From patchwork Wed Feb 17 19:06:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 384330 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=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 3DDCFC433E0 for ; Wed, 17 Feb 2021 19:07:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0BB3364DE0 for ; Wed, 17 Feb 2021 19:07:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229806AbhBQTHX (ORCPT ); Wed, 17 Feb 2021 14:07:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:51270 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231439AbhBQTHW (ORCPT ); Wed, 17 Feb 2021 14:07:22 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 09CE264DE0; Wed, 17 Feb 2021 19:06:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1613588801; bh=wmMbEgQUr3JrFli1SCzjAY5ndgEnQKnrID4cKCb1ZCg=; h=Date:From:To:Subject:From; b=Xq4Qr1oUzpvwjKziqaKk1b9EZQbv87pf+Z5oXBpSimwom29LnbgrrJ7D0PxYs788E BUgJV2foMkYxirldnr9A7dEC4BA8NQnW3qrHTToJ8Q2suyTbbup1WfnApJnhx7QZCv wwGUhQFiqHtIiUN3Q/jvRwHxRfyHl5blE0bnN7GE= Date: Wed, 17 Feb 2021 11:06:40 -0800 From: akpm@linux-foundation.org To: mm-commits@vger.kernel.org, ziy@nvidia.com, willy@infradead.org, stable@vger.kernel.org, osalvador@suse.de, kirill.shutemov@linux.intel.com, joao.m.martins@oracle.com, dbueso@suse.de, aarcange@redhat.com, mike.kravetz@oracle.com Subject: + hugetlb-fix-update_and_free_page-contig-page-struct-assumption.patch added to -mm tree Message-ID: <20210217190640.BiIUU%akpm@linux-foundation.org> User-Agent: s-nail v14.9.10 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 added to the -mm tree. Its filename is hugetlb-fix-update_and_free_page-contig-page-struct-assumption.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/hugetlb-fix-update_and_free_page-contig-page-struct-assumption.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/hugetlb-fix-update_and_free_page-contig-page-struct-assumption.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: 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);