From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752600Ab3FYBRZ (ORCPT ); Mon, 24 Jun 2013 21:17:25 -0400 Received: from intranet.asianux.com ([58.214.24.6]:49524 "EHLO intranet.asianux.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751414Ab3FYBRW (ORCPT ); Mon, 24 Jun 2013 21:17:22 -0400 X-Spam-Score: -100.7 Message-ID: <51C8EF6F.4050803@asianux.com> Date: Tue, 25 Jun 2013 09:16:31 +0800 From: Chen Gang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Thomas Gleixner CC: "linux-kernel@vger.kernel.org" Subject: [PATH v4] itimers: Remove bogus NULL pointer check in sys_getitimer() References: <51C2E6F9.80107@asianux.com> <51C3B4B4.90603@asianux.com> <51C8EB41.6060501@asianux.com> In-Reply-To: <51C8EB41.6060501@asianux.com> Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org People might be tricked into assuming that the return value for a failed NULL pointer check should be -EINVAL instead of -EFAULT. Remove the misleading NULL pointer check to fix this nuisance. Aside of that this patch fixes the problem of NOMMU kernels, where a NULL pointer dereference is a valid operation. This allows to boot NOMMU kernels without working around the shortcomings of the getitimer() system call, which have been ignored since this NULL pointer check was introduced in Linux 0.96a. Signed-off-by: Chen Gang --- kernel/itimer.c | 13 ++++++------- 1 files changed, 6 insertions(+), 7 deletions(-) diff --git a/kernel/itimer.c b/kernel/itimer.c index 8d262b4..3b12271 100644 --- a/kernel/itimer.c +++ b/kernel/itimer.c @@ -102,15 +102,14 @@ int do_getitimer(int which, struct itimerval *value) SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value) { - int error = -EFAULT; + int error; struct itimerval get_buffer; - if (value) { - error = do_getitimer(which, &get_buffer); - if (!error && - copy_to_user(value, &get_buffer, sizeof(get_buffer))) - error = -EFAULT; - } + error = do_getitimer(which, &get_buffer); + if (!error && + copy_to_user(value, &get_buffer, sizeof(get_buffer))) + error = -EFAULT; + return error; } -- 1.7.7.6