From: "Paul E. McKenney" Subject: Re: Deadlock on poweroff Date: Sun, 7 Oct 2012 21:41:28 -0700 Message-ID: <20121008044128.GA31861@linux.vnet.ibm.com> References: <20121007024711.GA21403@shutemov.name> <20121007160311.GE2485@linux.vnet.ibm.com> <20121007165012.GA23535@shutemov.name> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel@vger.kernel.org, Dipankar Sarma , Thomas Gleixner , Andrew Morton , Steffen Klassert , linux-crypto@vger.kernel.org To: "Kirill A. Shutemov" Return-path: Received: from e37.co.us.ibm.com ([32.97.110.158]:48896 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750857Ab2JHElh (ORCPT ); Mon, 8 Oct 2012 00:41:37 -0400 Received: from /spool/local by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sun, 7 Oct 2012 22:41:36 -0600 Content-Disposition: inline In-Reply-To: <20121007165012.GA23535@shutemov.name> Sender: linux-crypto-owner@vger.kernel.org List-ID: On Sun, Oct 07, 2012 at 07:50:12PM +0300, Kirill A. Shutemov wrote: > On Sun, Oct 07, 2012 at 09:03:11AM -0700, Paul E. McKenney wrote: > > On Sun, Oct 07, 2012 at 05:47:11AM +0300, Kirill A. Shutemov wrote: > > > Hi Paul and all, > > > > > > With commit 755609a9087fa983f567dc5452b2fa7b089b591f I've got deadlock on > > > poweroff. > > > > > > It guess it happens because of race for cpu_hotplug.lock: > > > > > > CPU A CPU B > > > disable_nonboot_cpus() > > > _cpu_down() > > > cpu_hotplug_begin() > > > mutex_lock(&cpu_hotplug.lock); > > > __cpu_notify() > > > padata_cpu_callback() > > > __padata_remove_cpu() > > > padata_replace() > > > synchronize_rcu() > > > rcu_gp_kthread() > > > get_online_cpus(); > > > mutex_lock(&cpu_hotplug.lock); > > > > > > Have you seen the issue before? > > > > This is a new one for me. Does the following (very lightly tested) > > patch help? > > Works for me. Thanks. May I add your Tested-by? Thanx, Paul