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=-15.7 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 5EF4EC433DB for ; Wed, 24 Feb 2021 20:08:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 11A1C64EC3 for ; Wed, 24 Feb 2021 20:08:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235158AbhBXUIm (ORCPT ); Wed, 24 Feb 2021 15:08:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:59764 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235372AbhBXUIG (ORCPT ); Wed, 24 Feb 2021 15:08:06 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9964764E60; Wed, 24 Feb 2021 20:07:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1614197271; bh=/PowuA+liQXKosAi5ro+HSU9tErdU/1suZR4xdRManE=; h=Date:From:To:Subject:In-Reply-To:From; b=jvOjdcmzKa5aBOYZ+fyNyBW2hJVjNkQRdaXh/D8Ntd5ODyhnrYVOoJZCPIgYkJoDf FRxeEIVvTk/8EqZvTBtX1BG7fxOuBTsl2KR9+Q9jHRU8oWrLD3xK5z17aBkWM3CFt6 trWjNffznm0i3evCunxpUI93ScH6chRbhfWhMKjo= Date: Wed, 24 Feb 2021 12:07:50 -0800 From: Andrew Morton To: aarcange@redhat.com, akpm@linux-foundation.org, dbueso@suse.de, joao.m.martins@oracle.com, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, osalvador@suse.de, stable@vger.kernel.org, torvalds@linux-foundation.org, willy@infradead.org, ziy@nvidia.com Subject: [patch 130/173] hugetlb: fix update_and_free_page contig page struct assumption Message-ID: <20210224200750.Dfh-Co_Ux%akpm@linux-foundation.org> In-Reply-To: <20210224115824.1e289a6895087f10c41dd8d6@linux-foundation.org> User-Agent: s-nail v14.8.16 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org =46rom: Mike Kravetz Subject: hugetlb: fix update_and_free_page contig page struct assumption page structs are not guaranteed to be contiguous for gigantic pages. The routine update_and_free_page can encounter a gigantic page, yet it assumes page structs are contiguous when setting page flags in subpages. If update_and_free_page encounters non-contiguous page structs, we can see =E2=80=9CBUG: Bad page state in process =E2=80=A6=E2=80=9D errors. Non-contiguous page structs are generally not an issue. However, they can exist with a specific kernel configuration and hotplug operations. For example: Configure the kernel with CONFIG_SPARSEMEM and !CONFIG_SPARSEMEM_VMEMMAP. Then, hotplug add memory for the area where the gigantic page will be allocated. Zi Yan outlined steps to reproduce here [1]. [1] https://lore.kernel.org/linux-mm/16F7C58B-4D79-41C5-9B64-A1A1628F4AF2@n= vidia.com/ Link: https://lkml.kernel.org/r/20210217184926.33567-1-mike.kravetz@oracle.= com Fixes: 944d9fec8d7a ("hugetlb: add support for gigantic page allocation at = runtime") Signed-off-by: Zi Yan Signed-off-by: Mike Kravetz Cc: Zi Yan Cc: Davidlohr Bueso Cc: "Kirill A . Shutemov" Cc: Andrea Arcangeli Cc: Matthew Wilcox Cc: Oscar Salvador Cc: Joao Martins Cc: Signed-off-by: Andrew Morton --- mm/hugetlb.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/mm/hugetlb.c~hugetlb-fix-update_and_free_page-contig-page-struct-assu= mption +++ a/mm/hugetlb.c @@ -1321,14 +1321,16 @@ static inline void destroy_compound_giga static void update_and_free_page(struct hstate *h, struct page *page) { int i; + struct page *subpage =3D page; =20 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) return; =20 h->nr_huge_pages--; h->nr_huge_pages_node[page_to_nid(page)]--; - for (i =3D 0; i < pages_per_huge_page(h); i++) { - page[i].flags &=3D ~(1 << PG_locked | 1 << PG_error | + for (i =3D 0; i < pages_per_huge_page(h); + i++, subpage =3D mem_map_next(subpage, page, i)) { + subpage->flags &=3D ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | 1 << PG_dirty | 1 << PG_active | 1 << PG_private | 1 << PG_writeback); _