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,URIBL_RED 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 EB7F0C433DB for ; Sun, 24 Jan 2021 05:02:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFADE22C9F for ; Sun, 24 Jan 2021 05:02:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726369AbhAXFCz (ORCPT ); Sun, 24 Jan 2021 00:02:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:47458 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726252AbhAXFCr (ORCPT ); Sun, 24 Jan 2021 00:02:47 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id BF1C322CAF; Sun, 24 Jan 2021 05:01:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1611464514; bh=pcz3PCqxYzxs5kJ6kwRGGOcJPEtj0FCO0fqNHgQmnac=; h=Date:From:To:Subject:In-Reply-To:From; b=wB3ctqADZRXjXwvFYSEMxjCWcjIlPnnBgID8LlbMEy6E6K84dIgHuqfg+PnVUCcoG /KW4J+zY68jzM7HrZrq78YOz5zAohY8RvhMko7xCegLjpXKu5M5rBI/s2mIkunHAgk qQBuBdlODqS29OzafpGTumdPRGJmlZfhZAYtdePU= Date: Sat, 23 Jan 2021 21:01:52 -0800 From: Andrew Morton To: akpm@linux-foundation.org, cai@lca.pw, dan.j.williams@intel.com, david@redhat.com, linux-mm@kvack.org, mhocko@suse.com, mm-commits@vger.kernel.org, naoya.horiguchi@nec.com, osalvador@suse.de, stable@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 13/19] mm: fix page reference leak in soft_offline_page() Message-ID: <20210124050152.mIDl3p6sw%akpm@linux-foundation.org> In-Reply-To: <20210123210029.a7c704d0cab204683e41ad10@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 From: Dan Williams Subject: mm: fix page reference leak in soft_offline_page() The conversion to move pfn_to_online_page() internal to soft_offline_page() missed that the get_user_pages() reference taken by the madvise() path needs to be dropped when pfn_to_online_page() fails. Note the direct sysfs-path to soft_offline_page() does not perform a get_user_pages() lookup. When soft_offline_page() is handed a pfn_valid() && !pfn_to_online_page() pfn the kernel hangs at dax-device shutdown due to a leaked reference. Link: https://lkml.kernel.org/r/161058501210.1840162.8108917599181157327.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: feec24a6139d ("mm, soft-offline: convert parameter to pfn") Signed-off-by: Dan Williams Reviewed-by: David Hildenbrand Reviewed-by: Oscar Salvador Reviewed-by: Naoya Horiguchi Cc: Michal Hocko Cc: Qian Cai Cc: Signed-off-by: Andrew Morton --- mm/memory-failure.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) --- a/mm/memory-failure.c~mm-fix-page-reference-leak-in-soft_offline_page +++ a/mm/memory-failure.c @@ -1885,6 +1885,12 @@ static int soft_offline_free_page(struct return rc; } +static void put_ref_page(struct page *page) +{ + if (page) + put_page(page); +} + /** * soft_offline_page - Soft offline a page. * @pfn: pfn to soft-offline @@ -1910,20 +1916,26 @@ static int soft_offline_free_page(struct int soft_offline_page(unsigned long pfn, int flags) { int ret; - struct page *page; bool try_again = true; + struct page *page, *ref_page = NULL; + + WARN_ON_ONCE(!pfn_valid(pfn) && (flags & MF_COUNT_INCREASED)); if (!pfn_valid(pfn)) return -ENXIO; + if (flags & MF_COUNT_INCREASED) + ref_page = pfn_to_page(pfn); + /* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */ page = pfn_to_online_page(pfn); - if (!page) + if (!page) { + put_ref_page(ref_page); return -EIO; + } if (PageHWPoison(page)) { pr_info("%s: %#lx page already poisoned\n", __func__, pfn); - if (flags & MF_COUNT_INCREASED) - put_page(page); + put_ref_page(ref_page); return 0; } _