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Date: Fri, 20 Jul 2012 09:35:01 -0400
From: Dave Jones <davej@redhat.com>
To: Darren Hart <dvhart@linux.intel.com>
Cc: 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>
Subject: Re: 3.5-rc6 futex_wait_requeue_pi oops.
Message-ID: <20120720133501.GA30826@redhat.com>
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	Rusty Russell <rusty@rustcorp.com.au>,
	Darren Hart <darren@dvhart.com>,
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On Thu, Jul 19, 2012 at 11:53:45PM -0700, Darren Hart wrote:

 
 > >> I'll add a fix to that WARN_ON in my futex-fixes branch along with the
 > >> fix for the bug Dan found.
 > > 
 > > I think I have root cause. futex_wait_requeue_pi() doesn't like having
 > > uaddr == uaddr2. The handle_early_wakeup() doesn't detect a problem
 > > because key2 IS the same as key1, I think. I've just discovered this and
 > > quickly hacked in a "if (uaddr==uaddr2) return -EINVAL" fix and the test
 > > continues to run (with just ops 0, 11, 12) for several minutes now
 > > (typically fails in a few seconds). I'll let it run for a few hours and
 > > contemplate the proper fix.
 > 
 > Dave, mind giving this a spin? It seems to be doing the trick here,
 > at least for the *REQUEUE_PI futex op codes in trinity.

Yeah, looks like that does the trick!

thanks,

	Dave