From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752848Ab2BBFxg (ORCPT ); Thu, 2 Feb 2012 00:53:36 -0500 Received: from relay4-d.mail.gandi.net ([217.70.183.196]:46259 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751249Ab2BBFxf (ORCPT ); Thu, 2 Feb 2012 00:53:35 -0500 X-Originating-IP: 217.70.178.132 X-Originating-IP: 50.43.15.19 Date: Wed, 1 Feb 2012 21:53:11 -0800 From: Josh Triplett To: "Paul E. McKenney" Cc: 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: <20120202055310.GR29058@leaf> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1328125319-5205-31-git-send-email-paulmck@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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)). - Josh Triplett