From: "Kirill A. Shutemov" Subject: Re: Deadlock on poweroff Date: Mon, 8 Oct 2012 08:30:29 +0300 Message-ID: <20121008053029.GA25145@shutemov.name> References: <20121007024711.GA21403@shutemov.name> <20121007160311.GE2485@linux.vnet.ibm.com> <20121007165012.GA23535@shutemov.name> <20121008044128.GA31861@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: "Paul E. McKenney" Return-path: Received: from shutemov.name ([176.9.204.213]:59918 "EHLO shutemov.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750799Ab2JHF3s (ORCPT ); Mon, 8 Oct 2012 01:29:48 -0400 Content-Disposition: inline In-Reply-To: <20121008044128.GA31861@linux.vnet.ibm.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: On Sun, Oct 07, 2012 at 09:41:28PM -0700, Paul E. McKenney wrote: > 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? Yep. Tested-by: Kirill A. Shutemov -- Kirill A. Shutemov