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=-16.7 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 37505C433EF for ; Tue, 21 Sep 2021 14:05:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18D0C61184 for ; Tue, 21 Sep 2021 14:05:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233491AbhIUOHJ (ORCPT ); Tue, 21 Sep 2021 10:07:09 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:9896 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233042AbhIUOHG (ORCPT ); Tue, 21 Sep 2021 10:07:06 -0400 Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4HDNPW3wytz8y0F; Tue, 21 Sep 2021 22:01:03 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Tue, 21 Sep 2021 22:05:35 +0800 Received: from mdc.huawei.com (10.175.112.208) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Tue, 21 Sep 2021 22:05:34 +0800 From: Chen Jun To: , CC: , , , Subject: [PATCH] mm: Fix the uninitialized use in overcommit_policy_handler Date: Tue, 21 Sep 2021 14:03:01 +0000 Message-ID: <20210921140301.9058-1-chenjun102@huawei.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.175.112.208] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org An unexpected value of /proc/sys/vm/panic_on_oom we will get, after running the following program int main() { int fd = open("/proc/sys/vm/panic_on_oom", O_RDWR) write(fd, "1", 1); write(fd, "2", 1); close(fd); } write(fd, "2", 1) will pass *ppos = 1 to proc_dointvec_minmax. proc_dointvec_minmax will return 0 without setting new_policy. t.data = &new_policy; ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos) -->do_proc_dointvec -->__do_proc_dointvec if (write) { if (proc_first_pos_non_zero_ignore(ppos, table)) goto out; sysctl_overcommit_memory = new_policy; so sysctl_overcommit_memory will be set to an uninitialized value. Initialize new_policy with sysctl_overcommit_memory. Fixes: 56f3547bfa4d ("mm: adjust vm_committed_as_batch according to vm overcommit policy" Signed-off-by: Chen Jun --- mm/util.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/util.c b/mm/util.c index 4ddb6e186dd5..b4af8a1de4f7 100644 --- a/mm/util.c +++ b/mm/util.c @@ -756,7 +756,7 @@ int overcommit_policy_handler(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { struct ctl_table t; - int new_policy; + int new_policy = sysctl_overcommit_memory; int ret; /* -- 2.17.1