From patchwork Thu Feb 25 19:17:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 387622 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=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 65BC8C43381 for ; Thu, 25 Feb 2021 19:32:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 201A864F2A for ; Thu, 25 Feb 2021 19:32:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234761AbhBYTcX (ORCPT ); Thu, 25 Feb 2021 14:32:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:36924 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234879AbhBYTaP (ORCPT ); Thu, 25 Feb 2021 14:30:15 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id D392664F34; Thu, 25 Feb 2021 19:17:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1614280645; bh=moz1E1ye/uyWdvK7moV1jIZ9dVb5lZ9+JoUbnL+PstM=; h=Date:From:To:Subject:From; b=Tjz2nk/mCC8ArS0vbd0j/NnWNvCHOpImWODt8h9wQY443AdV9hKG3+PAWsGfM3LEo kofNu40gUETDzb6d0tgcpp9mTSxpK6cEn3TMLHdkdkekkjUWCVBhz4Qg6TVh3GZdsR zzqESnXBRVRHb/4MPTRaeynXm2YZgT8wF1aFoyZg= Date: Thu, 25 Feb 2021 11:17:24 -0800 From: akpm@linux-foundation.org To: aarcange@redhat.com, dbueso@suse.de, joao.m.martins@oracle.com, kirill.shutemov@linux.intel.com, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, osalvador@suse.de, stable@vger.kernel.org, willy@infradead.org, ziy@nvidia.com Subject: [merged] hugetlb-fix-update_and_free_page-contig-page-struct-assumption.patch removed from -mm tree Message-ID: <20210225191724.8ziH2aj_k%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: hugetlb: fix update_and_free_page contig page struct assumption has been removed from the -mm tree. Its filename was hugetlb-fix-update_and_free_page-contig-page-struct-assumption.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: 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 “BUG: Bad page state in process …” 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@nvidia.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-assumption +++ 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 = page; if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) return; h->nr_huge_pages--; h->nr_huge_pages_node[page_to_nid(page)]--; - for (i = 0; i < pages_per_huge_page(h); i++) { - page[i].flags &= ~(1 << PG_locked | 1 << PG_error | + for (i = 0; i < pages_per_huge_page(h); + i++, subpage = mem_map_next(subpage, page, i)) { + subpage->flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | 1 << PG_dirty | 1 << PG_active | 1 << PG_private | 1 << PG_writeback);