From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753228Ab2D3HBd (ORCPT ); Mon, 30 Apr 2012 03:01:33 -0400 Received: from e28smtp03.in.ibm.com ([122.248.162.3]:45347 "EHLO e28smtp03.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751433Ab2D3HBb (ORCPT ); Mon, 30 Apr 2012 03:01:31 -0400 Message-ID: <4F9E38A7.9030209@linux.vnet.ibm.com> Date: Mon, 30 Apr 2012 12:30:55 +0530 From: "Srivatsa S. Bhat" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120329 Thunderbird/11.0.1 MIME-Version: 1.0 To: lenb@kernel.org, "Rafael J. Wysocki" , "akpm@linux-foundation.org" CC: Daniel Lezcano , khilman@ti.com, Deepthi Dharwar , g.trinabh@gmail.com, Arjan van de Ven , "linux-kernel@vger.kernel.org" , Linux PM mailing list , "Srivatsa S. Bhat" Subject: [PATCH v2][RESEND] cpuidle: Add checks to avoid NULL pointer dereference Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit x-cbid: 12043007-3864-0000-0000-0000027CAFD2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Srivatsa S. Bhat The existing check for dev == NULL in __cpuidle_register_device() is rendered useless because dev is dereferenced before the check itself. Moreover, correctly speaking, it is the job of the callers of this function, i.e., cpuidle_register_device() & cpuidle_enable_device() (which also happen to be exported functions) to ensure that __cpuidle_register_device() is called with a non-NULL dev. So add the necessary dev == NULL checks in the two callers and remove the (useless) check from __cpuidle_register_device(). Signed-off-by: Srivatsa S. Bhat Acked-by: Daniel Lezcano --- drivers/cpuidle/cpuidle.c | 8 ++++++-- 1 files changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 87411ce..eae2f11 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -291,6 +291,9 @@ int cpuidle_enable_device(struct cpuidle_device *dev) int ret, i; struct cpuidle_driver *drv = cpuidle_get_driver(); + if (!dev) + return -EINVAL; + if (dev->enabled) return 0; if (!drv || !cpuidle_curr_governor) @@ -375,8 +378,6 @@ static int __cpuidle_register_device(struct cpuidle_device *dev) struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); - if (!dev) - return -EINVAL; if (!try_module_get(cpuidle_driver->owner)) return -EINVAL; @@ -401,6 +402,9 @@ int cpuidle_register_device(struct cpuidle_device *dev) { int ret; + if (!dev) + return -EINVAL; + mutex_lock(&cpuidle_lock); if ((ret = __cpuidle_register_device(dev))) {