com are mm-hugetlbfs-fix-cannot-migrate-the-fallocated-hugetlb-page.patch mm-hugetlb-fix-a-race-between-freeing-and-dissolving-the-page.patch mm-hugetlb-fix-a-race-between-isolating-and-freeing-page.patch mm-hugetlb-remove-vm_bug_on_page-from-page_huge_active.patch mm-migrate-do-not-migrate-hugetlb-page-whose-refcount-is-one.patch mm-memcontrol-optimize-per-lruvec-stats-counter-memory-usage.patch mm-memcontrol-fix-nr_anon_thps-accounting-in-charge-moving.patch mm-memcontrol-convert-nr_anon_thps-account-to-pages.patch mm-memcontrol-convert-nr_file_thps-account-to-pages.patch mm-memcontrol-convert-nr_shmem_thps-account-to-pages.patch mm-memcontrol-convert-nr_shmem_pmdmapped-account-to-pages.patch mm-memcontrol-convert-nr_file_pmdmapped-account-to-pages.patch mm-memcontrol-make-the-slab-calculation-consistent.patch