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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D390FC4332F for ; Mon, 28 Mar 2022 22:15:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229809AbiC1WRf (ORCPT ); Mon, 28 Mar 2022 18:17:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40312 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229966AbiC1WQl (ORCPT ); Mon, 28 Mar 2022 18:16:41 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 404F21385A8 for ; Mon, 28 Mar 2022 15:13:08 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D44FF61477 for ; Mon, 28 Mar 2022 22:13:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3A63FC340F0; Mon, 28 Mar 2022 22:13:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1648505587; bh=XyHl3obvLAt/Xu4p8yJiyjaJh6wKfaC94RQfz+o3ytM=; h=Date:To:From:Subject:From; b=m4fL3emNyOKnk0k434pD7qv8nVM8WtOKrTf1jqv9SaPLjIYEtRFGCnxV8HlZoOfED pK8hGT2g3qN4yuPQqHMYO6nl753FXXnWm6VsIBpK3iLkvjGIRk4NORDADmFSximGe4 pIft+gGjEg0LJSTWT2fgSDCKHtLMufwfy3fY/oC8= Date: Mon, 28 Mar 2022 15:13:06 -0700 To: mm-commits@vger.kernel.org, ziy@nvidia.com, ying.huang@intel.com, songmuchun@bytedance.com, baolin.wang@linux.alibaba.com, apopple@nvidia.com, linmiaohe@huawei.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-migration-fix-possible-do_pages_stat_array-racing-with-memory-offline.patch added to -mm tree Message-Id: <20220328221307.3A63FC340F0@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/migration: fix possible do_pages_stat_array racing with memory offline has been added to the -mm tree. Its filename is mm-migration-fix-possible-do_pages_stat_array-racing-with-memory-offline.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-migration-fix-possible-do_pages_stat_array-racing-with-memory-offline.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-migration-fix-possible-do_pages_stat_array-racing-with-memory-offline.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: Miaohe Lin Subject: mm/migration: fix possible do_pages_stat_array racing with memory offline When follow_page peeks a page, the page could be migrated and then be offlined while it's still being used by the do_pages_stat_array(). Use FOLL_GET to hold the page refcnt to fix this potential race. Link: https://lkml.kernel.org/r/20220318111709.60311-12-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Acked-by: "Huang, Ying" Reviewed-by: Muchun Song Cc: Alistair Popple Cc: Baolin Wang Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/migrate.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/mm/migrate.c~mm-migration-fix-possible-do_pages_stat_array-racing-with-memory-offline +++ a/mm/migrate.c @@ -1798,13 +1798,18 @@ static void do_pages_stat_array(struct m goto set_status; /* FOLL_DUMP to ignore special (like zero) pages */ - page = follow_page(vma, addr, FOLL_DUMP); + page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); err = PTR_ERR(page); if (IS_ERR(page)) goto set_status; - err = page ? page_to_nid(page) : -ENOENT; + if (page) { + err = page_to_nid(page); + put_page(page); + } else { + err = -ENOENT; + } set_status: *status = err; _ Patches currently in -mm which might be from linmiaohe@huawei.com are mm-shmem-make-shmem_init-return-void.patch mm-memcg-remove-unneeded-nr_scanned.patch mm-mremap-use-helper-mlock_future_check.patch mm-mlock-fix-two-bugs-in-user_shm_lock.patch mm-compaction-use-helper-isolation_suitable.patch mm-migration-remove-unneeded-local-variable-mapping_locked.patch mm-migration-remove-unneeded-out-label.patch mm-migration-remove-unneeded-local-variable-page_lru.patch mm-migration-fix-the-confusing-pagetranshuge-check.patch mm-migration-use-helper-function-vma_lookup-in-add_page_for_migration.patch mm-migration-use-helper-macro-min-in-do_pages_stat.patch mm-migration-avoid-unneeded-nodemask_t-initialization.patch mm-migration-remove-some-duplicated-codes-in-migrate_pages.patch mm-migration-fix-potential-page-refcounts-leak-in-migrate_pages.patch mm-migration-fix-potential-invalid-node-access-for-reclaim-based-migration.patch mm-migration-fix-possible-do_pages_stat_array-racing-with-memory-offline.patch