From nobody Tue Jun 23 01:16:27 2026 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 441FAC433F5 for ; Mon, 14 Mar 2022 06:41:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236449AbiCNGmn (ORCPT ); Mon, 14 Mar 2022 02:42:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38042 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229724AbiCNGmm (ORCPT ); Mon, 14 Mar 2022 02:42:42 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 736C53D1F8 for ; Sun, 13 Mar 2022 23:41:33 -0700 (PDT) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4KH6NP2qptzfZ2s; Mon, 14 Mar 2022 14:40:05 +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; Mon, 14 Mar 2022 14:41:31 +0800 From: Miaohe Lin To: , CC: , , Subject: [PATCH v2] mm/mlock: fix potential imbalanced rlimit ucounts adjustment Date: Mon, 14 Mar 2022 14:40:39 +0800 Message-ID: <20220314064039.62972-1-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) 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 Content-Type: text/plain; charset="utf-8" user_shm_lock forgets to set allowed to 0 when get_ucounts fails. So the later user_shm_unlock might do the extra dec_rlimit_ucounts. Fix this by resetting allowed to 0. Fixes: d7c9e99aee48 ("Reimplement RLIMIT_MEMLOCK on top of ucounts") Signed-off-by: Miaohe Lin Acked-by: Hugh Dickins --- v1->v2: correct Fixes tag and collect Acked-by tag Thanks Hugh for review! --- mm/mlock.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/mlock.c b/mm/mlock.c index 29372c0eebe5..efd2dd2943de 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -733,6 +733,7 @@ int user_shm_lock(size_t size, struct ucounts *ucounts) } if (!get_ucounts(ucounts)) { dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); + allowed =3D 0; goto out; } allowed =3D 1; --=20 2.23.0