From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751500AbeAVKiI (ORCPT ); Mon, 22 Jan 2018 05:38:08 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:55706 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751052AbeAVKiF (ORCPT ); Mon, 22 Jan 2018 05:38:05 -0500 Date: Mon, 22 Jan 2018 13:27:54 +0300 From: Dan Carpenter To: "Luis R. Rodriguez" Cc: linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH] lib/test_kmod: Fix an integer overflow test Message-ID: <20180122102754.GD23912@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mailer: git-send-email haha only kidding User-Agent: Mutt/1.9.2 (2017-12-15) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8781 signatures=668655 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=969 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1711220000 definitions=main-1801220153 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The main problem is that the parentheses are in the wrong place and the unlikely() call returns either 0 or 1 so it's never less than zero. The other problem is that signed integer overflows like "INT_MAX + 1" are undefined behavior. Fixes: d9c6a72d6fa2 ("kmod: add test driver to stress test the module loader") Signed-off-by: Dan Carpenter diff --git a/lib/test_kmod.c b/lib/test_kmod.c index e372b97eee13..30fd6d9e5361 100644 --- a/lib/test_kmod.c +++ b/lib/test_kmod.c @@ -1141,7 +1141,7 @@ static struct kmod_test_device *register_test_dev_kmod(void) mutex_lock(®_dev_mutex); /* int should suffice for number of devices, test for wrap */ - if (unlikely(num_test_devs + 1) < 0) { + if (num_test_devs == INT_MAX) { pr_err("reached limit of number of test devices\n"); goto out; }