Message-ID: <4FA77F4C.9080908@redhat.com>
Date: Mon, 07 May 2012 10:52:44 +0300
From: Avi Kivity <avi@redhat.com>
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To: paulmck@linux.vnet.ibm.com
CC: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Marcelo Tosatti <mtosatti@redhat.com>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, Dave Jones <davej@redhat.com>
Subject: Re: possible circular locking dependency
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>
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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

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