From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933137Ab1LFJxb (ORCPT ); Tue, 6 Dec 2011 04:53:31 -0500 Received: from merlin.infradead.org ([205.233.59.134]:55687 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933063Ab1LFJxa convert rfc822-to-8bit (ORCPT ); Tue, 6 Dec 2011 04:53:30 -0500 Message-ID: <1323165152.32012.51.camel@twins> Subject: Re: [PATCH RFC tip/core/rcu 7/7] rcu: Quiet RCU-lockdep warnings involving interrupt disabling From: Peter Zijlstra To: Yong Zhang Cc: "Paul E. McKenney" , linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, patches@linaro.org Date: Tue, 06 Dec 2011 10:52:32 +0100 In-Reply-To: <20111206012635.GA32498@zhy> References: <20111203183417.GA18914@linux.vnet.ibm.com> <1322937282-19846-7-git-send-email-paulmck@linux.vnet.ibm.com> <20111205091924.GA28117@zhy> <20111205164505.GB2326@linux.vnet.ibm.com> <20111206012635.GA32498@zhy> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Mailer: Evolution 3.2.1- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2011-12-06 at 09:26 +0800, Yong Zhang wrote: > Yeah, because we call might_sleep() in rt_mutex_lock() unconditionally. > But in this case the 'BUG: sleeping function called from invalid context > at *' is obviously false positive. Why can't this mutex acquisition not block? > Maybe we could teach might_sleep() about this special case? Sounds horrid.