Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756214Ab3DAAIb (ORCPT ); Sun, 31 Mar 2013 20:08:31 -0400 Received: from intranet.asianux.com ([58.214.24.6]:14323 "EHLO intranet.asianux.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756041Ab3DAAIa (ORCPT ); Sun, 31 Mar 2013 20:08:30 -0400 X-Spam-Score: -100.7 Message-ID: <5158CFDF.4060700@asianux.com> Date: Mon, 01 Apr 2013 08:07:59 +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: Frederic Weisbecker CC: Andrew Morton , LKML , Stanislaw Gruszka , Thomas Gleixner , Peter Zijlstra , Ingo Molnar , Oleg Nesterov Subject: Re: [PATCH 1/3] posix-timers: Correctly get dying task time sample in posix_cpu_timer_schedule() References: <1364649331-30940-1-git-send-email-fweisbec@gmail.com> <1364649331-30940-2-git-send-email-fweisbec@gmail.com> In-Reply-To: <1364649331-30940-2-git-send-email-fweisbec@gmail.com> Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1523 Lines: 44 On 2013??03??30?? 21:15, Frederic Weisbecker wrote: > In order to arm the next timer to schedule, we take a sample of the > current process or thread cputime. > > If the task is dying though, we don't arm anything but we > cache the remaining timer expiration delta for further reads. > > Something similar is performed in posix_cpu_timer_get() but > here we forget to take the process wide cputime sample > before caching it. > > As a result we are storing random stack content, leading > every further reads of that timer to return junk values. > > Fix this by taking the appropriate sample in the case of > process wide timers. > > Reported-by: Andrew Morton > Reported-by: Chen Gang > Signed-off-by: Frederic Weisbecker > Cc: Stanislaw Gruszka > Cc: Thomas Gleixner > Cc: Peter Zijlstra > Cc: Ingo Molnar > Cc: Oleg Nesterov > Cc: Chen Gang > --- thank you for mark me as reported by, although I reported too late (Andrew Morton is the first reporter). next, I should continue to try to find another issues about kernel. :-) -- Chen Gang Asianux Corporation -- 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/