From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261564AbVCTGh1 (ORCPT ); Sun, 20 Mar 2005 01:37:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262019AbVCTGh1 (ORCPT ); Sun, 20 Mar 2005 01:37:27 -0500 Received: from dbl.q-ag.de ([213.172.117.3]:733 "EHLO dbl.q-ag.de") by vger.kernel.org with ESMTP id S261564AbVCTGhW (ORCPT ); Sun, 20 Mar 2005 01:37:22 -0500 Message-ID: <423D19FE.7020902@colorfullife.com> Date: Sun, 20 Mar 2005 07:36:46 +0100 From: Manfred Spraul User-Agent: Mozilla/5.0 (X11; U; Linux i686; fr-FR; rv:1.7.3) Gecko/20041020 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Ingo Molnar CC: "Paul E. McKenney" , dipankar@in.ibm.com, shemminger@osdl.org, akpm@osdl.org, torvalds@osdl.org, rusty@au1.ibm.com, tgall@us.ibm.com, jim.houston@comcast.net, gh@us.ibm.com, linux-kernel@vger.kernel.org Subject: Re: Real-Time Preemption and RCU References: <20050318002026.GA2693@us.ibm.com> <20050318091303.GB9188@elte.hu> <20050318092816.GA12032@elte.hu> <423BB299.4010906@colorfullife.com> <20050319162601.GA28958@elte.hu> In-Reply-To: <20050319162601.GA28958@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: >which precise locking situation do you mean? > > > cpu 1: acquire random networking spin_lock_bh() cpu 2: read_lock(&tasklist_lock) from process context interrupt. softirq. within softirq: try to acquire the networking lock. * spins. cpu 1: hardware interrupt within hw interrupt: signal delivery. tries to acquire tasklist_lock. --> deadlock. -- Manfred