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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: linux-kernel@vger.kernel.org,
	Dipankar Sarma <dipankar@in.ibm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Steffen Klassert <steffen.klassert@secunet.com>,
	linux-crypto@vger.kernel.org
Subject: Re: Deadlock on poweroff
Date: Sun, 7 Oct 2012 21:41:28 -0700	[thread overview]
Message-ID: <20121008044128.GA31861@linux.vnet.ibm.com> (raw)
In-Reply-To: <20121007165012.GA23535@shutemov.name>

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


  parent reply	other threads:[~2012-10-08  4:41 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-07  2:47 Deadlock on poweroff Kirill A. Shutemov
     [not found] ` <20121007160311.GE2485@linux.vnet.ibm.com>
2012-10-07 16:50   ` Kirill A. Shutemov
2012-10-07 17:05     ` Srivatsa S. Bhat
2012-10-07 17:11       ` Kirill A. Shutemov
2012-10-07 17:16         ` Srivatsa S. Bhat
2012-10-07 21:08           ` Paul E. McKenney
2012-10-08  4:41     ` Paul E. McKenney [this message]
2012-10-08  5:30       ` Kirill A. Shutemov

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