Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755911Ab0KPRb0 (ORCPT ); Tue, 16 Nov 2010 12:31:26 -0500 Received: from mga14.intel.com ([143.182.124.37]:23220 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753372Ab0KPRbZ (ORCPT ); Tue, 16 Nov 2010 12:31:25 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.59,206,1288594800"; d="scan'208";a="349490968" Message-ID: <4CE2BFBF.3010900@linux.intel.com> Date: Tue, 16 Nov 2010 09:30:39 -0800 From: Darren Hart User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.12) Gecko/20101027 Lightning/1.0b2 Thunderbird/3.1.6 MIME-Version: 1.0 To: "Aguirre, Sergio" CC: LKML , Thomas Gleixner , Peter Zijlstra , Ingo Molnar , Namhyung Kim Subject: Re: [RFC][PATCH] futex: Hide false positive about uninit var usage References: <1289925157-17054-1-git-send-email-saaguirre@ti.com> <4CE2B4AC.5080606@linux.intel.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2716 Lines: 91 On 11/16/2010 08:59 AM, Aguirre, Sergio wrote: > Hi Darren, > >> -----Original Message----- >> From: Darren Hart [mailto:dvhart@linux.intel.com] >> Sent: Tuesday, November 16, 2010 10:43 AM >> To: Aguirre, Sergio >> Cc: LKML; Thomas Gleixner; Peter Zijlstra; Ingo Molnar; Namhyung Kim >> Subject: Re: [RFC][PATCH] futex: Hide false positive about uninit var >> usage >> >> On 11/16/2010 08:32 AM, Sergio Aguirre wrote: >>> In exit_robust_list, there was this warning shown: >>> >>> kernel/futex.c: In function 'exit_robust_list': >>> kernel/futex.c:2492: warning: 'next_pi' may be used uninitialized in >> this function >>> >>> Which is a false positive, since in the function, the only scenario >>> possible in which the var is read, is after a successful excecution of >>> fetch_robust_entry, which populates the variable. >>> >>> So there's no real possibility of it being used uninitialized. >> >> Hi Sergio, >> >> You are correct. Thomas has recently pulled my fix for this into tip, it >> should be queued for mainline already. > > Oh ok. Sorry, I didn't know that. Please ignore this patch then. No problem. In the future, if you run into problems with futexes, check the linux-2.6-tip repository for fixes as that is where they are queued up before going into mainline. git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git branch: core/futexes Thanks, Darren > > Regards, > Sergio > >> >> Thanks, >> >> Darren Hart >> >>> >>> Signed-off-by: Sergio Aguirre >>> Cc: Thomas Gleixner >>> Cc: Peter Zijlstra >>> Cc: Darren Hart >>> Cc: Ingo Molnar >>> Cc: Namhyung Kim >>> --- >>> kernel/futex.c | 3 ++- >>> 1 files changed, 2 insertions(+), 1 deletions(-) >>> >>> diff --git a/kernel/futex.c b/kernel/futex.c >>> index 6c683b3..3646157 100644 >>> --- a/kernel/futex.c >>> +++ b/kernel/futex.c >>> @@ -2489,7 +2489,8 @@ void exit_robust_list(struct task_struct *curr) >>> { >>> struct robust_list_head __user *head = curr->robust_list; >>> struct robust_list __user *entry, *next_entry, *pending; >>> - unsigned int limit = ROBUST_LIST_LIMIT, pi, next_pi, pip; >>> + unsigned int limit = ROBUST_LIST_LIMIT, pi; >>> + unsigned int uninitialized_var(next_pi), pip; >>> unsigned long futex_offset; >>> int rc; >>> >> >> >> -- >> Darren Hart >> Yocto Linux Kernel -- Darren Hart Yocto Linux Kernel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/