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Date: Fri, 13 Jul 2012 14:54:02 -0400
From: Dave Jones <davej@redhat.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Rusty Russell <rusty@rustcorp.com.au>, Darren Hart <darren@dvhart.com>,
        Peter Zijlstra <peterz@infradead.org>
Subject: Re: 3.5-rc6 futex_wait_requeue_pi oops.
Message-ID: <20120713185402.GA1707@redhat.com>
Mail-Followup-To: Dave Jones <davej@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Rusty Russell <rusty@rustcorp.com.au>,
	Darren Hart <darren@dvhart.com>,
	Peter Zijlstra <peterz@infradead.org>
References: <20120713180823.GA24972@redhat.com>
 <alpine.LFD.2.02.1207132032330.32033@ionos>
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On Fri, Jul 13, 2012 at 08:47:38PM +0200, Thomas Gleixner wrote:
 > On Fri, 13 Jul 2012, Dave Jones wrote:
 > 
 > > Looks like calling futex() with garbage makes things unhappy.
 > 
 >                 WARN_ON(!&q.pi_state);
 >                 pi_mutex = &q.pi_state->pi_mutex;
 >                 ret = rt_mutex_finish_proxy_lock(pi_mutex, to, &rt_waiter, 1);
 >                 debug_rt_mutex_free_waiter(&rt_waiter);
 > 
 > So there is some weird way which causes q.pi_state = NULL. Dave, did
 > you see the warning before the oops happened ?

No, that didn't seem to trigger.

	Dave