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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 AB217C41537 for ; Sat, 7 Aug 2021 09:36:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9DF8561164 for ; Sat, 7 Aug 2021 09:36:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231732AbhHGJgm (ORCPT ); Sat, 7 Aug 2021 05:36:42 -0400 Received: from szxga08-in.huawei.com ([45.249.212.255]:13247 "EHLO szxga08-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231681AbhHGJgh (ORCPT ); Sat, 7 Aug 2021 05:36:37 -0400 Received: from dggeme703-chm.china.huawei.com (unknown [172.30.72.55]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4Ghcfd6sNTz1CT3G; Sat, 7 Aug 2021 17:36:09 +0800 (CST) Received: from huawei.com (10.175.124.27) by dggeme703-chm.china.huawei.com (10.1.199.99) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Sat, 7 Aug 2021 17:36:19 +0800 From: Miaohe Lin To: CC: , , , , , , Subject: [PATCH 4/5] mm: gup: fix potential pgmap refcnt leak in __gup_device_huge() Date: Sat, 7 Aug 2021 17:36:19 +0800 Message-ID: <20210807093620.21347-5-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20210807093620.21347-1-linmiaohe@huawei.com> References: <20210807093620.21347-1-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: dggems706-chm.china.huawei.com (10.3.19.183) To dggeme703-chm.china.huawei.com (10.1.199.99) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When failed to try_grab_page, put_dev_pagemap() is missed. So pgmap refcnt will leak in this case. Also we remove the check for pgmap against NULL as it's also checked inside the put_dev_pagemap(). Signed-off-by: Miaohe Lin Fixes: 3faa52c03f44 ("mm/gup: track FOLL_PIN pages") --- mm/gup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index d7e4507de6b1..8c89e614d4aa 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2253,14 +2253,14 @@ static int __gup_device_huge(unsigned long pfn, unsigned long addr, pages[*nr] = page; if (unlikely(!try_grab_page(page, flags))) { undo_dev_pagemap(nr, nr_start, flags, pages); + put_dev_pagemap(pgmap); return 0; } (*nr)++; pfn++; } while (addr += PAGE_SIZE, addr != end); - if (pgmap) - put_dev_pagemap(pgmap); + put_dev_pagemap(pgmap); return 1; } -- 2.23.0