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=unavailable 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 BF1C1C4332F for ; Tue, 21 Sep 2021 14:05:43 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 609AB611C5 for ; Tue, 21 Sep 2021 14:05:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 609AB611C5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id BCB64940007; Tue, 21 Sep 2021 10:05:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B7B056B0071; Tue, 21 Sep 2021 10:05:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A41A0940007; Tue, 21 Sep 2021 10:05:42 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0023.hostedemail.com [216.40.44.23]) by kanga.kvack.org (Postfix) with ESMTP id 9689A6B006C for ; Tue, 21 Sep 2021 10:05:42 -0400 (EDT) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 54ED52C586 for ; Tue, 21 Sep 2021 14:05:42 +0000 (UTC) X-FDA: 78611753724.03.86F6251 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf21.hostedemail.com (Postfix) with ESMTP id 60B6CD166CE2 for ; Tue, 21 Sep 2021 14:05:41 +0000 (UTC) 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 Authentication-Results: imf21.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=huawei.com; spf=pass (imf21.hostedemail.com: domain of chenjun102@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=chenjun102@huawei.com X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 60B6CD166CE2 X-Stat-Signature: kaoi87zbgb8o5wphqfp5utg5hmnegaeq X-HE-Tag: 1632233141-519572 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: 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