From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: possible circular locking dependency Date: Mon, 07 May 2012 10:52:44 +0300 Message-ID: <4FA77F4C.9080908@redhat.com> References: <20120503200259.GA3524@swordfish.minsk.epam.com> <4FA63C82.7030309@redhat.com> <20120506164209.GK2470@linux.vnet.ibm.com> <20120506203439.GB3633@swordfish> <20120507034744.GA3141@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Sergey Senozhatsky , Marcelo Tosatti , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Dave Jones To: paulmck@linux.vnet.ibm.com Return-path: In-Reply-To: <20120507034744.GA3141@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 05/07/2012 06:47 AM, Paul E. McKenney wrote: > On Sun, May 06, 2012 at 11:34:39PM +0300, Sergey Senozhatsky wrote: > > On (05/06/12 09:42), Paul E. McKenney wrote: > > > On Sun, May 06, 2012 at 11:55:30AM +0300, Avi Kivity wrote: > > > > On 05/03/2012 11:02 PM, Sergey Senozhatsky wrote: > > > > > Hello, > > > > > 3.4-rc5 > > > > > > > > Whoa. > > > > > > > > Looks like inconsistent locking between cpufreq and > > > > synchronize_srcu_expedited(). kvm triggered this because it is one of > > > > the few users of synchronize_srcu_expedited(), but I don't think it is > > > > doing anything wrong directly. > > > > > > > > Dave, Paul? > > > > > > SRCU hasn't changed much in mainline for quite some time. Holding > > > the hotplug mutex across a synchronize_srcu() is a bad idea, though. > > > > > > However, there is a reworked implementation (courtesy of Lai Jiangshan) > > > in -rcu that does not acquire the hotplug mutex. Could you try that out? > > > > > > > Paul, should I try solely -rcu or there are several commits to pick up and apply > > on top of -linus tree? > > If you want the smallest possible change, take the rcu/srcu branch of -rcu. > If you want the works, take the rcu/next branch of -rcu. > > You can find -rcu at: > > git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git To make the difference even smaller, merge the above branch with v3.4-rc5. -- error compiling committee.c: too many arguments to function