From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756242Ab2CWLcr (ORCPT ); Fri, 23 Mar 2012 07:32:47 -0400 Received: from mga03.intel.com ([143.182.124.21]:41872 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755685Ab2CWLcq convert rfc822-to-8bit (ORCPT ); Fri, 23 Mar 2012 07:32:46 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="80810715" From: "Liu, Chuansheng" To: Peter Zijlstra CC: "linux-kernel@vger.kernel.org" , Yanmin Zhang , "tglx@linutronix.de" , "Srivatsa S. Bhat" Subject: RE: [PATCH] Fix the race between smp_call_function and CPU booting Thread-Topic: [PATCH] Fix the race between smp_call_function and CPU booting Thread-Index: AQHNCN9MKF1rJY3aXUun4qztc3puMZZ3vcqg Date: Fri, 23 Mar 2012 11:32:43 +0000 Message-ID: <27240C0AC20F114CBF8149A2696CBE4A05D65B@SHSMSX101.ccr.corp.intel.com> References: <27240C0AC20F114CBF8149A2696CBE4A053BE8@SHSMSX101.ccr.corp.intel.com> <1331546307.18960.26.camel@twins> <27240C0AC20F114CBF8149A2696CBE4A054D70@SHSMSX101.ccr.corp.intel.com> <1331654251.18960.78.camel@twins> <27240C0AC20F114CBF8149A2696CBE4A0556FA@SHSMSX101.ccr.corp.intel.com> <1331718197.18960.106.camel@twins> <27240C0AC20F114CBF8149A2696CBE4A056F47@SHSMSX101.ccr.corp.intel.com> <1331808391.18960.160.camel@twins> <27240C0AC20F114CBF8149A2696CBE4A05806B@SHSMSX101.ccr.corp.intel.com> <1331891364.18960.221.camel@twins> <27240C0AC20F114CBF8149A2696CBE4A058AAE@SHSMSX101.ccr.corp.intel.com> <1332151397.18960.252.camel@twins> <27240C0AC20F114CBF8149A2696CBE4A05A6BF@SHSMSX101.ccr.corp.intel.com> <1332245842.18960.413.camel@twins> <27240C0AC20F114CBF8149A2696CBE4A05B485@SHSMSX101.ccr.corp.intel.com> <1332332739.18960.488.camel@twins> <27240C0AC20F114CBF8149A2696CBE4A05C092@SHSMSX101.ccr.corp.intel.com> <1332498333.16159.9.camel@twins> In-Reply-To: <1332498333.16159.9.camel@twins> Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In fact, I started two scripts running: 1/ One script: echo 0 > /sys/devices/system/cpuX/online echo 1 > /sys/devices/system/cpuX/online Rerunning the above commands in loop 2/Another script: echo 1 > /debug/smp_call_test usleep 50000 Rerunning the above command in loop This race issue can be easy to be reproduced in several minutes; For simplify your test as mine(just two CPUs), you can set other non-booting CPUs as offline at first and just leave one non-booting CPU. > -----Original Message----- > From: Peter Zijlstra [mailto:peterz@infradead.org] > Sent: Friday, March 23, 2012 6:26 PM > To: Liu, Chuansheng > Cc: linux-kernel@vger.kernel.org; Yanmin Zhang; tglx@linutronix.de; Srivatsa S. > Bhat > Subject: RE: [PATCH] Fix the race between smp_call_function and CPU booting > > On Thu, 2012-03-22 at 00:59 +0000, Liu, Chuansheng wrote: > > Below is the complete test patch. Just run the simpl_loop_onoffline.sh > > and simpl_loop_smpcalling.sh concurrently to reproduce the race. > > > What I did was: > > for i in {2..23} ; do echo 0 > /sys/devices/system/cpu/cpu${i}/online ; done while > usleep 50000 ; do echo 1 > /debug/smp_call_test ; done & while :; do echo $i > > /sys/devices/system/cpu/cpu1/online ; let i^=1 ; done > > and this has been running for well over 30 minutes.. is there anything else one > needs to do? >