From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933169Ab2BBSEn (ORCPT ); Thu, 2 Feb 2012 13:04:43 -0500 Received: from e9.ny.us.ibm.com ([32.97.182.139]:37387 "EHLO e9.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932854Ab2BBSEl (ORCPT ); Thu, 2 Feb 2012 13:04:41 -0500 Date: Thu, 2 Feb 2012 10:03:09 -0800 From: "Paul E. McKenney" To: Julia Lawall Cc: Josh Triplett , linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, fweisbec@gmail.com, patches@linaro.org, "Paul E. McKenney" , Julia Lawall Subject: Re: [PATCH RFC tip/core/rcu 31/41] rcu: Add CPU-stall capability to rcutorture Message-ID: <20120202180309.GY2518@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20120201194131.GA10028@linux.vnet.ibm.com> <1328125319-5205-1-git-send-email-paulmck@linux.vnet.ibm.com> <1328125319-5205-31-git-send-email-paulmck@linux.vnet.ibm.com> <20120202055310.GR29058@leaf> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12020218-7182-0000-0000-000000A780DB Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 02, 2012 at 10:15:45AM +0100, Julia Lawall wrote: > > > On Wed, 1 Feb 2012, Josh Triplett wrote: > > >On Wed, Feb 01, 2012 at 11:41:49AM -0800, Paul E. McKenney wrote: > >>--- a/kernel/rcutorture.c > >>+++ b/kernel/rcutorture.c > >>+/* Spawn CPU-stall kthread, if stall_cpu specified. */ > >>+static int __init rcu_torture_stall_init(void) > >>+{ > >>+ if (stall_cpu <= 0) > >>+ return 0; > >>+ stall_task = kthread_run(rcu_torture_stall, NULL, "rcu_torture_stall"); > >>+ if (IS_ERR(stall_task)) { > >>+ stall_task = NULL; > >>+ return PTR_ERR(stall_task); > > > >This seems...unlikely to produce the desired result. :) > > > >A quick check turns up the same bug in rcutorture_onoff_init. > > > >This suggests a possible Coccinelle check, for uses of PTR_ERR(foo) after > >foo = (any constant other than ERR_PTR(foo)). > > Indeed, it seems to be a popular idiom :) I'll send some patches > later today. I guess I am glad that I am not the only idiot out there... Thanx, Paul