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 EC382C433F5 for ; Fri, 4 Mar 2022 09:36:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239062AbiCDJhM (ORCPT ); Fri, 4 Mar 2022 04:37:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237540AbiCDJgC (ORCPT ); Fri, 4 Mar 2022 04:36:02 -0500 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7627D18E3EA for ; Fri, 4 Mar 2022 01:35:10 -0800 (PST) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.53]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4K92fr5clbz9sRb; Fri, 4 Mar 2022 17:31:32 +0800 (CST) Received: from huawei.com (10.175.124.27) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Fri, 4 Mar 2022 17:35:07 +0800 From: Miaohe Lin To: CC: , , , , , , , , , , , , , , , , , , Subject: [PATCH 12/16] mm/migration: fix potential page refcounts leak in migrate_pages Date: Fri, 4 Mar 2022 17:34:05 +0800 Message-ID: <20220304093409.25829-13-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20220304093409.25829-1-linmiaohe@huawei.com> References: <20220304093409.25829-1-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In -ENOMEM case, there might be some subpages of fail-to-migrate THPs left in thp_split_pages list. We should move them back to migration list so that they could be put back to the right list by the caller otherwise the page refcnt will be leaked here. Also adjust nr_failed and nr_thp_failed accordingly to make vm events account more accurate. Fixes: b5bade978e9b ("mm: migrate: fix the return value of migrate_pages()") Signed-off-by: Miaohe Lin --- mm/migrate.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/mm/migrate.c b/mm/migrate.c index e0db06927f02..6c2dfed2ddb8 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1422,6 +1422,15 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, } nr_failed_pages += nr_subpages; + /* + * There might be some subpages of fail-to-migrate THPs + * left in thp_split_pages list. Move them back to migration + * list so that they could be put back to the right list by + * the caller otherwise the page refcnt will be leaked. + */ + list_splice_init(&thp_split_pages, from); + nr_failed += retry; + nr_thp_failed += thp_retry; goto out; case -EAGAIN: if (is_thp) -- 2.23.0