From patchwork Fri Mar 4 09:34:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miaohe Lin X-Patchwork-Id: 12768816 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 46110C433F5 for ; Fri, 4 Mar 2022 09:35:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5EA038D000F; Fri, 4 Mar 2022 04:35:12 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 54A098D0005; Fri, 4 Mar 2022 04:35:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4397F8D000F; Fri, 4 Mar 2022 04:35:12 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.27]) by kanga.kvack.org (Postfix) with ESMTP id 30DB08D0005 for ; Fri, 4 Mar 2022 04:35:12 -0500 (EST) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id F3D1D24A6F for ; Fri, 4 Mar 2022 09:35:11 +0000 (UTC) X-FDA: 79206195264.09.0823733 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by imf19.hostedemail.com (Postfix) with ESMTP id 39C561A000F for ; Fri, 4 Mar 2022 09:35:11 +0000 (UTC) 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 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 X-Rspamd-Queue-Id: 39C561A000F X-Stat-Signature: cnqckc69fk7qpab7snee7yp58x5j1iwn X-Rspam-User: Authentication-Results: imf19.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf19.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.189 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com X-Rspamd-Server: rspam03 X-HE-Tag: 1646386511-112847 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 Reviewed-by: "Huang, Ying" Reviewed-by: Baolin Wang --- 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)