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 C1BFCC433DB for ; Mon, 1 Feb 2021 07:53:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 629A364E08 for ; Mon, 1 Feb 2021 07:53:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232283AbhBAHxB (ORCPT ); Mon, 1 Feb 2021 02:53:01 -0500 Received: from szxga04-in.huawei.com ([45.249.212.190]:11663 "EHLO szxga04-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232281AbhBAHw6 (ORCPT ); Mon, 1 Feb 2021 02:52:58 -0500 Received: from DGGEMS409-HUB.china.huawei.com (unknown [172.30.72.58]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4DTg8333NxzlDl8; Mon, 1 Feb 2021 15:49:39 +0800 (CST) Received: from huawei.com (10.175.127.227) by DGGEMS409-HUB.china.huawei.com (10.3.19.209) with Microsoft SMTP Server id 14.3.498.0; Mon, 1 Feb 2021 15:51:06 +0800 From: Sun Ke To: CC: , Subject: [PATCH v2] src/swapon.c: initiate p to NULL Date: Mon, 1 Feb 2021 15:57:05 +0800 Message-ID: <20210201075705.779959-1-sunke32@huawei.com> X-Mailer: git-send-email 2.25.4 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.127.227] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: fstests@vger.kernel.org when run make, show: swapon.c:135:3: warning: 'p' may be used uninitialized in this function [-Wmaybe-uninitialized] memcpy(p, buf, BUF_SIZE); ^~~~~~~~~~~~~~~~~~~~~~~~ This's a fake uninitialized warning. gcc think the 'p' can be used uninitialized at here when verb is TEST_MWRITE_BEFORE_AND_MWRITE_AFTER: case TEST_MWRITE_BEFORE_AND_MWRITE_AFTER: memcpy(p, buf, BUF_SIZE); break; But, if verb is TEST_MWRITE_BEFORE_AND_MWRITE_AFTER, the 'p' will be initialized by: switch (verb) { case TEST_MWRITE_BEFORE_AND_MWRITE_AFTER: case TEST_MWRITE_BEFORE: p = mmap(NULL, BUF_SIZE, PROT_WRITE | PROT_READ, MAP_SHARED, Shall we make the build warning disappear? Signed-off-by: Sun Ke --- V2: Improve the commit message. --- src/swapon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/swapon.c b/src/swapon.c index afaed405..fe8949a3 100644 --- a/src/swapon.c +++ b/src/swapon.c @@ -41,7 +41,7 @@ int main(int argc, char **argv) .sa_handler = handle_signal, }; enum verbs verb = TEST_SWAPON; - void *p; + void *p = NULL; ssize_t sz; int fd = -1; int ret, c; -- 2.13.6