From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Avi Kivity <avi@redhat.com>
Cc: paulmck@linux.vnet.ibm.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
Date: Tue, 8 May 2012 01:10:04 +0300 [thread overview]
Message-ID: <20120507221004.GD4469@swordfish> (raw)
In-Reply-To: <4FA77F4C.9080908@redhat.com>
On (05/07/12 10:52), Avi Kivity wrote:
> 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.
>
I'm unable to reproduce the issue on 3.4-rc6 so far. So I guess this will
take some time.
Sergey
next prev parent reply other threads:[~2012-05-07 22:10 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-03 20:02 possible circular locking dependency Sergey Senozhatsky
2012-05-06 8:55 ` Avi Kivity
2012-05-06 16:42 ` Paul E. McKenney
2012-05-06 20:34 ` Sergey Senozhatsky
2012-05-07 3:47 ` Paul E. McKenney
2012-05-07 7:52 ` Avi Kivity
2012-05-07 22:10 ` Sergey Senozhatsky [this message]
-- strict thread matches above, loose matches on Subject: below --
2009-09-21 14:00 Christof Schmitt
2009-11-10 13:33 ` Christof Schmitt
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